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Rohloff + Schlumpf
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Alan Braggins
Mar 14, 2019, 3:39:34 PM3/14/19
to
The idea of combining a Rohloff and Schlumpf has come up before in this
group, but I don't think I've seen it actually being done. Nor did I realise
previously that you could combine a Schlumpf with a tandem timing chain,
though the Schlumpf FAQ does mention it as possible.
https://www.ebay.co.uk/itm/rohloff-equipped-schlumpf-high-and-low-thorn-raven-twin-tour-tandem-bike-/123677804461
(http://www.schlumpf.ch/hp/schlumpf/faq.getriebe.engl.htm#C does warn
"For a combination with a Rohloff hub (not recommended by Rohloff, as
torque coming from the mountain-drive can exceed limitation of entry
torque of the Rohloff hub) ...."
It's not clear to me from the eBay listing which version of Schlumpf it is.)
group, but I don't think I've seen it actually being done. Nor did I realise
previously that you could combine a Schlumpf with a tandem timing chain,
though the Schlumpf FAQ does mention it as possible.
https://www.ebay.co.uk/itm/rohloff-equipped-schlumpf-high-and-low-thorn-raven-twin-tour-tandem-bike-/123677804461
(http://www.schlumpf.ch/hp/schlumpf/faq.getriebe.engl.htm#C does warn
"For a combination with a Rohloff hub (not recommended by Rohloff, as
torque coming from the mountain-drive can exceed limitation of entry
torque of the Rohloff hub) ...."
It's not clear to me from the eBay listing which version of Schlumpf it is.)
Nick Maclaren
Mar 14, 2019, 6:26:37 PM3/14/19
to
In article <slrnq8l17...@chiark.greenend.org.uk>,
If you visited me, I could show you.
>(http://www.schlumpf.ch/hp/schlumpf/faq.getriebe.engl.htm#C does warn
>"For a combination with a Rohloff hub (not recommended by Rohloff, as
> torque coming from the mountain-drive can exceed limitation of entry
> torque of the Rohloff hub) ...."
It can. However, to exceed the 100 nm at the hub, I would have to
push 65 Kg on the pedal - which, even at a cadence of 40 RPM, would
be 260 watts. NO chance! The essential thing to avoid is catching
the trike with the pedals in low range when it rolls backwards downhill.
Essentially, I use the 20"-100" range with the mountain drive in
direct drive almost all of the time, and stop and select low range
only when I get stuck. I am not good at changing the Schlumpf on the
move, but so what? A bottom gear of 8" enables me to get up 15% with
a full touring load.
Regards,
Nick Maclaren.
Alan Braggins <ar...@chiark.greenend.org.uk> wrote:
>The idea of combining a Rohloff and Schlumpf has come up before in this
>group, but I don't think I've seen it actually being done. ...
>The idea of combining a Rohloff and Schlumpf has come up before in this
If you visited me, I could show you.
>(http://www.schlumpf.ch/hp/schlumpf/faq.getriebe.engl.htm#C does warn
>"For a combination with a Rohloff hub (not recommended by Rohloff, as
> torque coming from the mountain-drive can exceed limitation of entry
> torque of the Rohloff hub) ...."
push 65 Kg on the pedal - which, even at a cadence of 40 RPM, would
be 260 watts. NO chance! The essential thing to avoid is catching
the trike with the pedals in low range when it rolls backwards downhill.
Essentially, I use the 20"-100" range with the mountain drive in
direct drive almost all of the time, and stop and select low range
only when I get stuck. I am not good at changing the Schlumpf on the
move, but so what? A bottom gear of 8" enables me to get up 15% with
a full touring load.
Regards,
Nick Maclaren.
Tosspot
Mar 15, 2019, 1:18:39 PM3/15/19
to
Drive (Direct in high gear) and worked fine. The one issue is that you
need to machine the BB (tool available) to fit one. The gear change
isn't quite as convenient as Schlumpf would like, but usually you flick
the drive and stay there for a good while.
Zebee Johnstone
Mar 15, 2019, 4:02:23 PM3/15/19
to
In uk.rec.cycling.moderated on Fri, 15 Mar 2019 18:18:28 +0100
I found the MOuntain Drive unpleasantly mushy on my 2 wheel 'bent with
a Shimano Alfine hub gear. Just felt nasty.
Direct drive was fine but the low range felt energy-sapping. OK if I
spun a bit more, so closer to 80 than 60, but that was surprisingly
hard work on the sort of hills you need it on!
It also made hill starts just that much harder.
I think it would be better on a trike or a diamond frame without the
particular balance problems of a high racer 'bent. If I was able to
go touring again I'd ponder a mountain drive for the trike.
Zebee
a Shimano Alfine hub gear. Just felt nasty.
Direct drive was fine but the low range felt energy-sapping. OK if I
spun a bit more, so closer to 80 than 60, but that was surprisingly
hard work on the sort of hills you need it on!
It also made hill starts just that much harder.
I think it would be better on a trike or a diamond frame without the
particular balance problems of a high racer 'bent. If I was able to
go touring again I'd ponder a mountain drive for the trike.
Zebee
Nick Maclaren
Mar 16, 2019, 6:26:31 AM3/16/19
to
In article <slrnq8o15p...@gmail.com>,
change cadence and don't find it energy sapping or difficult on hill
starts. Of course, that's on a trike, but I don't believe that ANY
gear of 8" (which is what I have) would be good for hill starts on
any bicycle ridden by anyone!
Regards,
Nick Maclaren.
Zebee Johnstone <zeb...@gmail.com> wrote:
>
>I found the MOuntain Drive unpleasantly mushy on my 2 wheel 'bent with
>a Shimano Alfine hub gear. Just felt nasty.
>
>Direct drive was fine but the low range felt energy-sapping. OK if I
>spun a bit more, so closer to 80 than 60, but that was surprisingly
>hard work on the sort of hills you need it on!
>
>It also made hill starts just that much harder.
I find it spongey, too, and it probably wastes energy, but I don't
>
>I found the MOuntain Drive unpleasantly mushy on my 2 wheel 'bent with
>a Shimano Alfine hub gear. Just felt nasty.
>
>Direct drive was fine but the low range felt energy-sapping. OK if I
>spun a bit more, so closer to 80 than 60, but that was surprisingly
>hard work on the sort of hills you need it on!
>
>It also made hill starts just that much harder.
change cadence and don't find it energy sapping or difficult on hill
starts. Of course, that's on a trike, but I don't believe that ANY
gear of 8" (which is what I have) would be good for hill starts on
any bicycle ridden by anyone!
Regards,
Nick Maclaren.
David Damerell
Mar 16, 2019, 4:32:37 PM3/16/19
to
Quoting Alan Braggins <ar...@chiark.greenend.org.uk>:
>The idea of combining a Rohloff and Schlumpf has come up before in this
>group, but I don't think I've seen it actually being done. Nor did I realise
>previously that you could combine a Schlumpf with a tandem timing chain,
>though the Schlumpf FAQ does mention it as possible.
It does seem a bit like overkill. I mean, I know as well as anyone you
>The idea of combining a Rohloff and Schlumpf has come up before in this
>group, but I don't think I've seen it actually being done. Nor did I realise
>previously that you could combine a Schlumpf with a tandem timing chain,
>though the Schlumpf FAQ does mention it as possible.
want a very wide gear range on a tandem, but the tandem-and-Rohloff owners
I know seem to find it satisfactory.
Also, it restores a disadvantage of conventional drivetrains on a tandem;
when the captain says there is going to be a gear change (perhaps at the
stoker's request), it's not clear if it's going to be a small one or a
large one perhaps followed by some small ones in the opposite direction.
--
David Damerell <dame...@chiark.greenend.org.uk>
If we aren't perfectly synchronised this corncob will explode!
Today is First Gloucesterday, March.
Tomorrow will be First Leicesterday, March.
Zebee Johnstone
Mar 16, 2019, 4:46:50 PM3/16/19
to
In uk.rec.cycling.moderated on 14 Mar 2019 20:55:51 +0000 (GMT)
I know there are some aftermarket shifters, I have pondered a Rholoff
but I hate twistgrips on J bars or superman bars. Nasty wrist motion.
Greenspeed have a workaround so you can use a twistgrip on their bars
but it means hand movement to change gears.
I use a trigger shifter on the Encore to work the Alfine hub gear. I
only just have leg clearance and even then I have been known to snag
floppier shorts on them. Having hub gear is worth it...
Zebee
David Damerell <dame...@chiark.greenend.org.uk> wrote:
> Quoting Alan Braggins <ar...@chiark.greenend.org.uk>:
>>The idea of combining a Rohloff and Schlumpf has come up before in this
>>group, but I don't think I've seen it actually being done. Nor did I realise
>>previously that you could combine a Schlumpf with a tandem timing chain,
>>though the Schlumpf FAQ does mention it as possible.
