SRAM Rival Cranks on 2010 Cross-Check - Need BB Spacers?
02-12-15, 04:08 PM
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SRAM Rival Cranks on 2010 Cross-Check - Need BB Spacers?
Apologies for cross-posting:
I've had my 2010 Surly Cross Check stripped and repainted, and I'm slowly putting it back together. When I broke it down, I noticed that the guy who'd installed my SRAM Rival Cranks and GXP Bottom Bracket had put one of the 1.5mm spacers included with the BB on the drive-side cup only (nothing on the non-drive side). I also recall him making an off-hand comment about it being tough to get my chainline set properly (the bike came with old-style splined cranks and internal BB).
The BB shell is, according to Surly, English-threaded and 68mm, meaning no spacers should be necessary per SRAM's instructions that came with the new BB. I've screwed in the BB cups and mocked the cranks up; I don't see any apparent issues.
Did the shop guy know something I don't? Have other folks with Cross-Checks noticed a similar issue? The Surly website is silent about the issue, which tells me the shop guy was off, but who knows?
Just trying to save a bit of time and labor. Thanks!
I've had my 2010 Surly Cross Check stripped and repainted, and I'm slowly putting it back together. When I broke it down, I noticed that the guy who'd installed my SRAM Rival Cranks and GXP Bottom Bracket had put one of the 1.5mm spacers included with the BB on the drive-side cup only (nothing on the non-drive side). I also recall him making an off-hand comment about it being tough to get my chainline set properly (the bike came with old-style splined cranks and internal BB).
The BB shell is, according to Surly, English-threaded and 68mm, meaning no spacers should be necessary per SRAM's instructions that came with the new BB. I've screwed in the BB cups and mocked the cranks up; I don't see any apparent issues.
Did the shop guy know something I don't? Have other folks with Cross-Checks noticed a similar issue? The Surly website is silent about the issue, which tells me the shop guy was off, but who knows?
Just trying to save a bit of time and labor. Thanks!
02-12-15, 08:18 PM
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Doesn't make a lot of sense - GXP cranks have their chainline set with the non-drive side bearing. The drive side just floats in the bearing.
02-12-15, 08:46 PM
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Yeah, I'm starting to wonder if he was just a bit confused. I've set it up with no spacers, and have now tensioned the derailleurs/cables; everything seems to be working just fine.
Oh well, guess I posted for nothing. Thanks for the input!
Oh well, guess I posted for nothing. Thanks for the input!
02-12-15, 09:14 PM
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got a question, if so, and i'm not doubting you, when the fixing bolt is torqued to spec does the drive-side crank arm bear directly or indirectly somewhere on the cup?
did some research and have an answer i can live with. DS spindle/cup interface is tapered. bearing floats laterally, with light contact fit between spindle/inner race and cup/outer race.
with the manifestly different approaches between shimano, campy, sram, and shimano having, to me at least, the most reasonable one. shimano must have a pretty ironclad patent on theirs to force the other guys to come up with such IMO, rube goldberg arrangements.
shimano, straight no frills, no taper, no hirth joint, spindle. same simple shoulder on DS and NDS arms that contacts inner races of bearings. NDS crank arm attaches with spline providing ample lateral adjustability and a simple pinch bolt (like threadless stems) to hold it all in place. they provide a threaded assembly tool to help adjust preload on bearings, but IME, again like the top cap on a threadless headset, not even necessary. and all accomplished wlth one hex wrench.
apologies for hijack, but thought from your last post you might be done here.
Last edited by hueyhoolihan; 02-12-15 at 09:31 PM.
02-12-15, 09:16 PM
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It appears to me that both drive and non-drive side cranks are supported by the rotating sleeve inside the cups/bearings. Does that answer your question?
02-12-15, 09:34 PM
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i agree with your explanation. thanks. 
Last edited by hueyhoolihan; 02-12-15 at 09:43 PM.
