Bicycle Mechanics - Mix & Match Drivetrain Problem

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giantxc
05-10-08, 09:48 PM
Help!! :cry::cry:
I'm presently building up my girlfriend's Ritchey Breakaway and am having a seemingly unsolvable drivetrain compatibility issue. I'm trying to run the following:
Sram Rival compact crankset
Dura ace 9spd front brifter (dual)
105 rear 9spd brifter (the rear dura ace she bought at a swap meet is shot)
FSA Compact front derailleur
Ultegra 10spd, Long Cage rear derailleur
SRAM 9 spd cassette (12-26)
SRAM 9 spd chain
Here's the problems:
Front: The chain rubs on the outer cage of the front derailleur in all cogs despite being adjusted as far out as possible. Cable tension is fine. The inside adjustment as as far out as it can go without rubbing in the small ring.
Rear: In nearly every cog and both chainrings the chain rubs on the outside of the derailleur cage near the lower pulley (closest to the ground).
A plausible cause for both problems would seem to be a dramatic chain line problem caused by a crankset with too much spacing but I can't see how this can be with a standard Rival crankset.
The only other thing I can think of is the two problems are unique and the front is caused by a worn out front brifter and the rear is a 10spd/9spd compatibility issue.
Thoughts?
greyghost_6
05-10-08, 10:47 PM
Thats a lot of stuff going on. First I would toss the idea that the "brifter" you speak of is worn. Yes the chain line may be off since some bottom bracket/cranks are good on some frames depending on how far out they go. Some older and newer frames don't "like" cranks that are so far outbound. Since it is an external bearing BB (lengthening the spindle) this may be partially the cause for the front derailleur not being able to go all the way out. Second, my new fangled SRAM info may be wrong, but perhaps the spacing of that crank is slightly different causing issues with shifting. But I do know you are using a SRAM derailleur with a Shimano shifter which can cause issues with the pull ratio, that may only work only with SRAM shifters. Its in SRAM's interest to only sell you only SRAM products. And lastly you are using a long cage rear derailleur with a double crank (its bad luck :) ) You absolutely need the correct length of chain when you do this, it sounds like the chain is too long. If you did the chain measurement by the books (pulley vertical in small cog, large ring) it might not be right since it assumes you have a short cage. Though long winded hopefully this may get you an idea on what you are up against, but with determination you can do it!
Tinkeric
05-10-08, 11:32 PM
You may smoothen it out with a component called a Shiftmate, which compensates for the different standards in the drivetrain. http://jtekengineering.com/shiftmate.htm
anti.team
05-11-08, 12:18 AM
A shiftmate isn't really applicable here, all his components are compatible.
I think the real issue here is the chain. 10sp chain is a little narrower and the 9sp chain may not be compatible with the 10sp derailleur. Someone will hopefully correct me if I'm wrong.
Retro Grouch
05-11-08, 06:30 AM
Help!! :cry::cry:
I'm presently building up my girlfriend's Ritchey Breakaway and am having a seemingly unsolvable drivetrain compatibility issue. I'm trying to run the following:
I think that you're on the right track. It sounds to me like you have a chainline issue. What's your rear dropout spacing?
giantxc
05-11-08, 03:16 PM
Thanks for the suggestion, turns out it was two idiotic problems. The rear derailleur was cross threaded and therefore not aligned properly and QBP sent the frameset with the wrong cable guide for under the bottom bracket shell. Works properly now.
BTW, I'm pursuing the weird build because I want to be able to put a mountain cassette on for a trip we have planned to the Alps this summer.
Wordbiker
05-11-08, 03:53 PM
BTW, I'm pursuing the weird build because I want to be able to put a mountain cassette on for a trip we have planned to the Alps this summer.
Model Number RD-6600-GS
Series ULTEGRA
Cassette Compatibility 10-speed
Maximum Sprocket 27T
Minimum Sprocket 11T
Maximum Front Difference 22T
Total Capacity 37T
Of course you can exceed this, but expect more wonky issues. I'd recommend an LX rear derailleur instead of the Ultegra.
Model Number RD-M581-GS
Series DEORE LX
Shifting Action Top Normal
Mount Type Drop-out
Maximum Sprocket 34T
Minimum Sprocket 11T
Front Difference 22T maximum
Total Capacity 33T
Don't worry about the long cage Ultegra derailleur. I have run them with 34t just fine.
Is your derailleur hanger straight?
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