I'm building up a drop bar bike and working with sram for the first time.

The issue I've run into is that a local shop advised me that the indexing for the sram 11 speed road line and the mtb line was the same. So I've got a complete gx drivetrain (cassette, rear mech, crankset) hooked up to a sram s-500 bar-end shifter (which I have now been told is incompatible).

It should also be noted that I have trp hylex brakes so brifters aren't the ideal solution in this case.

I'm trying to salvage this build and it's been suggested that I just buy an apex rear derailleur and swap it out, but I'm concerned about it's compatibility with the 10-42t cassette (SRAM XG-1150 GX 11 SPEED).

If I could go back and do it again I'd just buy the complete road group with brifters and use mechanical brakes, but I'd like to avoid re-selling what I've got if possible.

  • 2
    Batman's suggestion below of just getting a Jtek unit is the good approach here. There are also derailer extenders such as Wolf Tooth roadlink, but 42 is out of its capability. Commented May 26, 2017 at 18:40
  • If the shop told you it would be compatible and you bought it from them, they should at least take the incompatible bits back.
    – Batman
    Commented May 26, 2017 at 20:33

1 Answer 1


I think you have two options:

  1. According to Zinn, you can use an Exact Actuation (not X-actuation) Rear Derailleur with the shifter, but I don't think there are any that take such a big cassette. So, you'd probably have to get a new cassette too.

  2. Use a JTEK Shiftmate 9. A Shiftmate is basically a pulley that you shove into the derailleur or shifter which adjusts the cable pull between two systems. The Shiftmate 9 takes a SRAM 11 speed road shifter and a SRAM 11 speed mountain derailleur and a Shimano/SRAM/Campagnolo cassette and makes them work together when you hook up the Shiftmate into the derailleur. Note that this is likely going to be a special order item made by a small company in the UK, and not cheap (looks to be ~41 USD on SJS Cycles; there are other retailers world wide, though).

  • Thanks @Batman! Do you have any experience using the Shiftmate. I've heard both positive and negative reviews.
    – Evan
    Commented May 26, 2017 at 20:54
  • 1
    Not particularly. Its pretty much your only choice afaik if you want to keep your components (as Nathan Knutson pointed out in the comments, there isn't a derailleur extender on the market that fits this cassette size). I think a lot of the bad reviews are probably due to in a large part mis-installation (which also happens with travel agents and stuff), though. It's a simple enough mechanism. Note that both travel agents and shiftmates are niche devices -- the user base is really quite small, and while some people spec'd their bikes knowing they'd need them, a decent amount probably didn't.
    – Batman
    Commented May 27, 2017 at 2:02
  • 1
    Late, late addition. Been using the shiftmate solution for about and year and it's working well. Thanks @Batman!
    – Evan
    Commented Apr 3, 2019 at 17:18
  • Thanks for the update, @Evan! Always good to hear things work.
    – Batman
    Commented Apr 5, 2019 at 0:04

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.