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[Closed] Dire Shimano vs SRAM actuation ratio question

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[#321025]

Help! I'm in need of the combined 'Shimano meets SRAM' experiences of the STW massive.

I'm trying to get a X.7 SRAM front mech to play nicely with a ca. 2003 Shimano LX shifter. Extensive googling says that this should indeed be possible, as does the SRAM product documentation. Both manufacturers supposedly use a 1:1 actuation ratio for their front mechs and shifters.

So imagine my surprise when I fit the SRAM mech today and the chain now shifts from the smallest chain ring to the largest in a single shift, skipping the middle ring entirely. It seems that the shifters are working on a 2:1 ratio. Can this be right? I'd assume the the internet was just plain wrong, except that I have a set-up on my other bike with a SRAM Xgen front mech cooperating with a Shimano XT shifter.

Much jaw-droppage in the shed this afternoon. Has anybody hit this one before?


 
Posted : 19/02/2009 7:54 pm
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Never had a problem like that before. The only thing I can think of is perhaps the 'hook' for the middle gear is worn and you are changing all the way without knowing it? The shifter is quite old.


 
Posted : 19/02/2009 9:39 pm
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Nothing odd like a bottom pull mech set up as top pull (can't see why this would be possible/possible etc - just a thought).
Mech not set 'square' to the chainline (i.e. needs to swivel around seat tube)?


 
Posted : 19/02/2009 9:47 pm
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Thanks for your comments - it does sound like I've done something wrong. I will persevere with it a bit longer. At least it is supposed to work then!


 
Posted : 20/02/2009 9:39 pm