Saturday, May 5, 2012

BB Watery Grave - Fix O Rama

While cleaning and doing a little drivetrain maintenance on Racer Boy Ian's bike today, noticed the crank would barely spin.  Popped the chain off, another test spin - yup - BB bearings were toast.  Two years of Pacific Northwest mountain' bikin' cooked 'em.  Seemed a little early though, especially since I transfered the crank and BB to this latest frame a few weeks ago and they felt fine.

I pulled the crank out and discovered the left bearing was okay, the right one was pretty rough.  Bottom bracket was also full of water, from washing the bike and general Wet 'N' Muddy riding.  I should also mention, if you're familiar with Shimano BB sets, bike was built up minus the plastic internal sleeve - which also helps protect the bearings.  I cracked the sleeve during the original build and tossed it.  So, maybe two years under those conditions seems acceptable.

Dead BB means no riding, quick fix in order.  Fine folks at Kirkland Bicycle, located strangely enough in Kirkland, had a Shimano BB set in stock.  After a quick install, this time with plastic sleeve in place, bike was rolling once again.  Oh yeah, I also drilled a small drainage hole in the bottom bracket shell to allow future water to escape - I hope.

Being old school bike mechanic with shop days from '81 - '84 (or so) - with knowledge of rebuilding old school bottom brackets that required a pile of tools and a bit of experience - these modern cranks still amaze me.  Sure, the bearings are not rebuildable; but with so few parts, light weight, and ease of assembly - impressive.  Even this LX crank, lower on the Shimano level of coolness, is a really great crankset.  If something like this showed up at the shop in '82, we'd have thought it arrived via Area 51.

Technology marches on, as well as riding - which is on the agenda for tomorrow.


  1. I feel your pain. Seems BB is one of the high time demand areas on a bike. My bikes need hosing down about every other ride, and water gets in the BB. I seal the area where the seat post grips around a few other potential areas. Now even with that about every 6 rides where water is involved I pop the seal on the sealed bearing and pack with grease. Happy rides to you and Ian the racer man.

  2. We get plenty of wet rides here in Washington, plus I hose the bikes off often - no way around it. Water seeps in via the seatpost, frame air vents, and who knows where else. I've done the pop the seal and re-grease trick in the past, but over the last few years, just buy new bearings instead.

    Overall, everything holds up pretty well, considering what we put it through...

  3. Funny, I thought I was the only person who drilled a drainage hole. I put a little piece of tape over the hole until I wash the bike.

  4. First bike I've done that - cheaper frame - not worried about it, so drilled away. It had a fair amount of water in there. No wonder the bearings were toasted.

  5. Oregon has the same issues. After cyclocross season in Portland my wife's and my Redline had mud in the bottom bracket area, but my son's Focus with the large factory drain hole was clean. I drilled some holes and replaced my crunchy 3 year old bearings. FSA and Raceface external bearing bottom brackets are designed with replaceable bearings so I got some Enduro bearings for half the price of a new BB and pressed them in.