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on my new surly cross check i have installed the following:

  • 10 gear Dura Ace Barendshifters (7900),
  • 26-36-48 crankset,
  • xt front derailleur,
  • 10 gear xt shadow rear derailleur
  • 11-32 casette.

while shifting the front derailleur works fine, the rear derailleur does not shift all 10 gears. i have read about the incompatibility issues of road and mtb components and have come across the following hack:

This is a pretty popular hack. If you’re using 10-speed triple road shifters (Tiagra, 105, Ultegra), you can hook them up to a 9-speed MTB derailluer, a 10-speed MTB cassette and a 10-speed chain. As the 9-speed MTB derailleur pulls in the same way as a 10-speed road, you are essentially just increasing the derailleur cage length to increase the overall capacity. Keep in mind the 10-speed shifters will ONLY work with 10-speed road triple front derailleurs. Crankset: 50-39-30t Cassette: 11-36t Setup Capacity: 45t Smallest Gear w/ 700×38 Tyres: 23 Gear Inches

thankyou cyclingabout.com

would this work with my setup (when i exchange the rear derailleur)? the dura ace shifters are not mentioned and i have different crankset and cassette setup.

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  • Have you loosened both limit screws on the RD all the way? Which extent cannot be reached--the largest sprocket or the smallest? Or can you reach all of them if you adjust cable tension, but not all of them at a single tension setting? Which exact RD model?
    – John Zwinck
    Commented Feb 20, 2017 at 13:44
  • --> have not yet tried to loosen both limit screws, will do that later --> it does not got to the largest, neither does it go back down to the smallest. somewhere in between, the derailleur does not manage to move the chain (this remained unchanged when increasing cable tension) --> model is t8000 shadow, same as the crankset
    – Johanemus
    Commented Feb 20, 2017 at 14:05
  • edit: tried to loosen the limit screws a bit during installing, did not work
    – Johanemus
    Commented Feb 20, 2017 at 14:12
  • If you want to use bar end shifters you will need to use 9 spd durace as these have a friction mode.
    – Rider_X
    Commented Mar 16, 2017 at 1:19

2 Answers 2

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Your bar-end 10s-shifters must have the same index (cable-pull ratio per shift) as the normal STI 10s-levers: 2.3mm. That leads to the incompatibility with the MTB 10s-derailleur, which is build for the 3.4mm cable pull of Shimanos 10s MTB shifters. Using a 9s-derailleur, which requires 2.5mm cable-pull, brings you close to the index of your 10s-shifters, so that kinda works. Adjust it to align perfectly with the middle gear and the outer ones wont't be too far off. (ref: artscyclery)

If you want to use your 10s-MTB-derailleur (probably for the shadow+ capability?) with your 10s-RR-shifter, you'll need to change the derailleurs cable-pull ratio. You can do that either by re-routing the cable through a small hole in the derailleurs lever (ref: mtb-news.de and in english pinkbike). Or by using a special excenter-pulley (ref: Jtek ShiftMate) which translates the cable pull-ratio to the needed 2.3mm.

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  • You can also use 9spd durace bar end shifters in friction mode. 10 spd durace bar end shifters do not have a friction mode.
    – Rider_X
    Commented Mar 16, 2017 at 1:18
  • The older ones did? They had a clip on top you could flip over to put into friction mode.
    – Deleted User
    Commented Mar 16, 2017 at 13:52
  • @SuspendedUser last time I was building a commute bike this issue came up and I saw repeated mentions that the rear 7900 bar end shifter (10 speed) was index only. I ended up buying the 7800 9 speed which had an index or friction mode. Front shifter of both versions are friction mode only.
    – Rider_X
    Commented Mar 16, 2017 at 23:49
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Yes, putting a nine speed derailer and 10 speed cassette on will work because the actuation ratio matches.

You could also use a Jtek.

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  • Excuse me asking ... but why did you offer a less complete version of the answer I allready gave?
    – Marlon
    Commented Mar 20, 2017 at 11:37
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    @Marlon They're not the same answer because you state that the match "kinda works" due to a slight mismatch in cable pull. The cable pull per click isn't what's important though. The actuation ratio is what's important, and here they match perfectly. The 9s mountain RD in question has the same 1.7 ratio as a derailer that the 10s road bar-ends are intended to pair with. There's no error that has to be averaged out by setting it up to index in the middle etc.
    – Nathan Knutson
    Commented Mar 20, 2017 at 14:57
  • That doesn't coincide with my experience. When I set this combination up I had to adjust to the center gear. When I adjusted the setup from the first gear (like usual) the last gears did not catch on properly. They only shifted when I over-pushed the lever, and were audibly misaligned.
    – Marlon
    Commented Mar 21, 2017 at 9:19
  • And one more thing: You stated that the cable pull wouldn't be important, but the ratio would be - but that is not correct. The ratio describes the distance the derailleur is moved per distance the cable is pulled. But that is not whats important when it comes to the compatibility of the components - the amount of cable-pull itself is. By actuating the cable you basicly transmit information to the derailleur. If that information is off (too much / too little cable-pull) - the derailleur will be too. It's jus a question of how much.
    – Marlon
    Commented Mar 21, 2017 at 9:48
  • It would be off if you were using something other than a 10-speed Shimano cassette, but if I understand the question correctly that's not the case here. There's nothing different between a 9-speed era mtn rd and a 10-speed era road one with the same actuation ratio that will make them wind up in different places with a given shifter and cassette. They're not somehow dependent on getting a certain amount of cable pull. (There is a separate conversation about precision/slop in the pivots/etc, which needs to be tighter for 10, but the nicer 9s mtn RDs are fine in that regard.)
    – Nathan Knutson
    Commented Mar 21, 2017 at 15:56

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