Bearing removal

[Pingu]

Below is a pic of the TA bottom bracket from Mrs P's Roberts bike. The cartridge bearings are firmly attached to the spindle so that I can't remove them by hand. Is it OK to twat them with a hammer to remove them? Nothing else seems to be holding them on.

I thought I'd better ask for advice first 


IMG_5549_01 by The Pingus, on Flickr

[Torslanda]

If they're being replaced, yes. I would support the bearing on the vice and use a block of hardwood under the hammer.

NB. It isn't OK to fit the new bearings in the same way. New bearings must be pressed into place using a tubular fitting which exerts pressure only on the centre of the bearing. At a pinch a deep socket with a mallet will do. Lack of finesse will severely shorten bearing life.

[Pingu]

Thanks T. They are indeed being replaced.

[tatanab]

I did this with a Royce bottom bracket a few years ago.  Leave the spindle in a freezer overnight before fitting new bearings will help.

[Torslanda]

Don't handle the above without gloves!

[Mrs Pingu]

They took quite a lot of twatting with a hammer. The spindle is now in the freezer. The closest thing we have found to help tap the new bearings on is a Park Tool cassette tool thingy.

[Feanor]

Whatever you use, make sure it's pushing against the *inner* race of the bearing, directly where it contacts the spindle.
So any tube that's a close fit over the spindle.
Make sure it's *not* pushing on the outer race, and transmitting the force across the bearing.

As T. mentioned, having a rummage through a socket set can often find something, but it will likely need to be a deep socket to fit down deep enough.

What's the OD of the spindle at the widest part where the bearing sits?

[Mrs Pingu]

These are the bearings https://www.thebigbearingstore.com/6903-2rs-6903-zz-radial-ball-bearing-17x30x7/
So presumably the spindle is 17mm or thereabouts. (The spindle is now in the freezer and the vernier calipers are in the beer cellar shed.)

[aidan.f]

The old bearing can be stacked over the next one and  pressed into service to fit the new ones. As up thread use a socket or thingy that presses down only on the inner journal. IMO the outer journal won't be putting excessive force on the new bearings. Cos the old one is worn. I suppose you could take an angle grinder to the outer for full assurance.

[Mrs Pingu]

The old bearing can be stacked over the next one and  pressed into service to fit the new ones.

Given that we could barely get the old bearings off in the first place, how would we get rid of the old bearing if we used it to fit the new one?

[mzjo]

Dropping the new bearings in a saucepan of oil at 80-100° for a few minutes will help them on if they are tight but be careful with the hot oil, use suitable devices and gloves for handling them and be careful to keep this well hidden from the OH if doing the operation in the kitchen.

Of course an induction heater for bearings would be nice but a bit pricey for one bb. I have also used a bit of steel stock suitably warmed for crank bearings which worked very nicely and didn't seem to harm the bearings.

I have played with a Stronglight bb of this design but that came apart and went back together by hand without any forcing.

[Polar Bear]

The old bearing can be stacked over the next one and  pressed into service to fit the new ones.

Given that we could barely get the old bearings off in the first place, how would we get rid of the old bearing if we used it to fit the new one?

Ream it out a tad.

[Feanor]

Reaming out the inner race of a bearing is surprisingly hard to do!
The bugger just spins instead of staying put and getting reamed.

You need to be able to clamp the inner race firmly enough to go in with the reamer, and that's usually not too easy.

[Mrs Pingu]

I did this with a Royce bottom bracket a few years ago.  Leave the spindle in a freezer overnight before fitting new bearings will help.

This worked a treat 

[Mrs Pingu]

Managed to get it all back together without loss of limbs, breaking anything or having a domestic. 
Hopefully it all works on the shakedown ride.