Drivetrain Hack

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John McBurney

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Nov 8, 2019, 8:31:39 AM11/8/19
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I want to share my latest build with the group to show what I’ve done with the drivetrain. When I was thinking about this I read as much as I could in different forums, but at the end there was a certain amount of a leap of faith involved. I want to share with this group as others may have a similar inclination. 

First about the bike, it’s a custom Carver low trail rando Ti frame with a Soma low trail caliper brake fork recently acquired from list member Luke Heller.

Now about the drivetrain, in summary it’s a wide range 2x8 with Dura Ace 9 speed bar cons. The crankset is the heart of the system: Shimano CX 50. This is a great sifting crank, 46/36. The smallest ring it can take is 34 with the 110 mm bcd. The rear derailleur is a 9 speed Shimano XT long cage. 

I wanted to run a lower than 1:1 low final drive. I found the new wide range cassettes offered by manufacturers such as Sun Race, Box and Microshift really interesting. I chose an 8 speed Sun Race 11-40. It is an all steel unit. Nicer designs with alloy spiders start at 9 speed. I wanted 8 speed in order to have non fiddly friction shifting. I heard that wear may be an issue with the lower end 8 speed cassette and if that’s true I may try to convert to 9 speed indexing, although that may mean sourcing a long cage road derailleur. 

The RD will shift a 36 cog so in order to shit the 40 requires an extension link which lowers the top jockey wheel. Wolf Tooth makes these (Road Link and Goat Link) but so does Sunrace. I bought the Sunrace as it is cheaper and I was more confident it would work with the Sunrace cassette. The gear capacity of the RD is 41 teeth. With this setup the gear range is 39 so no problem. Cross chain 46-40 causes rub on the foo of the FD and of course should be avoided anyway. I haven’t found the lack of a clutch to be an issue, but I did source a Microshift Advent clutch long cage RD if I change my mind. The XT is much prettier IMO. 

The resultant gear range is below with a nice high of 113 and a low of 24 with nice steps in between. 

So far I’d say it works great! 8 speed is the sweet spot for friction. I’ve had no problem with ghost shifts under power. There is excellent tactile feedback when shifting. 

So in summary, this works extremely well. The parts are available an affordable. Highly recommended!



113.688.9
96.175.2
83.365.2
69.454.3
56.844.5
44.634.9
36.828.8
31.224.5

John McBurney

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Nov 8, 2019, 9:26:24 AM11/8/19
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I’m trying to repost. I got an error the first time. I realize this isn’t about a Rivendell but it’s really about the drivetrain and may be of interest to Rivendell owners inclined to think outside the box

John

Steve Palincsar

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Nov 8, 2019, 1:30:23 PM11/8/19
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Judging from the photo, you have a recent vintage 9-speed MTB rear derailleur.  If so, all you need to convert to 9 speed indexing is a 9 speed right hand shifter.  In Shimano world, 8 and 9 speed MTB rear derailleurs are compatible with road shifters 8-10 speed.  10 speed MTB rear derailleur changed the cable pull and needs a TanPan device to make the cable pull compatible.  And if you're running 8, no need to get into the additional complexities and nuances of 11.

On 11/8/19 9:26 AM, John McBurney wrote:
I wanted 8 speed in order to have non fiddly friction shifting. I heard that wear may be an issue with the lower end 8 speed cassette and if that’s true I may try to convert to 9 speed indexing, although that may mean sourcing a long cage road derailleur. 
-- 
Steve Palincsar
Alexandria, Virginia 
USA

Joe Bernard

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Nov 8, 2019, 2:07:09 PM11/8/19
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Correctamundo, I've used that derailer with those 9-speed bar-ends. Easy peasy if you switch to a Shimano/SRAM 9 cassette.

John McBurney

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Nov 8, 2019, 4:21:16 PM11/8/19
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Hi Joe,

Thanks for your observation. In the many generations of this bike I ran 105 9 speed brifters with this derailleur. It shifted “ok” but not great. I was told that with the Shadow XT mech that the road and mountain parted ways and weren’t compatible. Of course I’d also used those on my cross race bike and crashed in a sand pit filling the right side with sand. 😐

This will only be an issue if I can’t get 8 speed cassettes of good quality. 

