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Old 01-17-08, 11:37 PM   #1
mx_599
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SRAM road derailleurs used offroad...

have any of you tried to use SRAM road (rival/force) derailleurs off road?

the ratio pull isn't explicitly stated anywhere (that i quickly found...) and i suspect SRAM altered something so people wouldn't do this...?

however, have any of you tried to see if the ratio was close enough that it wouldn't matter?

i guess there might be a problem with clearance on the larger cassettes of mtb's...but maybe not...still offers some interesting possibilities

how about the front derailleur at least? seems more likely this would work....no? since lots of people use an xtr front, has anyone looked at the road fronts instead for there mtb?

why you ask? advantages? well, lighter and cheaper...by a lot.

thanks
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Old 01-20-08, 12:16 AM   #2
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Wouldn't there be problems with the front derailleur due to the road FD being designed for large chainring that's around 10 teeth larger than a normal MTB chainring?
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Old 01-20-08, 12:25 AM   #3
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Originally Posted by kramnnim View Post
Wouldn't there be problems with the front derailleur due to the road FD being designed for large chainring that's around 10 teeth larger than a normal MTB chainring?
this would most likely be the least of the the problems. it wouldn't amount to a huge diameter difference and i think the front dérailleur curvature would match fairly close.

i do think a front D is more hopeful than a rear though.

i posted this in the mechanics forum if anyone is interested.
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Old 01-20-08, 10:18 AM   #4
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I can't see them engineering an entirely different pull ratio just for road, I think its safe to assume its 1x1. Might be worth trying to be honest. shimano 105's are as popular up here as anything due to how short they are and how tense they hold the chain, is sram's works in a similar way, it could be a really good use.
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Old 01-20-08, 10:53 AM   #5
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I remember reading at sram website that x.0, x.9,... rear derailleurs won't work with road shifters. So it probably may not work the other way around. They call the road groups' actuation as "exact actuation", not 1:1, and if I'm not mistaken the mountain groups' 1:1 ratio is not exactly 1:1, it's 1:1.1, 1:1.2 or something like that in reality.
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Old 01-20-08, 10:57 AM   #6
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Derailleurs

As expected, SRAM has carried over some of the features of its MTB rear derailleurs to the road versions. The new derailleurs use what SRAM calls Exact Actuation cable pull ratio. This requires more cable movement than competing systems in order to actuate a shift, but not as much as on SRAM's mountain systems, resulting in a more robust setup that should be more tolerant of cable friction or slight misadjustment. While this bodes well for long-term and all-weather performance, it does, however, mean that SRAM's new rear derailleurs will not be compatible with either Shimano or Campagnolo levers. The top level Force rear changer will include a carbon fiber pulley cage and magnesium inner parallelogram plate that reduces the weight to only 174g. Rival will use a more conventional aluminum pulley cage and inner link but still will only tip the scales at just 190g. Both rear derailleurs will handle up to a 27-teeth rear cog.

SRAM has wisely designed the new Force and Rival front derailleurs to be fully compatible with either standard or compact chainrings, the latter of which is becoming increasingly common. A proprietary cable pull ratio is also used here as well (again, signaling a lack of compatibility with existing components) and both front derailleurs will be available in braze-on style with additional clamps required for band-type mounting. Both Force and Rival front derailleurs use a steel cage and aluminum construction for weights of 88g in braze-on version, and 102-103g for the clamp version.
Found a couple of articles that back up what erhan was saying. Seems to be true
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