Author Topic: Additional square BB protection  (Read 1876 times)


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Additional square BB protection
« on: August 23, 2023, 12:26:15 am »
About half-way into our 2000 mile tour this year, my square taper BB developed a creak. It was clearly the BB, since after arriving back home, I replaced it and the creak was gone (I also tightened the BB during the tour with no effect). I have had this happen before and although it did not affect the tour, it was annoying. The BB was relatively new. I assume grit worked its way past the seals of one of the cartridge bearings. I removed the seals of the bad bearing and found that the balls and retainer were intact.

I have always thought that an additional external piece of rubber or plastic might help to keep grit out. When replacing the BB, I discovered that a garden hose washer was the right size and has a rectangular cross section, so I place one on either side. Perhaps this will help. Has anyone else added something to the axle to protect the BB bearings?


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Re: Additional square BB protection
« Reply #1 on: August 23, 2023, 10:52:40 am »
Yes. On old TA and Shimano bottom brackets with traditional cup, cone and free ball bearings I got good results (over 40,000 kms without pitting) using V-ring seals next to the cups with a stack of O-rings between V-ring and crank to keep the latter lightly pressed against the cups.

This also works with TA Axix bottom brackets that have sealed bearings, but AFAIK not with Shimano UN55 and similar.


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Re: Additional square BB protection
« Reply #2 on: August 23, 2023, 10:55:33 am »
I smear some marine grease on the outside of mine, it gets replaced when serviced, it's clear to see after a year (Or two), when I wipe it off,  that the dirt hasn't penetrated. 
My current tub of grease is nearing the end, it lasted at least ten years, possibly twice that.  When I come to replace it, I might give this stuff a go