Ultegra/105 compatibility

Discuss light weight issues concerning road bikes & parts.
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DMF
Posts: 1062
Joined: Sat Dec 06, 2008 10:14 am
Location: Sweden

by DMF

Actually with careful setup (cable tension, derailleur alignment, limit screws) you can get the 7900 FD/5700 shifters combo to shift without the trim function on the big ring (done properly, the shifter won't even engage the outer trim position) and also use the whole cassette with only the inner trim position on the small ring. That way you will actually never use any trim and can use the full cassette without rub on both front rings.

Ofcourse you will still have to shift by/pass the small ring outer trim position when going from small to big ring, but I would say you barely notice that anyway. I've done this on both a Sram Red and Shimano Tiagra 4500 crankset with several different types of chainrings.

by Weenie


kulivontot
Posts: 1170
Joined: Sun May 16, 2010 7:28 pm

by kulivontot

sanddancer wrote:7900 and 5700/6700 are NOT. At least not fully. Front mech pull ratio is way off and (IIRC) using 7900 shifters with a 5700 mech means you need to put a stupid amount of force through the lever to get it to shift.

I got 7900 FD with 6700 shifters... Is that why I'm always rubbing 1-2 gears when cross-chained? I "upgraded" to 7900 and moved the 6700 FD to my TT bike..

davidalone wrote:( you CAN however, run a sram shifter with a shimano front derailleur or a shimano shifter with a sram front derailleur.)
brakes between sram and shimano are cross compatible as well.

I assume this DOES NOT apply for SRAM Red 10s with the new Yaw FD? I think I'm going to change out the whole shifting system to SRAM soon, the rear shifting doesn't feel crisp at all. The lever action just feels loose and plasticky.

davidalone
Posts: 589
Joined: Fri Feb 10, 2012 4:27 pm

by davidalone

I've not used a yaw FD ( and to be honest, I wouldn't. ) so I can't comment. but Velonews have tried it out here:

http://velonews.competitor.com/2012/03/ ... ity_209270

and if yaw works with older shifters I don't see why i wouldnt work with shimano shifters. not perfectly, but there you go.

my experience with sram is that you either like it or hate it. the 'plasticky' shifting is something I actualy like- it's solid and instantaneous, sort of like a manual gearbox on a racing car. it feels solid and you KNOW you've shifted. shimano shifts nice, but it's sometimes a little too smooth.

that being said I hate sram for other reasons, so I'm going back to shimano on the next change.

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