SRAM/Shimano compatibility (road)
 

I read recently that the SRAM cassette spacing (for the new road groups) is the same as Shimano's, so you can swap cassettes or wheels w/ no worries. However, they said that the rest of the drivetrain was a "closed system", and thus had to be all SRAM. I'm just curious - why couldn't you use Shimano derailleurs w/ the SRAM shifters? What is it that makes them incompatible?

if the road group is anything like the mtb group, it uses a different cable pull ratio and as such the rear derailleur has to be mated to a SRAM shifter.

- Joel

I was under the impression that SRAM was touting "Shimano Compatibility" as a selling point.

Tim

No... One of SRAM's promotional videos actually mentions it's not compatible with Shimano. There are curious little pulley things you can get that compensate for the difference though - you can get them to use Campy too. Hunt around; I don't remember the website and I don't know how good they actually are.

The "little pulley things" are made by Jtek (www.jtekengineering.com) and are available to make various combinations of Campy and Shimano components work together. I don't know if they have them for Shimano/SRAM or Campy/SRAM yet.

As noted, the only Shimano compatibility that SRAM maintains is cassette spacing and spline pattern so you can use Shimano cassettes and/or hubs with SRAM components. You cannot mix-and-match Shimano and SRAM shifters and derailleurs.

Thanks for the info, everybody! I had been hoping to maybe just by SRAM brifters, and use my old Ultegra group for the rest of the setup, but I guess that's not an option. I may just stick w/ Shimano then, and just upgrade to 10spd. That way I can just by the brifters, cassette, and chain, and I'm all set. That's what I did w/ my other bike, and it worked great.

I think Sram make two kinds of MTB rear der's, and maybe shifters as well. One has the proprietary Sram cable pull ratio, the other is Sh-compatible. Dunno about the road stuff.

In the FAQ on SRAM's website, they have the following to say:

SRAM shifters pull the cable a certain amount for each click, and that amount is different from what Shimano shifters pull. Since the cassette spacing is the same as Shimano's, the derailleurs need to compensate for the different cable pull, so the derailleurs land in the right place. So you have to pair SRAM derailleurs with shifters. But you can use a SRAM cassette with Shimano shifters/derailleurs (and vice-versa I imagine).

I just had the SRAM force/rival installed on my Griffen Vulcan:

http://www.bikeforums.net/showthread.php?t=237694

U MUST use the Brifters with both Front and Rear Derailleurs. No Exceptions.

All else is compatible with Shimano.

KMC 10SL chain was my choice with the Dura Ace 10/27 cassette.

Couple that with the R700 and it shifts perfectly with no rubbing. As a matter of fact it's very quiet as if it was meant for each other.