Saturday, August 8, 2009

London Edinburgh London 2009 Stories -- Crank Problems

You've heard the advice many times -- don't change anything on your bike before a big ride. Still, I had a lot of miles on my Coho's drivetrain, so I had Ed, my trusty mechanic, put on a new cassette, chain, as well as an FSA bottom bracket and crankset, which is one of those modern designs with the outboard bearings. All seemed fine on the 100-mile test ride here in the states, and on a 20-mile trial run on the LEL course.

So what happens on the ride itself? I'm probably 15 miles in and I can no longer shift into the large front ring. Thinking I had a derailleur or cable issue, I stop to check things out. The crankset now has as 1/4-inch of side-to-side play -- so much that it slides to the right out of range of the front derailleur's ability to put the chain on the large ring. I knew how to tighten it -- loosen the bolts on the left crank arm, tighten the crank arm cap bolt. But I didn't appreciate the subtleties involved. I should have loosened the crank arm bolts more. The volunteer mechanics along the way were more like me -- they knew all about the old school square taper bottom brackets, but were pretty clueless about these new-fangled designs.

Bottom line: I never really got it right and had to stop, sometimes as often as every 100K, and readjust. In my lowest moments, I wondered whether this mechanical issue would be a show stopper. But I lived with the annoyance and got er done. Lesson learned -- leave well enough alone before the ride or get a quick lesson in roadside repair beforehand.

Apart from that issue, the bike performed flawlessly and was a delight for the entire 1400K journey. A special thanks to Chuck for building such a fine randonneuring machine.


Doctor on a bike said...

I keep looking longingly at those outboard bearings and keep thinking they'd be nice. I may yet go for it, but I'll time the decision appropriately thanks to this advice.

Cap'n said...

I was very thankful that you had that recurring mechanical problem with the crank. Every time that you stopped to tighten it I would catch up with you again.

WMdeR said...

Dear Mike,

I had the same experience on a traditional bb/crankset on a recent 280mile ride. I had almost 1K miles on the BB installation when it worked loose on a 30mile climb. DNF. Sometimes you just get unlucky. Congratulations on your finish!

Best Regards,

William M. deRosset
RUSA 2401