>
> It does seem a bit like overkill. I mean, I know as well as anyone you
> want a very wide gear range on a tandem, but the tandem-and-Rohloff owners
> I know seem to find it satisfactory.
Anyone come across a non-twistgrip Rohloff?
> Quoting Alan Braggins <ar...@chiark.greenend.org.uk>:
>>The idea of combining a Rohloff and Schlumpf has come up before in this
>>group, but I don't think I've seen it actually being done. Nor did I realise
>>previously that you could combine a Schlumpf with a tandem timing chain,
>>though the Schlumpf FAQ does mention it as possible.
>
> It does seem a bit like overkill. I mean, I know as well as anyone you
> want a very wide gear range on a tandem, but the tandem-and-Rohloff owners
> I know seem to find it satisfactory.
I know there are some aftermarket shifters, I have pondered a Rholoff
but I hate twistgrips on J bars or superman bars. Nasty wrist motion.
Greenspeed have a workaround so you can use a twistgrip on their bars
but it means hand movement to change gears.
I use a trigger shifter on the Encore to work the Alfine hub gear. I
only just have leg clearance and even then I have been known to snag
floppier shorts on them. Having hub gear is worth it...
Zebee
Tosspot
Mar 17, 2019, 6:48:33 AM3/17/19
to
On 3/16/19 9:46 PM, Zebee Johnstone wrote:
> In uk.rec.cycling.moderated on 14 Mar 2019 20:55:51 +0000 (GMT)
> David Damerell <dame...@chiark.greenend.org.uk> wrote:
>> Quoting Alan Braggins <ar...@chiark.greenend.org.uk>:
>>> The idea of combining a Rohloff and Schlumpf has come up before in this
>>> group, but I don't think I've seen it actually being done. Nor did I realise
>>> previously that you could combine a Schlumpf with a tandem timing chain,
>>> though the Schlumpf FAQ does mention it as possible.
>>
>> It does seem a bit like overkill. I mean, I know as well as anyone you
>> want a very wide gear range on a tandem, but the tandem-and-Rohloff owners
>> I know seem to find it satisfactory.
>
> Anyone come across a non-twistgrip Rohloff?
Rocking horse shit. If anyone finds one please let me know!
> In uk.rec.cycling.moderated on 14 Mar 2019 20:55:51 +0000 (GMT)
> David Damerell <dame...@chiark.greenend.org.uk> wrote:
>> Quoting Alan Braggins <ar...@chiark.greenend.org.uk>:
>>> The idea of combining a Rohloff and Schlumpf has come up before in this
>>> group, but I don't think I've seen it actually being done. Nor did I realise
>>> previously that you could combine a Schlumpf with a tandem timing chain,
>>> though the Schlumpf FAQ does mention it as possible.
>>
>> It does seem a bit like overkill. I mean, I know as well as anyone you
>> want a very wide gear range on a tandem, but the tandem-and-Rohloff owners
>> I know seem to find it satisfactory.
>
> Anyone come across a non-twistgrip Rohloff?
> I know there are some aftermarket shifters, I have pondered a Rholoff
> but I hate twistgrips on J bars or superman bars. Nasty wrist motion.
> Greenspeed have a workaround so you can use a twistgrip on their bars
> but it means hand movement to change gears.
>
> I use a trigger shifter on the Encore to work the Alfine hub gear. I
> only just have leg clearance and even then I have been known to snag
> floppier shorts on them. Having hub gear is worth it...
https://www.rohloff.de/en/products/speedhub/e-14/
I didn't check the price...
Zebee Johnstone
Mar 17, 2019, 4:55:29 PM3/17/19
to
In uk.rec.cycling.moderated on Sun, 17 Mar 2019 11:48:12 +0100
An individual price is not available as the E-14 shifting system is
currently, at the time of press (September 2017), only available to OEM
bicycle manufacturers for sale in complete, new bicycles.
Can the Rohloff E-14 electronic shifting system be used on a bicycle
without electric mid-motor support?
No, the Rohloff E-14 shifting system is currently only compatible
with bicycles using the Bosch eBike system. At this point in time,
unfortunately not feasible as the current E-14 units require the power
source and cock-pit of a Bosch eBike system running the compatible
software. We are aware of the demand for a non-Ebike dependent Rohloff
E-14 version however the implementation of this will require further
development and thus time. We will inform you through our website and
social media pages as soon as there is more information on these projects.
Zebee
Tosspot <Frank...@gmail.com> wrote:
>
> Best option so far imho
>
> https://www.rohloff.de/en/products/speedhub/e-14/
>
> I didn't check the price...
Alas it's non-compatible rocking horse shit...
>
> Best option so far imho
>
> https://www.rohloff.de/en/products/speedhub/e-14/
>
> I didn't check the price...
An individual price is not available as the E-14 shifting system is
currently, at the time of press (September 2017), only available to OEM
bicycle manufacturers for sale in complete, new bicycles.
Can the Rohloff E-14 electronic shifting system be used on a bicycle
without electric mid-motor support?
No, the Rohloff E-14 shifting system is currently only compatible
with bicycles using the Bosch eBike system. At this point in time,
unfortunately not feasible as the current E-14 units require the power
source and cock-pit of a Bosch eBike system running the compatible
software. We are aware of the demand for a non-Ebike dependent Rohloff
E-14 version however the implementation of this will require further
development and thus time. We will inform you through our website and
social media pages as soon as there is more information on these projects.
Zebee
Kim Wall
Mar 17, 2019, 7:30:25 PM3/17/19
to
On 14/03/2019 20:55, David Damerell wrote:
> Also, it restores a disadvantage of conventional drivetrains on a tandem;
> when the captain says there is going to be a gear change (perhaps at the
> stoker's request), it's not clear if it's going to be a small one or a
> large one perhaps followed by some small ones in the opposite direction.
Surely on a tandem the stoker would be in charge of shifting the
> Also, it restores a disadvantage of conventional drivetrains on a tandem;
> when the captain says there is going to be a gear change (perhaps at the
> stoker's request), it's not clear if it's going to be a small one or a
> large one perhaps followed by some small ones in the opposite direction.
Schlumpf? Which probably makes things even more interesting than usual.
Kim.
--
Peter Clinch
Mar 17, 2019, 8:37:15 PM3/17/19
to
On 14/03/2019 16:44, Alan Braggins wrote:
> The idea of combining a Rohloff and Schlumpf has come up before in this
> group, but I don't think I've seen it actually being done.
Google-Fu powers back, at least as far as a pic...
> The idea of combining a Rohloff and Schlumpf has come up before in this
> group, but I don't think I've seen it actually being done.
http://www.kinetics-online.co.uk/assets/images/853_02_small.jpg
--
Peter Clinch Medical Physics IT Officer
NHS Tayside & Univ. of Dundee Ninewells Hospital & Med. School
Tel 44 1382 660111 ext. 33637 Dundee DD1 9SY Scotland UK
net p.j.c...@dundee.ac.uk http://medphys.dundee.ac.uk/~pjclinch/
Peter Clinch
Mar 17, 2019, 8:37:38 PM3/17/19
to
On 14/03/2019 16:44, Alan Braggins wrote:
> The idea of combining a Rohloff and Schlumpf has come up before in this
> group, but I don't think I've seen it actually being done.
Ben "Kinetics" Cooper definitely did one years ago, though my Google-Fu
> group, but I don't think I've seen it actually being done.
is not presently sharp enough to find it. Can't remember which Schlumpf
it was either.
Pete.
Tosspot
Mar 18, 2019, 2:04:41 AM3/18/19
to
On 3/15/19 3:53 PM, Peter Clinch wrote:
> On 14/03/2019 16:44, Alan Braggins wrote:
>> The idea of combining a Rohloff and Schlumpf has come up before in this
>> group, but I don't think I've seen it actually being done.
>
> Google-Fu powers back, at least as far as a pic...
>
> http://www.kinetics-online.co.uk/assets/images/853_02_small.jpg
My eyes! MY EYES!!!
> On 14/03/2019 16:44, Alan Braggins wrote:
>> The idea of combining a Rohloff and Schlumpf has come up before in this
>> group, but I don't think I've seen it actually being done.
>
> Google-Fu powers back, at least as far as a pic...
>
> http://www.kinetics-online.co.uk/assets/images/853_02_small.jpg
Rob Morley
Mar 19, 2019, 12:02:09 PM3/19/19
to
On Sun, 17 Mar 2019 23:22:05 +0000
Kim Wall <k...@ductilebiscuit.net> wrote:
> Surely on a tandem the stoker would be in charge of shifting the
> Schlumpf? Which probably makes things even more interesting than
> usual.
>
That depends on the tandem - mine is currently set up with a
Kim Wall <k...@ductilebiscuit.net> wrote:
> Surely on a tandem the stoker would be in charge of shifting the
> Schlumpf? Which probably makes things even more interesting than
> usual.
>
freewheeling stoker chainset so the drive comes from the front.
