iozhik

Hello!

I've been hearing a clicking noise with a frequency comparable to my pedalling frequency. It's been driving me mad for a week now.

Thinking it was the seat, I removed the seat post, greased, etc., but the noise persisted.

I took a look at the bottom bracket (Shimano BB51) and noted it has a 2-3 mm play: I can push the crankset and the pedal at the other end will come out by 2-3 mm...

Since I am new to the forum I cannot yet post pictures, so I've had to upload it here imgur.com/a/9MnqA49 (the forum also does not allow to post URLs until one has 10 posts......)

Is the play room due to some washer/ring which vaporized or broke and fell? Is it a matter of tightening? If so, what? Should I just get a new BB51 and install it?

I am new to bike repairs, but am willing to spend the time and a bit of cash to get the material+tools and to learn (and I have another bike I can use while I horse around with this one). Any hints will be most welcome!

Many thanks in advance!

PS: a decent clean-up is long overdue....

iozhik

scratch that, I'm an idiot. Could get rid of the 2-3 mm play by loosening the 5mm allen head screws in the pedals, pushing the pedal in, and tightening them again.... Will now go for a ride to the village cafe for breakfast and keep my fingers crossed to see whether the clicking noises vanished....

seedsbelize 

Welcome to the idiot's club. EVERY time I build a bike, I invariably cable the brakes backward. The most recent one I caught almost immediately, so some progress is being made. One time I even mounted both crank arms in the same plane. Noticed it on the attempted test ride.

Andrew R Stewart 

Shimano's UN-51 BB version is rather old, it could be that the bearings are just wearing away. Andy

lukedunk

That is hilarious and made my day.

iozhik

This was a refreshing read. Idiots of the world, unite!

In the end the click went away, but lucky as I am, and for the first time ever, I went out and broke a spoke. So this month I'm learning quite a bit of bike maintenance by force.

iozhik

Thanks for the feedback! I gathered from a well-intended google search that the BB52 is the successor.

If the noise comes back and is clearly identifiable with the bottom bracket, I guess that's the one I'll have to aim for (?)

Trevtassie

UN55 or UN26

iozhik

Superb! Thank you very much.

Heck, I'm looking forward to reaching the stage where I can do my own bike maintenance (and am more than happy to pay the price to get there).

Cheers from rainy central Europe!

Metaluna

Those are square taper bottom brackets. The imgur photo that the OP posted shows an external bearing Hollowtech II BB, i.e. a Deore SM-BB51, like this one:

https://planetcyclery.com/shimano-ho...bottom-bracket

iozhik, pretty much any "Mountain" style Hollowtech II bottom bracket with mountain bike branding (e.g. Deore, Deore XT, Alivio, SLX, etc.) should work, such as the SM-BB52 that you talked about. The "road" style Hollowtech II models (with road branding, e.g. Tiagra, 105, Ultegra, etc.) look almost the same but are a bit shorter so might not fit your crankset properly.

The picture you posted to me looks like your left crankarm was coming loose from the crank spindle. The gap you correctly highlighted in the pic should not exist and the crankarm should be pressed up against the bottom bracket cup. It sounds like you managed a good enough fix by pushing it back together and tightening the two pinch bolts, but there should be a small plastic or metal cap on the end of the spindle with what looks like a star-shaped impression in it. That is the preload screw. You are supposed to loosen the pinch bolts then tighten this screw (using a special tool) until the crankarm presses against the left BB cup with a little bit of force (aka preload). Then you tighten the pinch bolts to the correct torque.

But to keep this problem from recurring, you really need to do that preload procedure and then torque the bolts properly (I think the torque spec is around 13 Nm).

This tutorial should give you an idea of what I'm talking about:
https://www.parktool.com/blog/repair...ession-slotted

Trevtassie

Right you are, I just looked up the bike itself from the model name, and didn't look at the imgur link. The European on must have had hollowtech fitted .
I can't see the little plastic spacer ring that goes between the crank and the bearing either, unless it's hiding in there somewhere?

iozhik

Metaluna, thanks a bunch for your detailed and pedagogic answer!

I'll make sure to steer towards the SM-BB52 or equivalent when the time
comes.

A couple days ago I placed an order which should hopefully reach me
these coming days, part of which is indeed the tool to tighten the
preload screw. Thanks a lot for the feedback though. It feels so likely
to be making stupid mistakes... I take it though as an investment or
rather a guarantee that I'll be able to properly maintain a more decent
bike whenever this happens Thanks also for the Park Tool tutorial.
Their set of videos plus those of GCN are being educational beyond my
wildest dreams!

Cheers!

iozhik

Apologies about the plaintext link.... As a new user I have to pay the penalty of not being able to upload images or paste URLs. I think after 10 posts or so I will be granted the privilege.