Noisy drivetrain after grpset change: spacer needed?
6 weeks ago I upgraded from an all SRAM Rival setup (+ Truvativ Elita crankset) to an all Force & Red setup
Only thing not changed was the BB
Ever since the groupset change I've found it impossible to tune all the gears.
I either get rubbing on the front mech or really severe cross-chaining
There's no equilibrius sweet-spot where everything runs smoothly. It's as if the front mech doesn't have enough room to accommodate all shifts in from the rear. For example: if you adjust for low gears then you'll sacrifice the high gears, and vice versa.
Plus, even when the gears do run to the best of what's possible - with zero mech rub or cross-chaining - it's extremely NOISY....'clunk clunk clunk'... as the sound of the chain seemingly grinds through the rear mech pulleys, cassette and crankset.
I'm at a complete loss...
My only thought is that the new RED crankset might need a spacer between it and my old BB and/or maybe NOT adjusting the chain length when I went from 52/38 to a 53/39 might have introduced a problem?
Current drivetrain component list:
RED Crankset (2x10 - 53/39) & Red Levers; Force Cassette, Force Front/Rear Mechs & a KMC X10 SL Chain
All help & advice much appreciated.
Thanks
Only thing not changed was the BB
Ever since the groupset change I've found it impossible to tune all the gears.
I either get rubbing on the front mech or really severe cross-chaining
There's no equilibrius sweet-spot where everything runs smoothly. It's as if the front mech doesn't have enough room to accommodate all shifts in from the rear. For example: if you adjust for low gears then you'll sacrifice the high gears, and vice versa.
Plus, even when the gears do run to the best of what's possible - with zero mech rub or cross-chaining - it's extremely NOISY....'clunk clunk clunk'... as the sound of the chain seemingly grinds through the rear mech pulleys, cassette and crankset.
I'm at a complete loss...
My only thought is that the new RED crankset might need a spacer between it and my old BB and/or maybe NOT adjusting the chain length when I went from 52/38 to a 53/39 might have introduced a problem?
Current drivetrain component list:
RED Crankset (2x10 - 53/39) & Red Levers; Force Cassette, Force Front/Rear Mechs & a KMC X10 SL Chain
All help & advice much appreciated.
Thanks
0
Comments
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Your chain length will have increased slightly if you're going big big with your gear selection. Are you using a YAW front derailleur or Force/Red 22 one? These don't have a trim function as such and instead pivot slightly. It makes it difficult to get no interference when cross chaining, but they are smoother when changing chain rings.
If your chainrings are both the same type of BB, why would you need a spacer?
SRAM is "designed" to cross chain without interference, but I wouldn't recommend it other than for very short bursts when changing on the front would mean changing on the front again within a minute or two.I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.0 -
The new chainset could need a different spindle length BB? I upgraded a truativ chainset on a MTB and it needed a 5mm shorter BB.0
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What sort of bottom bracket do you have? Make sure you follow the instructions that come with the crankset for that type of BB. Sometimes different Sram cranksets will use a different spacer setup. If you have a front shifter that does not have the trim positions (so it only has two positions not three) then you will almost certainly need to make sure that you use a Yaw front mech. Make sure that the chain is long enough. Sram recommend the big big plus a link method but I've always found using the longest chain method to be the best:
http://www.slowtwitch.com/Tech/Chain_Ho ... _3279.html
Make sure the rear mech is spaced the correct distance from the cassette (adjusted using the "B" screw).0
