Press fit BB creaking

LBS fitted new, shorter XT cranks on the GF’s bike the other week.

First proper ride yesterday and towards the end of the day, on the long climb back to the van the cranks started creaking like crazy, to the point she said she could feel the vibrations through the crank.

Annoying as the old Sram cranks and bottom bracket didn’t make a noise for the last 4 years… In fact the bearings were still good.

Anything I can do to sort it before I have to go back to the shop…?

Basic bike tools, but no flanged hitty thing or bearing press.

Have already removed and re-greased the cranks.

Press fit creaking is usually caused by the bearing shell moving against the frame. Cause is almost always installation without anti-seize (preferable) or grease (second option if no anti-seize available) in between frame and BB. If BB is loose in frame (BB can be installed with almost / close to hand pressure only), then also locking compound / bearing installation compound (Loctite etc) may come in question.

I would wager that the installation of the BB was done dry, and now it is moving and creaking. Likely the BB should be taken out again and reinstalled with antiseize. I would take it back to the shop that did the job and tell them it creaks mightily. Some BBs are not meant to be taken out and re-installed, if they have a plastic shell it may crack upon removal. Shimano BB has a plastic shell and is not easy to remove intact, especially with bodged tools.

They all do that sir.

Thanks @mrauer

Shimano BB.

Looks like a drive back north to Perugia next week. Will give the guy a call tomorrow.

Just give up now and order a screw-together BB…

You mean the Wheels Manufacturing threaded thingy?

Seen that recommended a few times, but does it not add extra width to the BB/Q Factor?

Will that work with the cranks I have on there? New cranks fit without any spacers.

Have you tried regreasing the pedals? Or even trying a different set of pedals?

If it’s a plastic housed shimano pressfit, then it’s unlikely to creak.

You mean the Wheels Manufacturing threaded thingy?

Seen that recommended a few times, but does it not add extra width to the BB/Q Factor?

Worked fine with the existing crank in my case.

Have you tried regreasing the pedals? Or even trying a different set of pedals?

If it’s a plastic housed shimano pressfit, then it’s unlikely to creak.

Pedals are removed after every ride and usually nicely greased.

GF said she could feel the vibrations of the creaking through the pedal…. Was occurring on the drive side, on the down stroke and it was loud.

Removed and greased the cranks today.

I’ll give the pedals a butchers tomorrow and take the bike for a ride and see if it occurs again.

LBS is 60km away in Perugia so I’m a bit loathed to have to travel back there….

Worked fine with the existing crank in my case.

Good to know. Fanks.

Cheers guys….!

The Wheels Manufacturing BB works with XT cranks just fine. Makes no difference to the q-factor.

I’ve got one in my Arc and it’s been faultless.

As you say, the cups screw together which prevents the flex that you get with Shimano press fit BBs, particularly in a carbon frame.

The Hope one works in the same way, although needs a special tool to install.

check the chain ring bolts too. If one is slightly loose it can cause a creaking noise.

If they are the current generation XT cranks I’ve had the chainring creak because the lock ring wasn’t tight enough.

What bottom bracket is it?

I’ve had quite a few bikes with press fit and not one of them has creaked

If they are the current generation XT cranks I’ve had the chainring creak because the lock ring wasn’t tight enough.

Yup, current.

I guess it doesn’t make sense that the plastic shells are creaky….

Annoyingly I have the tool to fit the chainrings on Shimano cranks (it also fits Shimano threaded BBs), but I don’t have a spanner big enough nor do I have a vice in the van….. Doubt I’ll get enough torque on there with my plumbers pliers, but worth a try.

It could be that they overtightened the compression cap when they installed the bottom bracket, it’d be easy to check if you have a tool.

Don’t have that tool (I use a pair of scissors wedged in there), but I did do it up pretty tight today when I refitted the cranks.

How much should it be tightened?

Finger tip tight, only tight enough that there is no play in the cranks, if you overtighten it then you end up crushing the bearings or at least add resistance to them moving.