I just did a 35 mile ride with 3000 feet climbing going over Paris mountain. At several points along the 2 mile 1000 ft climb the grade is well over 10% and at the finish it’s over 15%. Sitting and spinning at 80-90 rpm on those climbs is a revelation. 

But when we go up we must also go down. The 113 gear inch 46-11 is pretty fast and I rarely spun out descending. 

John 



On Fri, Nov 8, 2019 at 2:07 PM Joe Bernard <joer...@gmail.com> wrote:
Correctamundo, I've used that derailer with those 9-speed bar-ends. Easy peasy if you switch to a Shimano/SRAM 9 cassette.

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Steve Palincsar

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Nov 8, 2019, 4:51:10 PM11/8/19
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On 11/8/19 4:20 PM, John McBurney wrote:
> Hi Joe,
>
> Thanks for your observation. In the many generations of this bike I
> ran 105 9 speed brifters with this derailleur. It shifted “ok” but not
> great. I was told that with the Shadow XT mech that the road and
> mountain parted ways and weren’t compatible.


You were misinformed if the Shadow XT was a 9-speed.   Road and MTB
parted company with 10-speed MTB DynaSys.   In fact, the "standard
solution" to getting lower gearing with a > 32T large sprocket during
the entire 10 speed road era was 10 speed shifters, 9 speed MTB rear
derailleur.  Many of my riding companions have the same setup with 10
spd cassettes w/36T large sprockets.

John McBurney

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Nov 8, 2019, 5:16:13 PM11/8/19
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Good news!  

Anyone with an opinionated experience  about the 8 speed 11-40 cassettes? 

Are they durable?  

John 

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Joe Bernard

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Nov 8, 2019, 6:24:46 PM11/8/19
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Yes, a 105 brifter will shift a Shadow XT 9 "ok", but bar-ends are better at it. With brifters the shift either takes or it doesn't, there's not much you can do to help it along. Bar-ends are technically index (rear), but you still have the friction-like ability to coax onto a recalcitrant cog. Related: Me no likey brifters.

Steve Palincsar

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Nov 8, 2019, 6:30:23 PM11/8/19
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However, to be clear, that is true for all rear derailleurs, not just Shadow XT 9.  Basically, what you are saying is, bar-ends are better -- and I agree, as you can see here.

 

On 11/8/19 6:24 PM, Joe Bernard wrote:
Yes, a 105 brifter will shift a Shadow XT 9 "ok", but bar-ends are better at it. With brifters the shift either takes or it doesn't, there's not much you can do to help it along. Bar-ends are technically index (rear), but you still have the friction-like ability to coax onto a recalcitrant cog. Related: Me no likey brifters. 

Benz, Sunnyvale, CA

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Nov 8, 2019, 9:42:34 PM11/8/19
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On Friday, November 8, 2019 at 3:24:46 PM UTC-8, Joe Bernard wrote:
Yes, a 105 brifter will shift a Shadow XT 9 "ok", but bar-ends are better at it. With brifters the shift either takes or it doesn't, there's not much you can do to help it along. Bar-ends are technically index (rear), but you still have the friction-like ability to coax onto a recalcitrant cog. Related: Me no likey brifters.

Sounds like you may have a cable friction issue, or something else that's less than optimal. All well-adjusted Shimano STI, Campagnolo Ergopower or SRAM DoubleTap should shift plenty quick with little hesitation, and no coaxing.

Joe Bernard

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Nov 8, 2019, 10:09:31 PM11/8/19
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"Should with its dedicated road derailer" doesn't always mean "great with an mtb derailer."

John McBurney

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Nov 8, 2019, 10:27:16 PM11/8/19
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Well don’t forget I augered into a sand pit and literally filled the right brifter with sand. I think I did a really good job cleaning it out but you can only so so much. 

The DA bar cons are nice in friction. Gotta be careful standing though.  I was hoping to use my Riv down tube shifters ( like sun tour superbe pro but pull more cable) but the frame wasn’t set up for them. 

I hope my “addiction to friction” will be able to continue and make all this moot. 

John

On Fri, Nov 8, 2019 at 10:09 PM Joe Bernard <joer...@gmail.com> wrote:
"Should with its dedicated road derailer" doesn't always mean "great with an mtb derailer."

