Help with bottom bracket spacing please
Feel slightly embarrassed posting this as I can't think of many other bike associated questions that I can't answer via a google search... :oops:
We bought a discounted Scott CR1 Pro frame from Westbrook a few months back (the OH's bike), which was built up and has been used ever since.
This morning whilst bored I had a bit of a play on it and noticed the non drive crank arm was loose. The pinch bolts were not tight so wound in the plastic nut only to have it shear.
A bit more playing seems to suggest that the bottom bracket needs a 2.5mm spacer as when the crank axle is nipped up there is play and a noticeable gap.
Not sure why I didn't notice this when I built it and can only think that the axle wasn't all the way through at the time.
The problem is that is has a press fit bottom bracket and I don't really want to take it out if I don't have to.
The crankset is a Shimano 105 5750 and the frame was supplied with bottom bracket fitted.
Do I need to take the bracket out to see if there are any spacers fitted or can I buy one that fits on the outside of the bracket on the axle of the crank?
We bought a discounted Scott CR1 Pro frame from Westbrook a few months back (the OH's bike), which was built up and has been used ever since.
This morning whilst bored I had a bit of a play on it and noticed the non drive crank arm was loose. The pinch bolts were not tight so wound in the plastic nut only to have it shear.
A bit more playing seems to suggest that the bottom bracket needs a 2.5mm spacer as when the crank axle is nipped up there is play and a noticeable gap.
Not sure why I didn't notice this when I built it and can only think that the axle wasn't all the way through at the time.
The problem is that is has a press fit bottom bracket and I don't really want to take it out if I don't have to.
The crankset is a Shimano 105 5750 and the frame was supplied with bottom bracket fitted.
Do I need to take the bracket out to see if there are any spacers fitted or can I buy one that fits on the outside of the bracket on the axle of the crank?
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Comments
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A Shimano HT2 crankset with a pressfit Shimano BB86 bottom bracket doesn't need any spacers unless it's a triple.
I know this because I have a CR1-SL, and have fitted both a 105 5603 triple crankset, and a Tiagra 4500 double.
So if your chainset's a Shimano double of some kind I suggest you loosen up the pinch bolts, remove the little plastic cap then remove the LH crank. Thoroughly clean the mating surfaces / splines and apply a little grease before reinstalling. Try to persuade the non drive side crank fully onto the spindle before tightening the little plastic cap* only finger tight to preload the bearings. Then fully tighten the pinch bolts, alternating between them rather than doing one up completely first.
* the new one you've bought to replace the one you've mangled, obv.0 -
Don't I feel silly
Yes of course you are quite correct.
Not entirely sure what I was doing this morning, but a break and re-look had it all back together correctly.
Borrowed a plastic cap from my n+1 mtb and all good
Cheers for pointing out the obvious.0 -
Splendid! I suppose you only really need the plastic cap to preload the bearings so you can move it from bike to bike as required0