Rob Morley
Mar 19, 2019, 12:10:50 PM3/19/19
to
makes me think "I wouldn't do it like that"; remarkably the rear rack is
level. I'm not a fan of triple-triangle frames when it's done as a
cosmetic feature (they're OK when that's the best way to achieve a
sensible seat stay placement, as with some curved seat tube short
wheel-base frames). Also not a fan of straight tapered forks.
The handlebar clutter isn't seemly but I've used similar arrangements
and they do serve a valid functional purpose. It will look less bad
when it's covered in black tape.
Tosspot
Mar 19, 2019, 2:40:26 PM3/19/19
to
dropout, frame. Oh, and it's sick green!
Nick Maclaren
Mar 19, 2019, 4:16:46 PM3/19/19
to
In article <JOOdnYrG-4YXqgzB...@giganews.com>,
Well, here are some links to mine. The only reason I have a tensioner
is because I have rear suspension - _I would much rather not have it
and the problems it causes.
https://i.imgur.com/DcxuqWT.jpg
https://i.imgur.com/PUFa0K1.jpg
https://i.imgur.com/3DCR9TD.jpg
Regards,
Nick Maclaren.
is because I have rear suspension - _I would much rather not have it
and the problems it causes.
https://i.imgur.com/DcxuqWT.jpg
https://i.imgur.com/PUFa0K1.jpg
https://i.imgur.com/3DCR9TD.jpg
Regards,
Nick Maclaren.
Tosspot
Mar 20, 2019, 2:04:23 AM3/20/19
to
under the seat, which looked neater and gave a good chain sprocket
interface,
Nick Maclaren
Mar 20, 2019, 6:23:03 AM3/20/19
to
In article <NOydnSmzP8ZBSgzB...@giganews.com>,
removing and replacing chains, cleaning the complex device, and (not
so much on the trike) getting undergrowth tangles in it. If it were
underneath the seat, then undergrowth WOULD be a problem!
What I really want is a full chaincase :-(
Regards,
Nick Maclaren.
Tosspot <Frank...@gmail.com> wrote:
>
>The chain tensioner on my Anthrotech was a derailleur affair but hidden
>under the seat, which looked neater and gave a good chain sprocket
>interface,
It's not the appearance that causes trouble, but it's the hassle of
>
>The chain tensioner on my Anthrotech was a derailleur affair but hidden
>under the seat, which looked neater and gave a good chain sprocket
>interface,
removing and replacing chains, cleaning the complex device, and (not
so much on the trike) getting undergrowth tangles in it. If it were
underneath the seat, then undergrowth WOULD be a problem!
What I really want is a full chaincase :-(
Regards,
Nick Maclaren.
David Damerell
Mar 20, 2019, 7:17:51 AM3/20/19
to
Quoting Nick Maclaren <nm...@cam.ac.uk>:
I don't know your exact mass, of course. I suppose you can simply refrain
from doing so in low range.
--
David Damerell <dame...@chiark.greenend.org.uk> Distortion Field!
Today is First Gouday, March.
Tomorrow will be First Chedday, March - a public holiday.
>Alan Braggins <ar...@chiark.greenend.org.uk> wrote:
>>(http://www.schlumpf.ch/hp/schlumpf/faq.getriebe.engl.htm#C does warn
>>"For a combination with a Rohloff hub (not recommended by Rohloff, as
>>torque coming from the mountain-drive can exceed limitation of entry
>>torque of the Rohloff hub) ...."
>It can. However, to exceed the 100 nm at the hub, I would have to
>push 65 Kg on the pedal - which, even at a cadence of 40 RPM, would
>be 260 watts.
Surely to temporarily push 65kg on the pedal you just have to stand on it?
>>(http://www.schlumpf.ch/hp/schlumpf/faq.getriebe.engl.htm#C does warn
>>"For a combination with a Rohloff hub (not recommended by Rohloff, as
>>torque coming from the mountain-drive can exceed limitation of entry
>>torque of the Rohloff hub) ...."
>It can. However, to exceed the 100 nm at the hub, I would have to
>push 65 Kg on the pedal - which, even at a cadence of 40 RPM, would
>be 260 watts.
I don't know your exact mass, of course. I suppose you can simply refrain
from doing so in low range.
--
David Damerell <dame...@chiark.greenend.org.uk> Distortion Field!
Today is First Gouday, March.
Tomorrow will be First Chedday, March - a public holiday.
Nick Maclaren
Mar 20, 2019, 10:32:42 AM3/20/19
to
In article <+6o*B4...@news.chiark.greenend.org.uk>,
handlebars - but it's a recumbent trike! Even so, while I could
overload it, if I tried, avoiding doing so isn't hard. At 71, I can
sustain 135 watts for (say) 20 minutes, and that's my burst mode for
normal riding.
Furthermore 100 nm (and, actually, I think that it's 120 nm) is
50 Kg on the road in my bottom gear, and I have that much on the
rear wheel only when fully laden for touring. It would slip first
on the sort of roads I ride on, and does, at MUCH lower forces.
Realistically, I can't see much point in a Mountain Drive as well as
a Rohloff for bicycles, because it implies a range of speeds at which
you can balance and pedal of 20:1, assuming a cadence range of 1.5:1.
That's pretty rare.
Regards,
Nick Maclaren.
David Damerell <dame...@chiark.greenend.org.uk> wrote:
>>
>>>(http://www.schlumpf.ch/hp/schlumpf/faq.getriebe.engl.htm#C does warn
>>>"For a combination with a Rohloff hub (not recommended by Rohloff, as
>>>torque coming from the mountain-drive can exceed limitation of entry
>>>torque of the Rohloff hub) ...."
>>It can. However, to exceed the 100 nm at the hub, I would have to
>>push 65 Kg on the pedal - which, even at a cadence of 40 RPM, would
>>be 260 watts.
>
>Surely to temporarily push 65kg on the pedal you just have to stand on it?
>I don't know your exact mass, of course. I suppose you can simply refrain
>from doing so in low range.
I am 80+ Kg, and could still push 120+ Kg by pulling up on the
>>
>>>(http://www.schlumpf.ch/hp/schlumpf/faq.getriebe.engl.htm#C does warn
>>>"For a combination with a Rohloff hub (not recommended by Rohloff, as
>>>torque coming from the mountain-drive can exceed limitation of entry
>>>torque of the Rohloff hub) ...."
>>It can. However, to exceed the 100 nm at the hub, I would have to
>>push 65 Kg on the pedal - which, even at a cadence of 40 RPM, would
>>be 260 watts.
>
>Surely to temporarily push 65kg on the pedal you just have to stand on it?
>I don't know your exact mass, of course. I suppose you can simply refrain
>from doing so in low range.
handlebars - but it's a recumbent trike! Even so, while I could
overload it, if I tried, avoiding doing so isn't hard. At 71, I can
sustain 135 watts for (say) 20 minutes, and that's my burst mode for
normal riding.
Furthermore 100 nm (and, actually, I think that it's 120 nm) is
50 Kg on the road in my bottom gear, and I have that much on the
rear wheel only when fully laden for touring. It would slip first
on the sort of roads I ride on, and does, at MUCH lower forces.
Realistically, I can't see much point in a Mountain Drive as well as
a Rohloff for bicycles, because it implies a range of speeds at which
you can balance and pedal of 20:1, assuming a cadence range of 1.5:1.
That's pretty rare.
Regards,
Nick Maclaren.
Ian Jackson
Mar 20, 2019, 8:34:57 PM3/20/19
to
In article <+6o*B4...@news.chiark.greenend.org.uk>,
David Damerell <dame...@chiark.greenend.org.uk> wrote:
David Damerell <dame...@chiark.greenend.org.uk> wrote:
>Quoting Nick Maclaren <nm...@cam.ac.uk>:
>>It can. However, to exceed the 100 nm at the hub, I would have to
>>push 65 Kg on the pedal - which, even at a cadence of 40 RPM, would
>>be 260 watts.
>
>Surely to temporarily push 65kg on the pedal you just have to stand on it?
>I don't know your exact mass, of course. I suppose you can simply refrain
>from doing so in low range.
Thinking about wattage is not really useful when trying to estimate
>>It can. However, to exceed the 100 nm at the hub, I would have to
>>push 65 Kg on the pedal - which, even at a cadence of 40 RPM, would
>>be 260 watts.
>
>Surely to temporarily push 65kg on the pedal you just have to stand on it?
>I don't know your exact mass, of course. I suppose you can simply refrain
>from doing so in low range.
the peak force a rider can impose on the system. The maximum
available power output depends far too much on the time period over
which it is measured.
The answer will be quite different when the limiting factors are (from
longest to shortest duration) (i) glycogen reserves (ie, the bonk)
(ii) oxygen transport (iii) anaerobic energy stores (iv) mechanical
travel of the joints during a single power stroke (v) available peak
force from the muscles in use.
