I recently converted to SRAM Rival 1x and don’t like Double Tap. Is it possible to add a left lever which shifts into smaller cogs while the right lever continues to shift into larger cogs (which I believe is how the eTap AXS version is setup)?
Assuming a cable would be added for the second lever, would the derailleur be able to accommodate two different cables for shifting?
No, for cable operation, Double Tap is Double Tap. You can’t convert it to something like Shimano or Campy 2-lever shifting function.
If you really want something different for shifting function, you kinda have to swap the whole system to a different brand.
Is it the Rival rear derailleur that can’t accommodate two different inputs for shifting? My SRAM mechanical MTB rear derailleur can, so made me wonder about the Rival one.
What? There is no standard rear derailleur I have seen that uses 2 cable inputs.
All regular derailleurs use a single cable to pull to larger cogs, and a spring returns to smaller ones.
Ah, ok, makes sense (as you can tell, I’m not super mechanically inclined). In that case, assuming my Rival derailleur works in the same way, what would prevent it from working like that with the addition of a left lever and cable?
I clearly don’t understand the details of how a derailleur works and why specifically it is not possible to convert from Double Tap to a two lever system and would appreciate if someone could kindly explain
Without driving into the details, you are essentially talking about a major modification to the shifter system. It was designed and built wiith one method of function in mind.
It would be too difficult and costly to try and turn it into something it’s not vs just biting the bullet and paying to swap to Shimano parts with the shifting you want.
Thanks, that’s helpful for overall derailleur function but not as much for the specifics of how the cable actuates a movement of the chain from cog to cog. Specifically understanding how a Double Tap lever does the latter would be key to knowing whether two levers could do the same thing for a Rival mech derailleur (as is the case for the a Rival eTap AXS derailleur and Eagle MTB derailleurs)
It seems you’re conflating some electronic shift possibilities with mechanical realities. Put simply, in mechanical shifting (Double Tap) one physical cable puts tension into the RD system, which the springs in the RD pull against to keep itself in position. The slack provided, or tension added to the single cable is what permits or causes the RD to move inward or outward.
There is no (practical) way to have a left lever cause the right lever to add tension or release tension on that single cable.
Electronic shifting (AXS, Di2) is a-whole-nuther ball of wax, which I have ZERO experience tinkering with.
1 Like
Ah, ok, thanks for the very helpful description (without any snark) that I didn’t appreciate from the video. And I now see how electronic and mech/cable would allow different possibilities.
1 Like
Linking for general interest only: it is indeed possible to design a derailleur where you have two input cables. One cable pulls to upshift it, the other pulls in the other direction to downshift it, no return spring.
I said possible, but I didn’t necessarily mean practical, and I certainly didn’t mean that it’s possible to redesign a stock SRAM, Shimano, or Campagnolo RD to work this way.
2 Likes
Yup, I have Rival AXS on my Tarmac. It’s really easy to shift when I’m down in the drops, e.g. racing a crit.
Not that much of an improvement if I’m on the hoods.
Yes, but AXS does not use cables. It’s all signal driven.
You cannot compare electronic to mechanical.
I know that.
Just trying to soften the blow of the “bad news” that what he was seeking to do isn’t possible.