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For over a year now I'm using Sram's 1x11 X01 drivetrain. It works great, but the only thing I miss from my 3x9 XTR is the double up-shift on the rear derailleur. With 11 gears it only makes even more sense -- it's often annoying to click the trigger 4 times when starting a downhill section.

I know on the 3x9 XT trigger it was easy to do, as it was almost the same as XTR, but Sram's shifters probably work completely different... Is it possible to "hack" the X01 trigger shifter so it can double up-shift like the XTR?

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From what I remember (it's been a while since I've torn one apart), the "up" shifts on SRAM shifters are a mostly passive affair. You click the trigger, and this essentially gets a pawl out of the way of a spool inside the shifter which holds the cable. This spool unwinds one "shift" worth of cable due to the spring tension on the rear derailleur pulling on the cable. The rotation of the spool is stopped by a sear of some sort which catches the spool when the trigger is depressed, and resets when the trigger is released.

The only "hack" I could imagine is to remove or modify that sear, but more likely than not, what would happen is you'd down shift as normal, but pressing the up shift trigger would immediately release all of the remaining cable, shifting you from wherever you are down to the smallest cog. Which sounds completely miserable to me.

  • There is also a spiral spring inside the shifter, relying only on the derailleur spring tension probably wouldn't be as reliable. But, as you said, the release mechanism is constructed in a way that multi-release (how I learned it's called for Shimano shifters) is probably not possible. – quezak Jun 7 '17 at 13:19
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[conclusions from my own research]

I opened the upper shifter cover to study the release mechanism. It looks like it's fundamentally different than in Shimano shifters, and implementing a multi-release action may be impossible.

In Shimano the release lever is pushed forward (rotated around the shifter center), and then it releases one click on the shifter index. When pushed further it just releases another click. So "tuning" 9spd XT shifters to have this just required removing a small piece that was blocking the lever after first click.

In SRAM shifters, however, the release lever doesn't move forward, but turns upwards, using this movement to slide a metal plate inside to the left. This probably releases one tooth on the index cog below the cable spool, but then blocks the cog from turning further on the right side (as the metal plate is still pushed to the left). When you release the lever, the plate slides back right, the central cog rotates a millimeter more, and blocks the cog again on the left side, as before the shift.

I'll add more if I find out anything, cause I don't want to experiment on my only shifter :) To conclude, it's probably impossible:

  • the metal plate blocking the index cog has to move left and back right for a complete relase cycle
  • there is probably no room for the lever to turn upwards further than it does now
  • You can mark your own answers as correct. – RoboKaren Jun 8 '17 at 5:06

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