The answers in cases (iv) and (v) depend massively on the speed as
well. When asking about `maximum power' one is implicitly specifying
that the action takes place at the speed where maximum power is
available. But of course if what one really wants is an estimate of
maximum force, that is not right. Maximum peak force is available at
roughly zero speed (ie negligible output power).
Here we are indeed interested in peak force, even if it is only
exerted for a few tens of milliseconds. I'm not sure how to estimate
peak force, but let me have a go:
An obvious lower bound for someone who can climb stairs is the ability
to accelerate their own body weight upwards with the muscles of both
legs, giving a minimum force per leg of half their body weight. In
practice I think this is a very loose bound; for example, the
mechanics of stair climbing strongly favour doing most of the work
with one leg.
I guess one could look at weightlifting. Wikipedia tells me that a
"squat" is a weightlifting exercise involving starting with legs bent
and straightening the legs, while a weight is held at the shoulders.
The world record is 575kg. IDK how much the lifter (Jonas Rantanen)
weighed but let's say they lifted 75kg of their own mass too giving
650kg. But that's for both legs, so that gives us 325kg per leg.
Incidentally, the lift part of a squat is presumably completed in much
less than a second. 6500N / 1s = 6500W, but probably peak power is
much more because up to a point it'll be easier to do it faster rather
than slower. That just goes to show how useless power figures are
over very short durations.
Of course that 325kg per leg is a world record. Random internet
search suggest that the average man can do a squat of about 65kg but
presumably they are lifting most of their weight too, so let us say
140kg. So maybe 70kg per leg ?
Overall that seems to suggest that 65kg from one leg would be within
many people's capacity, but perhaps not most. As for Nick personally,
I don't think it can be answered on paper. This analysis has
certainly failed to rule out that he could exceed the hub's spec. I
would advise Nick to be gentle with it :-).
--
Ian Jackson <ijac...@chiark.greenend.org.uk> These opinions are my own.
If I emailed you from an address @fyvzl.net or @evade.org.uk, that is
a private address which bypasses my fierce spamfilter.
Ian Jackson
Mar 20, 2019, 8:35:10 PM3/20/19
to
In article <q6rims$blv$1...@dont-email.me>, Nick Maclaren <nm...@cam.ac.uk> wrote:
>Well, here are some links to mine. The only reason I have a tensioner
>is because I have rear suspension - _I would much rather not have it
>and the problems it causes.
>
>https://i.imgur.com/DcxuqWT.jpg
>https://i.imgur.com/PUFa0K1.jpg
>https://i.imgur.com/3DCR9TD.jpg
Ooh, thanks for the pics. Fascinating.
>Well, here are some links to mine. The only reason I have a tensioner
>is because I have rear suspension - _I would much rather not have it
>and the problems it causes.
>
>https://i.imgur.com/DcxuqWT.jpg
>https://i.imgur.com/PUFa0K1.jpg
>https://i.imgur.com/3DCR9TD.jpg
David Damerell
Mar 20, 2019, 9:09:34 PM3/20/19
to
Yes, that seems even worse, especially since I guess that shifting it
without an interruption in pedalling is a bit of a ninja skill. (Sure, one
wants to ease off with derailleur drive, but that's not so bad...)
--
David Damerell <dame...@chiark.greenend.org.uk> flcl?
Today is Gorgonzoladay, March - a weekend.
Tomorrow will be Second Gloucesterday, March.
Rob Morley
Mar 20, 2019, 11:57:28 PM3/20/19
to
On Tue, 19 Mar 2019 20:16:28 -0000 (UTC)
n...@wheeler.UUCP (Nick Maclaren) wrote:
> The only reason I have a tensioner
> is because I have rear suspension - _I would much rather not have it
> and the problems it causes.
Replace the urethane cushions with nylon or aluminium?
n...@wheeler.UUCP (Nick Maclaren) wrote:
> The only reason I have a tensioner
> is because I have rear suspension - _I would much rather not have it
> and the problems it causes.
Nick Maclaren
Mar 21, 2019, 5:05:09 AM3/21/19
to
In article <20190321035711.3d70b03b@Mars>,
I dislike. But, with that design of chain run, something is needed
even with pure hub gears.
Regards,
Nick Maclaren.
Rob Morley <nos...@ntlworld.com> wrote:
>
>> The only reason I have a tensioner
>> is because I have rear suspension - _I would much rather not have it
>> and the problems it causes.
>
>Replace the urethane cushions with nylon or aluminium?
Sorry - I was unclear. I like the rear suspension - it's the tensioner
>
>> The only reason I have a tensioner
>> is because I have rear suspension - _I would much rather not have it
>> and the problems it causes.
>
>Replace the urethane cushions with nylon or aluminium?
I dislike. But, with that design of chain run, something is needed
even with pure hub gears.
Regards,
Nick Maclaren.
Nick Maclaren
Mar 21, 2019, 5:18:20 AM3/21/19
to
In article <B7f*uW...@news.chiark.greenend.org.uk>,
push, for which I am pretty sure it IS reliable. And, because I pedal
pretty smoothly (until I run out of gears) and at a fairly consistent
power output, I can easily avoid putting much more peak force on, and
a factor of two margin is reasonably safe.
Yes, I used to start off a lot more aggressively than I do, but I was
40 years younger and had a good 40% more aerobic capacity. That's
important, because pushing yourself very hard even for ten seconds
reduces your ability to deliver power steadily for a long time after.
For the reasons you explained - depletion of energy sources.
Even now, I can climb stairs or steep hills with a 25 Kg pack, which
is an all-up weight of c. 110 Kg, and am sure that I could push 150 Kg
and probably 200 Kg, instantaneously. But it's not something that one
does by accident! If I attempted to force my gears with my lock on the
rear wheel, I could destroy the Rohloff - but why would I?
Regards,
Nick Maclaren.
Ian Jackson <ijac...@chiark.greenend.org.uk> wrote:
>In article <+6o*B4...@news.chiark.greenend.org.uk>,
>David Damerell <dame...@chiark.greenend.org.uk> wrote:
>>
>>>It can. However, to exceed the 100 nm at the hub, I would have to
>>>push 65 Kg on the pedal - which, even at a cadence of 40 RPM, would
>>>be 260 watts.
>>
>>Surely to temporarily push 65kg on the pedal you just have to stand on it?
>>I don't know your exact mass, of course. I suppose you can simply refrain
>>from doing so in low range.
>
>Thinking about wattage is not really useful when trying to estimate
>the peak force a rider can impose on the system. The maximum
>available power output depends far too much on the time period over
>which it is measured.
Oh, I agree there. What I am using it for is to estimate my normal
>In article <+6o*B4...@news.chiark.greenend.org.uk>,
>David Damerell <dame...@chiark.greenend.org.uk> wrote:
>>
>>>It can. However, to exceed the 100 nm at the hub, I would have to
>>>push 65 Kg on the pedal - which, even at a cadence of 40 RPM, would
>>>be 260 watts.
>>
>>Surely to temporarily push 65kg on the pedal you just have to stand on it?
>>I don't know your exact mass, of course. I suppose you can simply refrain
>>from doing so in low range.
>
>Thinking about wattage is not really useful when trying to estimate
>the peak force a rider can impose on the system. The maximum
>available power output depends far too much on the time period over
>which it is measured.
push, for which I am pretty sure it IS reliable. And, because I pedal
pretty smoothly (until I run out of gears) and at a fairly consistent
power output, I can easily avoid putting much more peak force on, and
a factor of two margin is reasonably safe.
Yes, I used to start off a lot more aggressively than I do, but I was
40 years younger and had a good 40% more aerobic capacity. That's
important, because pushing yourself very hard even for ten seconds
reduces your ability to deliver power steadily for a long time after.
For the reasons you explained - depletion of energy sources.
Even now, I can climb stairs or steep hills with a 25 Kg pack, which
is an all-up weight of c. 110 Kg, and am sure that I could push 150 Kg
and probably 200 Kg, instantaneously. But it's not something that one
does by accident! If I attempted to force my gears with my lock on the
rear wheel, I could destroy the Rohloff - but why would I?
Regards,
Nick Maclaren.
Rob Morley
Mar 21, 2019, 1:57:06 PM3/21/19
to
been asleep by then. Would it be less annoying if it was attached under
the boom?
Nick Maclaren
Mar 21, 2019, 2:28:46 PM3/21/19
to
In article <20190321175651.0dc10f8b@Mars>,
off, but it would catch undergrowth and would be at much more risk of
damage.
It could be avoided entirely, but not without a major redesign and
some minor disadvantages (which wouldn't affect me, but would some
other people).
Regards,
Nick Maclaren.
Rob Morley <nos...@ntlworld.com> wrote:
>
>> >Replace the urethane cushions with nylon or aluminium?
>>
>> Sorry - I was unclear. I like the rear suspension - it's the
>> tensioner I dislike. But, with that design of chain run, something
>> is needed even with pure hub gears.
>>
>Ah, I should probably have read it that way in the first place, or
>been asleep by then. Would it be less annoying if it was attached under
>the boom?
