Nexus chainset - what width chain?
Keiron
I'm going to use a nexus chainset for a SS mtb conversion but confused as
to what chain width is required. Much of the literature, including
Sheldon's pages, seem to say it will work with 1/8" or 3/32". Is this
right or am I misinterpreting? If this is so then I'm left wondering
which is best? I'd like 1/8" for strength but to my mind the solitary
chainwheel looks very thin and the chain staying on whilst off road is an
issue. So will 1/8" 'slide' about in comparison to a 3/32"?
(incidentally, no choice of rear sprocket yet so not a factor. I'll base
that on chain choice and not vice versa)
Advice from those with practical experience most valued!
Thanks
Keiron
RE 3/32" chains. I have the worry that the multispeed versions will be
poor for single speed given the extra lateral movement between the plates
but I'm assured this is not really a factor with modern chains. Opinions
on this please: are multispeed chains more likely to derail (given their
design)? Of course there is always the singlespeed 3/32"
Peter Cole
I don't see any reason to go to 1/8". I use a 3/16", and have for a
decade or so, on my fixed gear (Sheldon originally built it for me). I'm
6'10", 235 lb, and I don't worry about chain failure, that's more of a
concern with longer cranks and smaller chain wheels on my MTB's, which
have never broken a chain since I switched from Shimano to Sachs 10+
years ago (I had only one failure). FWIW, I use a DA track sprocket in
the back (my only DA), and a Shimano SS sprocket on the flop side (which
I never use). I don't even bother with 1-speed chains, I use the same
8-speed chains on all the 15 or so family bikes. Life is complicated
enough without creating more permutations.
Sergio Moretti
>
> - Show quoted text -
I've run a 3/32" chain with a fixed gear and never had a problem --
but there was no spring-loaded tensioner...
You can run a 1/8" chain on 3/32" chainrings/cogs (not vice-a-versa).
Given a choice, I'd go with a 1/8" chain AND sprockets for a single-
speed set-up -- should be more durable.
- Sergio Moretti
Peter Cole
And heavier. I don't know what motivates SS riders (or just this
particular one), but one of the premises of the whole FG thing was to
get a really light bike cheaply, almost entirely by removing stuff you
didn't need. I did leave one brake -- a very light one. I don't get the
hipster FG's with all that chunky 1/8" stuff. I guess fashion has its
price (and inconsistencies).
thirty-six
If you want to run the chain quite loose then it is best to get a
single speed chain, if they are available in 3/32" and you are
probably going to use a current 3/32 chainwheel then go with that with
the appropriate rear sprocket. Dont be afraid to change your mind .
If you are going to run the chain tight (poor choice in my opinion)
then a derailleur chain will do. But this wont even give you the
option to try to use a loosish fitting chain. If it looks like you
will not be using anty current road rings, remember that the fixed
setup might get you getting a selection, the selection you can draw on
for a traditional road setup. So again that points to 3/32" If you
start to unexplainedly break chains, then you will want to use 1/8"
if you dont mind splashing out anyway, go with this. You could
possibly grind the teeth slimmer to use with a 3/32" chain later.
Andre Jute
I have two bikes with full Nexus gruppo, including Nexus singlespeed
cranksets. The Nexus cranksets are nicely styled but I was less than
impressed when the teeth were very worn after only 2600km and 3200km
respectively. And that's inside fully enclosed chaincases, not on an
offroad bike with an open drivetrain. You might find the low-price
Nexus an expensive buy over the medium and longer term. By comparison
a steeltooth Amar singlespeed crankset for about the same price as the
Nexus delivered at my door, also in a chaincase, shows near-zero sign
of wear after 3400km; I think it might make two or three times that,
the sort of mileages that people brag about who have TA and other good
chainrings. I recommend the Amar (and Pieper workalike) cranksets,
though you have to go to German Ebay to get them.
It may be that the Alfine version, several multiples of the price of
the original Nexus cranksets, is made of better materials but the
choice of sizes is limited.
Stronglight for about the same price as the Alfine (i.e. pretty pricey
for a single speed) offers a single speed crankset with either one or
two bash guards, probably made for them by Sugino. Dot Bike has them
and Spa Cycles, the latter with better prices, or from Derek's Cycles
on ebay. I mention it because the Stronglight looks better than the
Alfine crank.
