Stylo GXP problem

[JRogers]

I was coming back from a ride today and noticed a slight noise coming from the cranks. Only had a minute or two to go, so I just rode it in.

Get off the bike and see that the non-drive crankarm on my Stylo GXP cranks is pretty loose. This happened once before and I've checked it every now and then and every time it was fine.

When I tightened it the cranks became very hard to turn. I cleaned the interface, the bolts and all that. Put it back together and it's a bit better but the issue is still there- it spins until some actual tension is put on the bolt and then it starts getting hard to spin.

Any ideas?

[binary visions]

What you're saying, is when the crank arm is tightened down onto the bottom bracket spindle (the 8mm bolt), the crank arms become hard to turn?

Check for some kind of mechanical interference. When you tighten down the crank arm, I'd bet a dollar that the inner part of the crank arm down by the bottom bracket is binding (rubbing) on either the frame or the bottom bracket cup.

I had a too-short BB spindle at one point and couldn't tighten down my crank arm all the way without it binding on the frame. The issue stemmed from installing a chainguide but still using a short (113mm) bottom bracket spindle - it wasn't long enough to accomodate the chainguide and still give me enough room to fully install the crank arm.

The fix is that you need a new bottom bracket. I tried riding on mine and ended up partially stripping the splines - it's a good thing I was going slow when it happened.

[JRogers]

What you're saying, is when the crank arm is tightened down onto the bottom bracket spindle (the 8mm bolt), the crank arms become hard to turn?

Check for some kind of mechanical interference. When you tighten down the crank arm, I'd bet a dollar that the inner part of the crank arm down by the bottom bracket is binding (rubbing) on either the frame or the bottom bracket cup.

I had a too-short BB spindle at one point and couldn't tighten down my crank arm all the way without it binding on the frame. The issue stemmed from installing a chainguide but still using a short (113mm) bottom bracket spindle - it wasn't long enough to accomodate the chainguide and still give me enough room to fully install the crank arm.

The fix is that you need a new bottom bracket. I tried riding on mine and ended up partially stripping the splines - it's a good thing I was going slow when it happened.

Your description of the problem is correct and there does seem to be some contact (I can see wear on the bearing seal).

However, I didn't notice this problem before now, I didn't change the setup at all and (most importantly) this is the OEM crankset on the bike- Prophet 1000. I'm sure that if too-short spindles were an issue, I'd have heard about it.

[binary visions]

Just because it isn't widespread doesn't mean it's not a problem with yours :)

You could measure the spindle length and see if it's out of spec. Could also be that the spindle wasn't properly set in the BB and it's shifted towards the drive side, leaving the non-drive side spindle too short.

Can you see the physical contact or are you just noticing some wear on the bearing seal?

[JRogers]

Well, I reset the crank spindle, measured it (seems okay) and reinstalled. Same issue. The friction seems like it's gone down a bit, but still seems excessive. It seems like excessive drag is coming as the crank presses against the dust seal/bearing. The non-drive bearing is a lot more worn (rougher) than the drive side.

I DID find that the shop that built the bike appers to have put a spacer on the wrong side of the BB cup. According to Cannondale documentation, there should be a spacer between the BB shell and front derailleur mount (e-type), instead, they put it on the non-drive side. I'll change this and see if it helps...