Probably more so. It wouldn't get in the way of taking the rear wheel
>
>> >Replace the urethane cushions with nylon or aluminium?
>>
>> Sorry - I was unclear. I like the rear suspension - it's the
>> tensioner I dislike. But, with that design of chain run, something
>> is needed even with pure hub gears.
>>
>Ah, I should probably have read it that way in the first place, or
>been asleep by then. Would it be less annoying if it was attached under
>the boom?
off, but it would catch undergrowth and would be at much more risk of
damage.
It could be avoided entirely, but not without a major redesign and
some minor disadvantages (which wouldn't affect me, but would some
other people).
Regards,
Nick Maclaren.
Ian Jackson
Mar 21, 2019, 6:28:56 PM3/21/19
to
In article <q6vksf$573$1...@dont-email.me>, Nick Maclaren <nm...@cam.ac.uk> wrote:
>Oh, I agree there. What I am using it for is to estimate my normal
>push, for which I am pretty sure it IS reliable.
Right.
>Oh, I agree there. What I am using it for is to estimate my normal
>push, for which I am pretty sure it IS reliable.
> And, because I pedal pretty smoothly (until I run out of gears) and
>at a fairly consistent power output, I can easily avoid putting much
>more peak force on, and a factor of two margin is reasonably safe.
>Even now, I can climb stairs or steep hills with a 25 Kg pack, which
>is an all-up weight of c. 110 Kg, and am sure that I could push 150 Kg
>and probably 200 Kg, instantaneously. But it's not something that one
>does by accident! If I attempted to force my gears with my lock on the
>rear wheel, I could destroy the Rohloff - but why would I?
give a good shove when startled or distracted. (Ie, "by accident" if
you want to put it like that.) Best of luck with it anyway !
Nick Maclaren
Mar 22, 2019, 11:31:19 AM3/22/19
to
In article <XVu*8N...@news.chiark.greenend.org.uk>,
are, and/or the fact that I am an experienced hub gear user! My
normal push is in the 10-20Kg range, and I never go above 30 Kg
nowadays, even climbing very short, steep slopes. It's always much
easier to change down, and doesn't have the problem with rolling to
a halt in the dead spot. The chances of me pushing 60+ Kg in a fit
of abstraction isn't high!
The same would not be true for you, because you generate a lot more
power (twice as much?) I have today climbed Chapel Hill in a mere
8 minutes (admittedly with 117 Kg all-up) - even allowing for all
the inefficiencies, that's only 125 watts.
Regards,
Nick Maclaren.
Ian Jackson <ijac...@chiark.greenend.org.uk> wrote:
>
>>Even now, I can climb stairs or steep hills with a 25 Kg pack, which
>>is an all-up weight of c. 110 Kg, and am sure that I could push 150 Kg
>>and probably 200 Kg, instantaneously. But it's not something that one
>>does by accident! If I attempted to force my gears with my lock on the
>>rear wheel, I could destroy the Rohloff - but why would I?
>
>Well, maybe you have better self-control than I have. I might easily
>give a good shove when startled or distracted. (Ie, "by accident" if
>you want to put it like that.) Best of luck with it anyway !
Not really - you are forgetting how much less powerful I am than you
>
>>Even now, I can climb stairs or steep hills with a 25 Kg pack, which
>>is an all-up weight of c. 110 Kg, and am sure that I could push 150 Kg
>>and probably 200 Kg, instantaneously. But it's not something that one
>>does by accident! If I attempted to force my gears with my lock on the
>>rear wheel, I could destroy the Rohloff - but why would I?
>
>Well, maybe you have better self-control than I have. I might easily
>give a good shove when startled or distracted. (Ie, "by accident" if
>you want to put it like that.) Best of luck with it anyway !
are, and/or the fact that I am an experienced hub gear user! My
normal push is in the 10-20Kg range, and I never go above 30 Kg
nowadays, even climbing very short, steep slopes. It's always much
easier to change down, and doesn't have the problem with rolling to
a halt in the dead spot. The chances of me pushing 60+ Kg in a fit
of abstraction isn't high!
The same would not be true for you, because you generate a lot more
power (twice as much?) I have today climbed Chapel Hill in a mere
8 minutes (admittedly with 117 Kg all-up) - even allowing for all
the inefficiencies, that's only 125 watts.
Regards,
Nick Maclaren.
Ian Jackson
Mar 22, 2019, 2:01:55 PM3/22/19
to
In article <q72v3o$85n$1...@dont-email.me>, Nick Maclaren <nm...@cam.ac.uk> wrote:
>In article <XVu*8N...@news.chiark.greenend.org.uk>,
>Ian Jackson <ijac...@chiark.greenend.org.uk> wrote:
>>Well, maybe you have better self-control than I have. I might easily
>>give a good shove when startled or distracted. (Ie, "by accident" if
>>you want to put it like that.) Best of luck with it anyway !
>
>Not really - you are forgetting how much less powerful I am than you
>are, and/or the fact that I am an experienced hub gear user!
I think it's more that my usual style of movement is ... very brisk
>In article <XVu*8N...@news.chiark.greenend.org.uk>,
>Ian Jackson <ijac...@chiark.greenend.org.uk> wrote:
>>Well, maybe you have better self-control than I have. I might easily
>>give a good shove when startled or distracted. (Ie, "by accident" if
>>you want to put it like that.) Best of luck with it anyway !
>
>Not really - you are forgetting how much less powerful I am than you
>are, and/or the fact that I am an experienced hub gear user!
and dynamic. I guess you are more thoughful and measured. You
probably never randomly careened off doorframes either...
>The same would not be true for you, because you generate a lot more
>power (twice as much?) I have today climbed Chapel Hill in a mere
>8 minutes (admittedly with 117 Kg all-up) - even allowing for all
>the inefficiencies, that's only 125 watts.
on very steep a hike in Taiwan, ~210W for me (aerobic). But as you
say it seems very likely that you would have no difficulty breaking it
if you gave it a good shove. The part where your mileage varies from
mine is, I think, that I would need constant concentration not to
break it in a fit of absent-mindedness...
Nick Maclaren
Mar 22, 2019, 2:47:30 PM3/22/19
to
ws.chiark.greenws.chiark.greenws.chiark.greenws.chiark.greenIn article <NPm*Hl...@news.chiark.greenend.org.uk>,
nudges me. That's a matter of age - at 71, I am less brisk and
dynamic than I was, and getting less so.
>>The same would not be true for you, because you generate a lot more
>>power (twice as much?) I have today climbed Chapel Hill in a mere
>>8 minutes (admittedly with 117 Kg all-up) - even allowing for all
>>the inefficiencies, that's only 125 watts.
>
>FTR guessing from online calculators and also my stair climbing speed
>on very steep a hike in Taiwan, ~210W for me (aerobic). But as you
>say it seems very likely that you would have no difficulty breaking it
>if you gave it a good shove. The part where your mileage varies from
>mine is, I think, that I would need constant concentration not to
>break it in a fit of absent-mindedness...
I might, too, if I used it on an upright and could balance at the
very low speeds where I would need low range. But a recumbent trike
is very different in this respect - plus the fact that mashing below
40 RPM simply doesn't work with an 8" bottom gear (you roll to a halt
in the dead spot)!
But it's a really esoteric requirement for a bicycle, as distinct
from a tricycle, as the ratio of the top pedalling speed to the
lowest balance speed is rarely that great.
Regards,
Nick Maclaren.
Ian Jackson <ijac...@chiark.greenend.org.uk> wrote:
>
>I think it's more that my usual style of movement is ... very brisk
>and dynamic. I guess you are more thoughful and measured. You
>probably never randomly careened off doorframes either...
Frequently, but nowadays mainly because I lose balance or somebody
>
>I think it's more that my usual style of movement is ... very brisk
>and dynamic. I guess you are more thoughful and measured. You
>probably never randomly careened off doorframes either...
nudges me. That's a matter of age - at 71, I am less brisk and
dynamic than I was, and getting less so.
>>The same would not be true for you, because you generate a lot more
>>power (twice as much?) I have today climbed Chapel Hill in a mere
>>8 minutes (admittedly with 117 Kg all-up) - even allowing for all
>>the inefficiencies, that's only 125 watts.
>
>FTR guessing from online calculators and also my stair climbing speed
>on very steep a hike in Taiwan, ~210W for me (aerobic). But as you
>say it seems very likely that you would have no difficulty breaking it
>if you gave it a good shove. The part where your mileage varies from
>mine is, I think, that I would need constant concentration not to
>break it in a fit of absent-mindedness...
very low speeds where I would need low range. But a recumbent trike
is very different in this respect - plus the fact that mashing below
40 RPM simply doesn't work with an 8" bottom gear (you roll to a halt
in the dead spot)!
But it's a really esoteric requirement for a bicycle, as distinct
from a tricycle, as the ratio of the top pedalling speed to the
lowest balance speed is rarely that great.