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Steve Palincsar

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Nov 9, 2019, 9:08:04 AM11/9/19
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On 11/8/19 10:26 PM, John McBurney wrote:
> Well don’t forget I augered into a sand pit and literally filled the
> right brifter with sand. I think I did a really good job cleaning it
> out but you can only so so much.


A few years ago, while JRA my bottom bracket spindle broke and I ended
up crashing in someone's yard.  I was lucky: I rolled, the bike tumbled
around a bit but wasn't damaged, and the worst thing that happened to me
was I tore my winter tights.  (And came to a halt after all this face
down, arms out, looking at a fresh steaming pile of dog do right in
front of my face.)

After the LBS replaced my bottom bracket and checked out the bike, I
went on a ride to the National Arboretum.  We climbed Hickey Hill and at
the Asian Collections parking I briefly applied by my brakes... and my
rear brake wouldn't release.  The lever was jammed.  ???   My friends
and I played with the cable and bit and eventually got the bike rideable.

After I got home I brought the bike to the LBS.   They found a small
round pebble inside the right brake lever that had gotten inside as the
bike was tumbling during the crash.  During the ride it had shifted so
that it jammed the lever.  No one in the shop had ever seen anything
like it.


>
> The DA bar cons are nice in friction. Gotta be careful standing
> though.  I was hoping to use my Riv down tube shifters ( like sun tour
> superbe pro but pull more cable) but the frame wasn’t set up for them.
>
> I hope my “addiction to friction” will be able to continue and make
> all this moot.


There are folks on the iBOB list who friction-shift Hyperglide 10 and
are happy.  I'm not one of them: my happiness with friction shifting
Hyperglide ends at 7.

Steve Palincsar

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Nov 9, 2019, 9:13:57 AM11/9/19
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Taking this as a blanket statement, I am going to disagree with you.  For compatible Shimano rear derailleurs (i.e., excluding oddball situations like 1st gen Dura Ace 8) there is no difference in index shifting performance per se between road rear derailleurs and MTB rear derailleurs.   Of course, wide range rear derailleurs don't shift as well on narrow range cassettes as rear derailleurs optimized for narrow range, but that has nothing to do with the shifter. 

On 11/8/19 10:09 PM, Joe Bernard wrote:
"Should with its dedicated road derailer" doesn't always mean "great with an mtb derailer." 

John McBurney

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Nov 9, 2019, 9:27:32 AM11/9/19
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What is the gear range on those long cage RD? There are a few on EBay but they look more like mid cage designs to me. 

John

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Joe Bernard

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Nov 9, 2019, 2:20:32 PM11/9/19
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My comments about how brifters work with mtb derailers was not a blanket statement. Sometimes they're perfect like when I used Ultegra 10 with a Shadow XT and 11-34 cassette.

Pancake

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Nov 10, 2019, 11:51:27 AM11/10/19
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What a great range with this setup! When my triple crankset is worn I'm hoping to replace it with a similar setup to yours (though in 2x9) with a Sugino or Silver double in front and probably with 34-46 because I'm a heavy fellow surrounded by mountains that need the easier gearing. I'll probably stick to a Shimano XT front deraileur too. But this was super helpful info, thanks a million!

Separately: what is that front rack? I'm looking for an odd size (about 8"x8" +/- 1") platform top for under $100 to fit a one-off ILE "demi" porteur bag and that looks like a good fit. The only good options I've found are:

VERY handsome ride, only downside seems to be it's so well appointed and suited that maybe you won't need another bike after that!

Abe

John McBurney

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Nov 10, 2019, 12:34:15 PM11/10/19
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Thank you!  The front rack is a custom that I bought with the frame. It’s as deep as Marks rack or similar but wider. It’s as wide as the Acorn rando box. It attaches to the fork by boxing out the brake. I decided to splurge on Paul Centerpull centermount brakes and the normal ways these would have been difficult at best. 

Honestly if I don’t get decent life out of this cassette I’ll go 9 speed 11-40 index in order to try to get better steel. BTW the FD is an Ultegra. 

I really like the narrow double as an alternative to a 1X or triple when combined with the wider range cassette. BTW if you go with the 34-46 and 11-40 you’ll be right at the gear capacity of the XT 9 speed speed Shadow RD (41 teeth) 

There are higher tooth capacity RD. For example the Microshift Advent will shift a 42 and has 47 tooth gear capacity. It also has a clutch. It is only supposed to work with their shifters so friction shifting solves that. 

