Bicycle Mechanics - bottom bracket removal / replacement query?
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My RIH heavyweight around-town utility bike started making strange noises in the BB area yesterday.
Figuring (correctly) that it might need a BB overhaul, I starting going at it this morning.
But I am stumped. Unlike other BB I have tackled, this one (which I have to assume is pretty cheap) has no apparently way of removing it. on the non-drive (LH side there seems to be a rubber gasket of some kind.
on the RH drive side, once I removed the crank, there was nothing - just open air and exposed ballbearings.
But there seems to be no cups, no slots - nothing to attach a wrench to to remove the whole thing.
thinking it might be some kind of friction fit, I gave it a mild tap with a mallet. But that didn't produce any spectacular results.
12-08-10, 12:10 PM
It seems as if you have a pressfit bottom bracket. Given the type of cable guides it seems kind of odd that the bottom bracket is not a screw-in type. Did you buy this bike new or used? If used perhaps someone mucked up the BB shell threads and found a press-fit type one that worked.
Because it is not in front of me to actually checkout hands on it is hard to make a recommendation on what to do...it is safe to say however that you can't go wrong taking this to a "Good Local Bike Shop"...try one with an old school flavor to it.
I bought it used in France from a Dutchman.
It's not a top end RIH by any stretch. But I will follow your advise and drag it to an LBS.
12-08-10, 03:54 PM
Hi Pete, Yes what you have is a press in BB. You can remove by using a mallet to drive out the axle with one of the cups and then put the axle back in (without the cup & bearings) and again with a mallet to drive it out. You replace it with another press in BB set ( need to order thou a LBS ) or if the BB has treads see about using a seal BB ,just match the axle size.
12-08-10, 04:08 PM
what kind of mallet? you need a bit more than a 'mild tap'. if you have some extra crank bolts I would screw a set in all the way then use a peice of 2x4 and my 'truckers hammer' to tap them out. (tap is a realative word here it does take a bit of elbow grease)
as for new bearings if you have a industrial /truck repair supply house (there used to be place near me in Boston actually called South shore Bearing) you might be able to walk in with your old bearings and spindle and walk out with new bearings.
these are 'sealed' bearings I think bikeman is refering to a cartridge BB. VO makes a nice one that does not need threads in the frame but it may be $$$$ for you
12-08-10, 04:44 PM
Since you list your location as Toronto,
+1 on looking in the yellow pages or
on the internet under Bearings. As
stated above, you need to have with you
your axle and at least one of the intact
old bearings to match size and fitof
both inner and outer diameters.
I've personally never run into this.
Also, dose the assembly with penetrating
oil (PB Blaster--as seen on TV) just prior
to your attempts to extract the bearings
12-08-10, 05:20 PM
OH BTW I would try removing the drive side first. it looks like it is already destroyed so practice with it.
12-08-10, 07:47 PM
You need to whack the axle with a mallet to remove one sides bearing, then reinsert and remove the other. Those are standard cartridge bearings that you can get through mail order or your local shop. It is a really simple system to service.
I've seen these type on BMX bikes, where the sealed cartridge bearings are pressed fitted directly into the bottom bracket shell. +1 knock em out, buy new at industrial bearing house, re-install. When re-installing do not transfer force through the balls.
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