Regards,
Nick Maclaren.
Zebee Johnstone
Mar 22, 2019, 4:09:42 PM3/22/19
to
In uk.rec.cycling.moderated on Fri, 22 Mar 2019 15:31:04 -0000 (UTC)
spin enough on hills to make it feel OK. If I upped the cadence to
more than was quite comfortable it felt mushy and awful.
On the other hand... My left knee is now saying (quite reasonably)
"You remember when you smashed me into the tarmac at 60kmh? I do...."
and spinning shuts it up. So up hills I do a lot less low speed
pushing even on the trike where balance is not an issue.
Dunno if it would be enough to go back to the MD but as I'm not going
to be touring for the forseeable future the question does not arise.
Zebee
Nick Maclaren <n...@wheeler.UUCP> wrote:
>
> Not really - you are forgetting how much less powerful I am than you
> are, and/or the fact that I am an experienced hub gear user! My
> normal push is in the 10-20Kg range, and I never go above 30 Kg
> nowadays, even climbing very short, steep slopes. It's always much
> easier to change down, and doesn't have the problem with rolling to
> a halt in the dead spot. The chances of me pushing 60+ Kg in a fit
> of abstraction isn't high!
>
So much is habit... It's why I remvoed the mountain drive: I couldn't
>
> Not really - you are forgetting how much less powerful I am than you
> are, and/or the fact that I am an experienced hub gear user! My
> normal push is in the 10-20Kg range, and I never go above 30 Kg
> nowadays, even climbing very short, steep slopes. It's always much
> easier to change down, and doesn't have the problem with rolling to
> a halt in the dead spot. The chances of me pushing 60+ Kg in a fit
> of abstraction isn't high!
>
spin enough on hills to make it feel OK. If I upped the cadence to
more than was quite comfortable it felt mushy and awful.
On the other hand... My left knee is now saying (quite reasonably)
"You remember when you smashed me into the tarmac at 60kmh? I do...."
and spinning shuts it up. So up hills I do a lot less low speed
pushing even on the trike where balance is not an issue.
Dunno if it would be enough to go back to the MD but as I'm not going
to be touring for the forseeable future the question does not arise.
Zebee
Nick Maclaren
Mar 22, 2019, 5:22:48 PM3/22/19
to
In article <slrnq9ag7n...@gmail.com>,
necessarily travel faster, and necessarily use more power. Where
does it come from? I use the low range more-or-less only for hills
that I can't physically pedal up without.
Regards,
Nick Maclaren.
Zebee Johnstone <zeb...@gmail.com> wrote:
>
>On the other hand... My left knee is now saying (quite reasonably)
>"You remember when you smashed me into the tarmac at 60kmh? I do...."
>and spinning shuts it up. So up hills I do a lot less low speed
>pushing even on the trike where balance is not an issue.
I don't understand. If you spin faster in your bottom gear, you
>
>On the other hand... My left knee is now saying (quite reasonably)
>"You remember when you smashed me into the tarmac at 60kmh? I do...."
>and spinning shuts it up. So up hills I do a lot less low speed
>pushing even on the trike where balance is not an issue.
necessarily travel faster, and necessarily use more power. Where
does it come from? I use the low range more-or-less only for hills
that I can't physically pedal up without.
Regards,
Nick Maclaren.
Zebee Johnstone
Mar 23, 2019, 5:44:43 AM3/23/19
to
In uk.rec.cycling.moderated on Fri, 22 Mar 2019 21:22:36 -0000 (UTC)
I'm not using an MD. I"m not even using the small ring on my triple
most of the time on the 2 wheeler. The trike has a motor which has a
torque sensor that prefers a cadence of 80 or so anyway.
On the 2 wheeler or the Brompton I am using lower gears on hills than
I used to.
Dunno about more power, it certainly means I puff more.
Zebee
most of the time on the 2 wheeler. The trike has a motor which has a
torque sensor that prefers a cadence of 80 or so anyway.
On the 2 wheeler or the Brompton I am using lower gears on hills than
I used to.
Dunno about more power, it certainly means I puff more.
Zebee
Nick Maclaren
Mar 23, 2019, 7:37:01 AM3/23/19
to
In article <slrnq9bvvq...@gmail.com>,
your total power (including motor) will be at least 350 watts, quite
probably significantly more.
It is ridiculous that motors are optimised for high cadences, as very,
very few people who need (or, probably, use them) every ride higher
than 60 RPM and quite a lot stay below 50 RPM. For damn good reasons,
too, but I have posted that before :-(
>Dunno about more power, it certainly means I puff more.
You are generating more power! You can get a pretty accurate estimate
of your power from hill climbing, at least with a hill steep enough
to slow you right down.
Regards,
Nick Maclaren.
Zebee Johnstone <zeb...@gmail.com> wrote:
>>>
>>>On the other hand... My left knee is now saying (quite reasonably)
>>>"You remember when you smashed me into the tarmac at 60kmh? I do...."
>>>and spinning shuts it up. So up hills I do a lot less low speed
>>>pushing even on the trike where balance is not an issue.
>>
>> I don't understand. If you spin faster in your bottom gear, you
>> necessarily travel faster, and necessarily use more power. Where
>> does it come from? I use the low range more-or-less only for hills
>> that I can't physically pedal up without.
>
>I'm not using an MD. I"m not even using the small ring on my triple
>most of the time on the 2 wheeler. The trike has a motor which has a
>torque sensor that prefers a cadence of 80 or so anyway.
Ah! That makes a big difference. Even if you are my sort of power,
>>>
>>>On the other hand... My left knee is now saying (quite reasonably)
>>>"You remember when you smashed me into the tarmac at 60kmh? I do...."
>>>and spinning shuts it up. So up hills I do a lot less low speed
>>>pushing even on the trike where balance is not an issue.
>>
>> I don't understand. If you spin faster in your bottom gear, you
>> necessarily travel faster, and necessarily use more power. Where
>> does it come from? I use the low range more-or-less only for hills
>> that I can't physically pedal up without.
>
>I'm not using an MD. I"m not even using the small ring on my triple
>most of the time on the 2 wheeler. The trike has a motor which has a
>torque sensor that prefers a cadence of 80 or so anyway.
your total power (including motor) will be at least 350 watts, quite
probably significantly more.
It is ridiculous that motors are optimised for high cadences, as very,
very few people who need (or, probably, use them) every ride higher
than 60 RPM and quite a lot stay below 50 RPM. For damn good reasons,
too, but I have posted that before :-(
>Dunno about more power, it certainly means I puff more.
of your power from hill climbing, at least with a hill steep enough
to slow you right down.
Regards,
Nick Maclaren.
David Damerell
Mar 25, 2019, 1:34:52 PM3/25/19
to
Quoting Ian Jackson <ijac...@chiark.greenend.org.uk>:
>David Damerell <dame...@chiark.greenend.org.uk> wrote:
>>Quoting Nick Maclaren <nm...@cam.ac.uk>:
>>>It can. However, to exceed the 100 nm at the hub, I would have to
>>>push 65 Kg on the pedal - which, even at a cadence of 40 RPM, would
>>>be 260 watts.
>>Surely to temporarily push 65kg on the pedal you just have to stand on
>>it?
>David Damerell <dame...@chiark.greenend.org.uk> wrote:
>>Quoting Nick Maclaren <nm...@cam.ac.uk>:
>>>It can. However, to exceed the 100 nm at the hub, I would have to
>>>push 65 Kg on the pedal - which, even at a cadence of 40 RPM, would
>>>be 260 watts.
>>Surely to temporarily push 65kg on the pedal you just have to stand on
>>it?
>Overall that seems to suggest that 65kg from one leg would be within
>many people's capacity, but perhaps not most.
I think you are overanalysing; I think most people can do this because
>many people's capacity, but perhaps not most.
most people weigh >65kg (average adult woman in the UK is about 70kg) and
can climb stairs, which if you don't haul yourself up with the banister
involves lifting your entire weight by straightening one leg.
On an upright (which I appreciate Nick has not got) it is surely common to
mount by putting a leg over, putting that leg's foot on the pedal, and
shoving hard enough to lift yourself up to get into the saddle. It seems
almost inevitable that such an operation pushes with a force similar to
the rider's weight, and I expect an ordinarily fit and healthy person to
be able to mount a bicycle like that.
--
David Damerell <dame...@chiark.greenend.org.uk>
And now, a seemingly inexplicable shot of a passing train.
Today is Second Leicesterday, March.
Tomorrow will be Second Brieday, March.
Nick Maclaren
Mar 25, 2019, 3:06:59 PM3/25/19
to
In article <cmc*RL...@news.chiark.greenend.org.uk>,
I know that I can push 110 Kg, and can only guess how much more.
Overloading a Rohloff by using a Mountain Drive is assuredly something
that can be done, and I would have to take GREAT care if I had one on
my roadster - but there would be no point, as I can't balance at the
very low speeds involved!