John



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Joe Bernard

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Nov 10, 2019, 1:41:34 PM11/10/19
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Ooh, that's a thing I need to try. I just picked up a Clem H with the Microshift thumbies swapped so the front ratchety-friction works the rear derailer. I have an Advent group, I'm going to mount the cassette and derailer and I'll let y'all know how it goes.

John McBurney

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Nov 13, 2019, 5:33:11 AM11/13/19
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Hi Joe

Any follow up on this?

John

On Sun, Nov 10, 2019 at 1:41 PM Joe Bernard <joer...@gmail.com> wrote:
Ooh, that's a thing I need to try. I just picked up a Clem H with the Microshift thumbies swapped so the front ratchety-friction works the rear derailer. I have an Advent group, I'm going to mount the cassette and derailer and I'll let y'all know how it goes.

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Joe Bernard

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Nov 13, 2019, 10:16:21 AM11/13/19
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John, I haven't changed much on the bike yet so not much to report. Unfortunately for my hobby of taking bikes apart and putting them back together in a different way, Clems in stock form are hard to improve!

Fullylugged

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Nov 13, 2019, 12:51:03 PM11/13/19
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Nice looking bike John. I used that CX-50 to build a New Albion Starling for a relative and it is smooth unit, intended for cyclocross so very tough. I need a lower gear than you because I have weak old legs. I put a Salsa 26 in place of the stock Campy 30 on a triple and went with an 11-36 rear 9 speed on 105/Synergy wheels I built. 26/36 works for me when going up long grades that I otherwise would climb more quickly in a taller gear, and when I need to get up a real wall of a hill. The Clem I just assembled for a friend has a 46/34/24 with that same 11-36 rear. It works well too. I friction shift. I’ve avoided 40 in back because it starts to get kind of heavy. Even the 36 is noticeably heavier than the 34 or 32 that I run on other bikes.

Happy trails to you!

John McBurney

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Nov 13, 2019, 3:32:32 PM11/13/19
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Thanks Bruce! 

John

On Wed, Nov 13, 2019 at 12:51 PM Fullylugged <bruce.h...@gmail.com> wrote:
Nice looking bike John.  I used that CX-50 to build a New Albion Starling for a relative and it is smooth unit, intended for cyclocross so very tough. I need a lower gear than you because I have weak old legs.  I put a Salsa 26 in place of the stock Campy 30 on a triple and went with an 11-36 rear 9 speed on 105/Synergy wheels I built. 26/36 works for me when going up long grades that I otherwise would climb more quickly in a taller gear, and when I need to get up a real wall of a hill. The Clem I just assembled for a friend has a 46/34/24 with that same 11-36 rear. It works well too.  I friction shift.  I’ve avoided 40 in back because it starts to get kind of heavy.  Even the 36 is noticeably heavier than the 34 or 32 that I run on other bikes.   

Happy trails to you!

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Pancake

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Dec 10, 2019, 12:28:36 PM12/10/19
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Did you ever mount the Advent derailleur and try it with friction shifters? Curious 9 speed cassette users want to know how their thumbies might work with this affordable, clutched derailleur ...

Also, thanks for the VO rings!

Abe

Joe Bernard

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Dec 10, 2019, 12:58:26 PM12/10/19
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Sorry Abe, the stock drivetrain is too good to change on my mustard Clem H, plus I'm leaning towards selling that bike when the custom gets here so don't want to muck it up too much. The Advent stuff with indexed shifter may see duty on the custom.

Pancake

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Sep 22, 2021, 1:41:04 PM9/22/21
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Hey Joe, thanks for the great ride route last weekend. 
I ordered the Advient 9 long cage clutch derailer (to replace the SRAM GX 10 speed that gave me trouble last ride - bent and stripped b-limit screw lead to stripped threads in the derailer itself, fixed now [with new m4 bolt and some lock nuts] but still leaves much to be desired). 
I'll report back after installing and riding it for a while. If that doesn't work my next rear derailers to try will be:
Sunrace RD-M900 ($44 clutch 9 speed medium cage with 2x capacity up to 46t and 1x capacity up to 51t)
Box Components Three Prime 9 X-Wide ($75) or Two ($125) - also with clutch, similar or same capacity.

Forever trying to get the ideal rear derailer with friction shifter,
Abe
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