Play in Bottom bracket

If i hold the end of each crank and move from side to side there’s about 1 to 2mm play, the bottom bracket is OSBB on a 2015 Tarmac.

The bottom bracket is still quiet and otherwise it’s fine, however I’m planning on a 106 mile ride on Saturday, should I have any concerns ?

1-2mm is a LOT of play for a bearing. Are you saying that the crank slides that much or that you can see the bottom bracket moving? I would definitely get it looked at. Depending on the issue you could do irreparable damage to your frame.

EDIT: Also, what cranks do you have on your bike? It could be something as simple as tightening a couple of bolts on the cranks. Or maybe a bearing preload.

Concerns? No…but I’d definitey replace it. I sincerely doubt it’s going to blow up or disintegrate in 100 miles if you’re just noticing play now, but play means it should be replaced.

BBs are cheap. If yours is threaded, it’s a super easy task. They basically just screw right out, screw a new one in (you’ll need a stupid task specific wrench thiugh, and a second one for the little plastic cap on the non-drive side crank as well. Both are fairly cheap and on amazon).

If it’s press fit…I’d just bite the bullet and take to a shop and have it done right…

Edit: OK I just looked up what an OSBB is…yea looks like it’s press fit. I’d take it to a shop, sadly. If the ride is important to you, if ‘feels’ ok while riding, and as noted above it is definitely the cranks shifting a bit and not the BB cups themselves…I’d just ride it if the shop cant replace in time. The bearings are toast; no reason to worry about abusing them further.


OSBB’s are pressfit

Yup. See my little edit above

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S Works cranks and the crank bolts are tight with no visible movement in the bottom bracket, there’s one strange aspect, if I rotate the cranks through 12 to 3 to 6 to 9 o’clock the play goes from zero to 1 to 2mm.

I’ll get it booked into my LBS and get it fixed

Hmm that’s strange that it goes away at certain angles. I would just be worried that the bearing are crooked in the bottom bracket and could ovalise the cups and damage the frame. It’s hard to say with no pics/video but I would at least take it to your LBS to get looked at to be sure.

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Do not ride the 100 miler. Take it to the shop.

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All sorted and thank you all the replies and informed insights.

I managed to find a local mechanic who sorted the bottom bracket while i waited, which I appreciate was very lucky considering the demand on bike shops due to Covid 19.

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Good! Glad it was able to be fixed quickly and without much hassle.

Did the mechanic tell you what the issue was? Just for my own curiosity

He replaced two lots of bearings. £35 well spent which leaves me to enjoy tomorrows ride. Happy days!