I still think that the combination is excellent on a recumbent trike,
almost pointless on an (upright or recumbent) bicycle, and something
I can't decide on an upright trike.
Regards,
Nick Maclaren.
David Damerell <dame...@chiark.greenend.org.uk> wrote:
>
>I think you are overanalysing; I think most people can do this because
>most people weigh >65kg (average adult woman in the UK is about 70kg) and
>can climb stairs, which if you don't haul yourself up with the banister
>involves lifting your entire weight by straightening one leg.
>
>On an upright (which I appreciate Nick has not got) it is surely common to
>mount by putting a leg over, putting that leg's foot on the pedal, and
>shoving hard enough to lift yourself up to get into the saddle. It seems
>almost inevitable that such an operation pushes with a force similar to
>the rider's weight, and I expect an ordinarily fit and healthy person to
>be able to mount a bicycle like that.
Yes, precisely. Since I can climb stairs and hills with heavy pack,
>
>I think you are overanalysing; I think most people can do this because
>most people weigh >65kg (average adult woman in the UK is about 70kg) and
>can climb stairs, which if you don't haul yourself up with the banister
>involves lifting your entire weight by straightening one leg.
>
>On an upright (which I appreciate Nick has not got) it is surely common to
>mount by putting a leg over, putting that leg's foot on the pedal, and
>shoving hard enough to lift yourself up to get into the saddle. It seems
>almost inevitable that such an operation pushes with a force similar to
>the rider's weight, and I expect an ordinarily fit and healthy person to
>be able to mount a bicycle like that.
I know that I can push 110 Kg, and can only guess how much more.
Overloading a Rohloff by using a Mountain Drive is assuredly something
that can be done, and I would have to take GREAT care if I had one on
my roadster - but there would be no point, as I can't balance at the
very low speeds involved!
I still think that the combination is excellent on a recumbent trike,
almost pointless on an (upright or recumbent) bicycle, and something
I can't decide on an upright trike.
Regards,
Nick Maclaren.
Alan Braggins
Mar 26, 2019, 12:35:12 AM3/26/19
to
On 2019-03-15, Peter Clinch <p.j.c...@dundee.ac.uk> wrote:
> On 14/03/2019 16:44, Alan Braggins wrote:
>> The idea of combining a Rohloff and Schlumpf has come up before in this
>> group, but I don't think I've seen it actually being done.
> On 14/03/2019 16:44, Alan Braggins wrote:
>> The idea of combining a Rohloff and Schlumpf has come up before in this
>> group, but I don't think I've seen it actually being done.
>
> Google-Fu powers back, at least as far as a pic...
> http://www.kinetics-online.co.uk/assets/images/853_02_small.jpg
Now that you post that, I had seen it before - I remember the handlebars.
> Google-Fu powers back, at least as far as a pic...
> http://www.kinetics-online.co.uk/assets/images/853_02_small.jpg
Alan Braggins
Mar 26, 2019, 12:35:17 AM3/26/19
to
On 2019-03-16, Zebee Johnstone <zeb...@gmail.com> wrote:
> In uk.rec.cycling.moderated on 14 Mar 2019 20:55:51 +0000 (GMT)
> David Damerell <dame...@chiark.greenend.org.uk> wrote:
>>>previously that you could combine a Schlumpf with a tandem timing chain,
>>>though the Schlumpf FAQ does mention it as possible.
>>
>> It does seem a bit like overkill. I mean, I know as well as anyone you
>> want a very wide gear range on a tandem, but the tandem-and-Rohloff owners
>> I know seem to find it satisfactory.
>
> Anyone come across a non-twistgrip Rohloff?
I've not tried any of them. Gebla Rohbox looks nice, but with a pair of
modified SRAM levers it costs as much as my second hand Rohloff did.
https://www.cyclingabout.com/gebla-rohbox-road-mountain-shifters-with-rohloff-hubs/
Other, even more expensive, electric or hydraulic options exist:
https://www.cyclingabout.com/rohloff-hubs-with-drop-handlebars/
https://www.cyclingabout.com/2017-bpod-pshr-trigger-brings-hydraulic-shifting-to-rohloff-hub/
> In uk.rec.cycling.moderated on 14 Mar 2019 20:55:51 +0000 (GMT)
> David Damerell <dame...@chiark.greenend.org.uk> wrote:
>> Quoting Alan Braggins <ar...@chiark.greenend.org.uk>:
>>>The idea of combining a Rohloff and Schlumpf has come up before in this
>>>group, but I don't think I've seen it actually being done. Nor did I realise
>>>The idea of combining a Rohloff and Schlumpf has come up before in this
>>>previously that you could combine a Schlumpf with a tandem timing chain,
>>>though the Schlumpf FAQ does mention it as possible.
>>
>> It does seem a bit like overkill. I mean, I know as well as anyone you
>> want a very wide gear range on a tandem, but the tandem-and-Rohloff owners
>> I know seem to find it satisfactory.
>
> Anyone come across a non-twistgrip Rohloff?
I've not tried any of them. Gebla Rohbox looks nice, but with a pair of
modified SRAM levers it costs as much as my second hand Rohloff did.
https://www.cyclingabout.com/gebla-rohbox-road-mountain-shifters-with-rohloff-hubs/
Other, even more expensive, electric or hydraulic options exist:
https://www.cyclingabout.com/rohloff-hubs-with-drop-handlebars/
https://www.cyclingabout.com/2017-bpod-pshr-trigger-brings-hydraulic-shifting-to-rohloff-hub/
Alan Braggins
Mar 26, 2019, 12:35:34 AM3/26/19
to
On 2019-03-14, Nick Maclaren <n...@wheeler.UUCP> wrote:
> In article <slrnq8l17...@chiark.greenend.org.uk>,
>
> If you visited me, I could show you.
I might take you up on that sometime. Thanks. (It was your setup that
I was thinking of as "has come up before".)
>>(http://www.schlumpf.ch/hp/schlumpf/faq.getriebe.engl.htm#C does warn
>>"For a combination with a Rohloff hub (not recommended by Rohloff, as
>> torque coming from the mountain-drive can exceed limitation of entry
>> torque of the Rohloff hub) ...."
>
> the trike with the pedals in low range when it rolls backwards downhill.
But that's essential because an instantaneous shock load matters as
well as the sustained power. And the eBay item that triggered my post
was for a tandem, and so that would only be 130W average per rider.
(Also it's an upright bicycle, which I think would make using the full
range harder than on your trike. Though since the listing didn't specify
which model Schlumpf it was, maybe it was a Speed Drive (1:1.65), not
Mountain.)
> Essentially, I use the 20"-100" range with the mountain drive in
> direct drive almost all of the time, and stop and select low range
> only when I get stuck. I am not good at changing the Schlumpf on the
> move, but so what? A bottom gear of 8" enables me to get up 15% with
> a full touring load.
I've just come back from a week in North Wales, which has bigger hills
than I am used to encountering in the Cambridgeshire fens :-)
I already had a triple chainset (30t small), but I did buy a larger range
cassette (34t) and swap on a derailleur that would handle it, and was glad
I did. That wasn't with a touring load though, just day trips.
(I found the top end of the range was relatively pointless in the hills
though, since it turns out I get scared and brake downhill at speeds
less than I can manage on the flat. Maybe more practice....)
> In article <slrnq8l17...@chiark.greenend.org.uk>,
> Alan Braggins <ar...@chiark.greenend.org.uk> wrote:
>>The idea of combining a Rohloff and Schlumpf has come up before in this
>>group, but I don't think I've seen it actually being done. ...
>>The idea of combining a Rohloff and Schlumpf has come up before in this
>
> If you visited me, I could show you.
I might take you up on that sometime. Thanks. (It was your setup that
I was thinking of as "has come up before".)
>>(http://www.schlumpf.ch/hp/schlumpf/faq.getriebe.engl.htm#C does warn
>>"For a combination with a Rohloff hub (not recommended by Rohloff, as
>> torque coming from the mountain-drive can exceed limitation of entry
>> torque of the Rohloff hub) ...."
>
> It can. However, to exceed the 100 nm at the hub, I would have to
> push 65 Kg on the pedal - which, even at a cadence of 40 RPM, would
> be 260 watts. NO chance! The essential thing to avoid is catching
> push 65 Kg on the pedal - which, even at a cadence of 40 RPM, would
> the trike with the pedals in low range when it rolls backwards downhill.
But that's essential because an instantaneous shock load matters as
well as the sustained power. And the eBay item that triggered my post
was for a tandem, and so that would only be 130W average per rider.
(Also it's an upright bicycle, which I think would make using the full
range harder than on your trike. Though since the listing didn't specify
which model Schlumpf it was, maybe it was a Speed Drive (1:1.65), not
Mountain.)
> Essentially, I use the 20"-100" range with the mountain drive in
> direct drive almost all of the time, and stop and select low range
> only when I get stuck. I am not good at changing the Schlumpf on the
> move, but so what? A bottom gear of 8" enables me to get up 15% with
> a full touring load.