***
Turning to the chain, what's the point of building a singlespeed,
which is a light paradigm (except when it is a hub gear paradigm for
people like me), if you then add heavy stuff like 1/8in sprockets and
chains?
Even aside from that, one of the best known-durable chains, KMC's X8,
is 3/32in and widely used for round the world loaded touring on
Rohloff-equipped bikes. This is not a singlespeed chain but it is
pretty stiff laterally. I have an X8 on a singlespeed (Rohloff) bike
with 3400km on it, and there is zero elongation, whereas my other
bikes are on their second or third chain already at lower mileages,
though of course SRAM PCxxx etc are less expensive than the X8. KMC's
X8 in my opinion leaves any Shimano chain for dead. The only other
chain worth considering is Wippermann's Connex 808 in the same breath,
which also has special construction and nickel plating, but is a tiny
spot more expensive than the X8.
Notice that I don't even consider single-speed chains, for the simple
reason that they aren't as good at singlespeeding as the X8. And I
don't consider 1/8in chains because they are unnecessary. (In fact,
Herr Rohloff, who specifically designed his gearbox for rough MTB
work, considers 1/8in chains so unnecessary he didn't even leave
clearance for them -- and he first made his name as a chain
manufacturer!)
***
You asked for personal experience but I should also mention that the
cheaper weather-protected KMCs than the X8, though I don't have
personal experience of them, are well reputed for their longevity,
which might be worth knowing if you're building on a budget. KMC has a
decision tree on their site for choosing among their chains that I
found useful.
Andre Jute
"Cycling wisdom" is an oxymoron
AMuzi
In theory, well, people speculate on all sorts of things.
In practice 1/8" chain is cheap and durable, under $10 in
some pretty snazzy colors. Use that.
--
Andrew Muzi
<www.yellowjersey.org/>
Open every day since 1 April, 1971
landotter
Yup. Used three KMCs in "grey" this evening to finish off a Schwinn
tandem. Easy as piss to lengthen in case you take off a bit too much
and strong.
AMuzi
With a choice of nickel, gold, purple, pink, blue, red,
yellow, green and white you chose grey??
One of our wheel builders saved up chain scrap for a week
and made a mufti chain for her own bike.
landotter
> landotter wrote:
> > On Aug 4, 7:55 pm, AMuzi <a...@yellowjersey.org> wrote:
> >> Keiron wrote:
> >>> I'm going to use a nexus chainset for a SS mtb conversion but confused as
> >>> to what chain width is required. Much of the literature, including
> >>> Sheldon's pages, seem to say it will work with 1/8" or 3/32". Is this
> >>> right or am I misinterpreting? If this is so then I'm left wondering
> >>> which is best? I'd like 1/8" for strength but to my mind the solitary
> >>> chainwheel looks very thin and the chain staying on whilst off road is an
> >>> issue. So will 1/8" 'slide' about in comparison to a 3/32"?
> >>> (incidentally, no choice of rear sprocket yet so not a factor. I'll base
> >>> that on chain choice and not vice versa)
> >>> Advice from those with practical experience most valued!
> >> In theory, well, people speculate on all sorts of things.
>
> >> In practice 1/8" chain is cheap and durable, under $10 in
> >> some pretty snazzy colors. Use that.
>
> > Yup. Used three KMCs in "grey" this evening to finish off a Schwinn
> > tandem. Easy as piss to lengthen in case you take off a bit too much
> > and strong.
>
> With a choice of nickel, gold, purple, pink, blue, red,
> yellow, green and white you chose grey??
>
way.
Keiron
Cheapness is the secondary motivation here, behind wanting a training
bike. This is in my view is another good reason for 1/8" due to the
abundance of inexpensive and hefty bmx chains. I'm far too tight for posh
track stuff. But the primary factor in it's design is my weight: @240lbs
bikes, chains handlebars and all manner of components all like to flex
and twist under my mass, whilst I crunch down on the pedals. First and
last time, but clearly not the last, I rode a SS the chain slipped going
uphill (concrete bridge in fact) and 240lbs of weight hit the floor,
contact point: my lips. Lucky escape for my teeth. It was a flimsy set-up
from my old parts which is why I'm prepared to invest just a little to
ensure this doesn't happen again.
Keiron
Is there a choice between running a loose or tight chain? Advantages/
disadvantages? I thought the chain needed to just be the right/correct
tension?
Keiron
Agreed on all matters of cost and longevity. This exercise is largely a
matter of left over components to which I just recently included a frame
after it's current drive systems failed. I don't expect much distance out
of the Nexus, even on sight I'm not greatly impressed, although willing
to be surprised. Once it's worn out I'll probably have had my fill and
just donate the frame to the next SS adventurer.
Thanks AJ, I will read further in to the X8. Touring grade kit always
appeals, whether or not it should, but it sounds like a option to
consider.
Keiron
Ah, particularly interesting given similar weights (although your BMI is
much better!! grrr!). Don't you generally find bike equipment contrary?
If not all I can suggest that my aggressive off road method i.e. very
little skill and as much speed as possible, is the factor influencing my
bad luck with component failure. As above, this is why i'm 1/8" is of
interest, if it is in fact more "stable". On the road I'm happily use one
of a small cache of 5/6/7 speed chains (which seem to work with my 8s
too), each costing £3 a time. No issues at all.
Keiron
Thank you both. Just by way of rounding up and squaring off: you still
recommend the 1/8" with the Nexus? (Again, given that, to my eyes at
least, it looks narrow).
Norman
1/8" isn't stronger by virtue of being 1/8", since that
is merely the nominal distance between the inner
side-plates. For practical purposes I use 1/8" chains
on my fixed gear bicycles because I have a mixture
of sprockets on my rear wheels. Also setting the
pins on 1/8" chains is slightly easier. Also full-
bushing chains are virtually nonexistent in 3/32"
and I get close to twice as many miles compared
to bushingless.
As to your "slide" problem, that sounds like a
conceit with no real-world analogue. If your chain
is set with no more than 1/2" deflection at the
center of the longest span you should have no
trouble.
If you want maximum lifespan, get a steel
chainwheel and a >19zh rear sprocket.
Peter Cole
I hear your concern about slip/skip. I once went OTB like that when my
MTB chain skipped as I was pedaling standing (fortunately slowly). With
a FG, you can't use a chain tensioner, and the lack of a freewheel makes
dropping a chain a more potentially dangerous thing, so I pay careful
attention to chain slack, before and during rides.
Track sprockets have nice tall teeth, but bouncing chains can come off
anyway. I think they're worth the extra $$. I know your application is
SS, not exactly my area of experience, but I'd say that 3/16" components
are strong enough, so go either way depending on what your component
preferences are.
landotter
I've run every sort of bmx and gear chain with a Nexus hub. It does
not matter a whit. Get the one that looks coolest.
AMuzi
A touch too loose may be unaesthetic but works fine.
Just a bit tight wrecks bearings in hub and crank, eats
chainring teeth, runs loud and rough. Avoid that.
Ensure there's 10~12mm movement at the tightest spot:
http://www.yellowjersey.org/chainchk.html
If you're uncertain, go loose.
landotter
X2
I see too many folks making weird excuses for running stupid tight
chains. The worst being "I'm running a single speed cassette cog",
with the answer being--Shimano DX cogs are around seven bucks, how
much does replacing your wheelset cost?
thirty-six
If the chain is loose in all crank/wheel positions, it will correctly
lubricate. When it is tight as it leaves the front there is no space
for the lubricant to go and will show unecessary drag and wear. If
you are using a 16t sprocket or larger there should be no temptation
to go the tight route, apparently some think the chain somehow will
jump off the sprocket. A tight chain set up to me is the recommended
of finding the 'tightest' crank/wheel positions and then allowing for
1/4" up and down. (1/2" overall). You can have it quite slack so long
as it doesn't foul the tyre. The stiffer single speed chains can
handle this better. Using a loose chain (dangling) means you get
feedback to your efficiency of pedalling, it chatters when you have
speed variation in your pedal cycle. Tightening the chain stops this,
so does learning to turn the cranks with constant torque. So you can
either wear a chain out (and possibly other damage) in six weeks or
learn to pedal smoothly in that time and still have a perfect
drivtrain. Cheap motor oil is sufficient, unless you prefer the smell
of something else.