I've just come back from a week in North Wales, which has bigger hills
than I am used to encountering in the Cambridgeshire fens :-)
I already had a triple chainset (30t small), but I did buy a larger range
cassette (34t) and swap on a derailleur that would handle it, and was glad
I did. That wasn't with a touring load though, just day trips.
(I found the top end of the range was relatively pointless in the hills
though, since it turns out I get scared and brake downhill at speeds
less than I can manage on the flat. Maybe more practice....)
Alan Braggins
Mar 26, 2019, 12:35:42 AM3/26/19
to
On 2019-03-19, Rob Morley <nos...@ntlworld.com> wrote:
> freewheeling stoker chainset so the drive comes from the front.
The one that started the thread does have the Schlumpf on the rear
bottom bracket. I imagine the Rohloff range is almost always enough,
and Schlumpf changes are rare.
> On Sun, 17 Mar 2019 23:22:05 +0000
> Kim Wall <k...@ductilebiscuit.net> wrote:
>
>> Surely on a tandem the stoker would be in charge of shifting the
>> Schlumpf? Which probably makes things even more interesting than
>> usual.
>>
> That depends on the tandem - mine is currently set up with a
> Kim Wall <k...@ductilebiscuit.net> wrote:
>
>> Surely on a tandem the stoker would be in charge of shifting the
>> Schlumpf? Which probably makes things even more interesting than
>> usual.
>>
> freewheeling stoker chainset so the drive comes from the front.
The one that started the thread does have the Schlumpf on the rear
bottom bracket. I imagine the Rohloff range is almost always enough,
and Schlumpf changes are rare.
Tosspot
Mar 26, 2019, 2:03:33 AM3/26/19
to
simple, a couple of over/under thumb levers with an actuation mechanism
like a classic bell, think a bit of free play before the cogs engage.
This allows the paying out pulley to be free.
Alan Braggins
Apr 9, 2019, 2:25:34 PM4/9/19
to
On 2019-03-14, David Damerell <dame...@chiark.greenend.org.uk> wrote:
> Quoting Alan Braggins <ar...@chiark.greenend.org.uk>:
>>The idea of combining a Rohloff and Schlumpf has come up before in this
>>group, but I don't think I've seen it actually being done. Nor did I realise
>>previously that you could combine a Schlumpf with a tandem timing chain,
>>though the Schlumpf FAQ does mention it as possible.
>
> It does seem a bit like overkill. I mean, I know as well as anyone you
> want a very wide gear range on a tandem, but the tandem-and-Rohloff owners
> I know seem to find it satisfactory.
Playing around with the gearing calculator at http://ritzelrechner.de and
> Quoting Alan Braggins <ar...@chiark.greenend.org.uk>:
>>The idea of combining a Rohloff and Schlumpf has come up before in this
>>group, but I don't think I've seen it actually being done. Nor did I realise
>>previously that you could combine a Schlumpf with a tandem timing chain,
>>though the Schlumpf FAQ does mention it as possible.
>
> It does seem a bit like overkill. I mean, I know as well as anyone you
> want a very wide gear range on a tandem, but the tandem-and-Rohloff owners
> I know seem to find it satisfactory.
taking the "sail down the other side at 50 mph" in the eBay listing
as meaning 50mph without spinning out pedalling, then a Schlumpf Speed Drive
looks not completely pointless, if an expensive way to get four extra gears.
http://ritzelrechner.de/?GR=RLSH&KB=40,65&RZ=16&UF=2185&TF=90&SL=2.6&UN=MPH&DV=teeth
(16/40 taken from "Riders over 100kg/tandem" on
https://www.rohloff.de/en/experience/technology-in-detail/specifications/)
Lower solo ratio and High Speed Drive takes you from 4mph to 54mph at the
same cadence:
http://ritzelrechner.de/?GR=RLSH&KB=40,65&RZ=16&UF=2185&TF=90&SL=2.6&UN=MPH&DV=teeth
Or you can get the same range with a Mountain Drive and a 70 tooth chainring.
Or, as elsewhere in the thread, a more usual chainring and being careful not
to overload the hub to go lower.
asr...@yahoo.co.uk
Nov 26, 2019, 10:49:04 PM11/26/19
to
asr...@yahoo.co.uk
Nov 26, 2019, 10:49:14 PM11/26/19
to
On Thursday, March 21, 2019 at 12:34:57 AM UTC, Ian Jackson wrote:
> Incidentally, the lift part of a squat is presumably completed in much
> less than a second.
No it isn't, particularly for a world record attempt. We are talking about weights that are very close to the theoretical upper limit for a human being to lift (steroids or not).
> Incidentally, the lift part of a squat is presumably completed in much
> less than a second.
https://www.youtube.com/watch?v=IBbRmuPTHNQ
That is a bit more than one second.
Nick Maclaren
Nov 27, 2019, 5:42:09 AM11/27/19
to
In article <954dc92a-70f1-439f...@googlegroups.com>,
torque and RPM much both be measured at the pedals or both at the drive
wheel. Changing down gives you more torque, but no more power.
Regards,
Nick Maclaren.
<asr...@yahoo.co.uk> wrote:
>> >>>
>> >>>On the other hand... My left knee is now saying (quite reasonably)
>> >>>"You remember when you smashed me into the tarmac at 60kmh? I do...."
>> >>>and spinning shuts it up. So up hills I do a lot less low speed
>> >>>pushing even on the trike where balance is not an issue.
>> >>
>> >> I don't understand. If you spin faster in your bottom gear, you
>> >> necessarily travel faster, and necessarily use more power. Where
>> >> does it come from? I use the low range more-or-less only for hills
>> >> that I can't physically pedal up without.
>> >
>> >I'm not using an MD. I"m not even using the small ring on my triple
>> >most of the time on the 2 wheeler. The trike has a motor which has a
>> >torque sensor that prefers a cadence of 80 or so anyway.
>>
>> Ah! That makes a big difference. Even if you are my sort of power,
>> your total power (including motor) will be at least 350 watts, quite
>> probably significantly more.
>>
>> It is ridiculous that motors are optimised for high cadences, as very,
>> very few people who need (or, probably, use them) every ride higher
>> than 60 RPM and quite a lot stay below 50 RPM. For damn good reasons,
>> too, but I have posted that before :-(
>>
>> >Dunno about more power, it certainly means I puff more.
>>
>> You are generating more power! You can get a pretty accurate estimate
>> of your power from hill climbing, at least with a hill steep enough
>> to slow you right down.
>
>> >>>
>> >>>On the other hand... My left knee is now saying (quite reasonably)
>> >>>"You remember when you smashed me into the tarmac at 60kmh? I do...."
>> >>>and spinning shuts it up. So up hills I do a lot less low speed
>> >>>pushing even on the trike where balance is not an issue.
>> >>
>> >> I don't understand. If you spin faster in your bottom gear, you
>> >> necessarily travel faster, and necessarily use more power. Where
>> >> does it come from? I use the low range more-or-less only for hills
>> >> that I can't physically pedal up without.
>> >
>> >I'm not using an MD. I"m not even using the small ring on my triple
>> >most of the time on the 2 wheeler. The trike has a motor which has a
>> >torque sensor that prefers a cadence of 80 or so anyway.
>>
>> Ah! That makes a big difference. Even if you are my sort of power,
>> your total power (including motor) will be at least 350 watts, quite
>> probably significantly more.
>>
>> It is ridiculous that motors are optimised for high cadences, as very,
>> very few people who need (or, probably, use them) every ride higher
>> than 60 RPM and quite a lot stay below 50 RPM. For damn good reasons,
>> too, but I have posted that before :-(
>>
>> >Dunno about more power, it certainly means I puff more.
>>
>> You are generating more power! You can get a pretty accurate estimate
>> of your power from hill climbing, at least with a hill steep enough
>> to slow you right down.
>
>You have to allow for the fact that the power directed to the drive
>wheel is dependant on the gearing (lower = increased torque to the drive
>wheel).
In general, no, you don't. While power is torque x RPM x 2pi, the
>wheel is dependant on the gearing (lower = increased torque to the drive
>wheel).
torque and RPM much both be measured at the pedals or both at the drive
wheel. Changing down gives you more torque, but no more power.
Regards,
Nick Maclaren.
TMS320
Nov 28, 2019, 6:01:00 AM11/28/19
to
> Changing down gives you more torque, but no more power.
driven so tractive force (*) is probably more useful than torque.
Although it is possible to pretend that the crank drove a shaft into a
gearbox and gearbox output turned the wheel hub.
For any given power applied through the pedals, the TF developed on the
wheel is dependant only on wheel rpm, irrespective of gear. Changing
down reduces the force the feet apply on the pedals.
(*) TF ~= power/road speed
or TF ~= power/(pedal rpm x pedal development)
or TF ~= power/(wheel rpm x wheel size)
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