Wednesday, March 30, 2011

The Wheels Came Off

I've always had my fair share of issues with wheels. Lets face it, they are a core component of a bicycle and arguably get the most use and abuse. I'm a big guy and I tend to ride fairly aggressively, which stresses the key component, often beyond their limits.

This past season I've had numerous issues involving the wheels, ranging from those as simple as flat tires during races and as catastrophic as demolished wheels. Starting with the simplest, the flat tire, I had one in a fast crit for which I was able to get a neutral change without issue, a double flat in a cross race, which at the time I was leading and the very next day I had two flats in one MTB race that resulted in my first ever MTB DNF. The funny thing is that I'm a stickler for tire pressure and will always opt for higher pressure and live with the handling consequences. My thought is always that it's really hard to win a race with a flat tire and on training rides, I don't want to be that guy that everyone else has to wait for while they fix a flat. Learn to work with what you have; it will make you better in the long run.

The Ksyrium couldn't handle the pressure.

Beyond the simple flat, and one case of shredded sidewall on my trusty old Nokian MTB studs, I rolled a tubular cross tire off the rim in one race and I also dropped the chain and wedged it between the cassette as spokes such that it could not be extracted during another race. I also tore the free-hub body off from the hub-shell of my wheel in a late season single-speed cross race. Beyond those, I also had the displeasure of getting caught in a crash that happened in a cross race as I overtook a nervous lapped racer who crossed from one side of the trail to the other and then crashed in front of/into me. The other person off the front of the race with me plowed into me a punched a neat hole in my spiffy new Reynolds carbon-fiber tubular rear wheel.

Result of the patched carbon fiber rim puncture.

The puncture was hopefully primarily non-structural and I was able to patch my Reynolds rim though, with the help of some epoxy and some carbon-fiber cloth, which by the way is nearly impossible to cut into small pieces without it falling apart. I finally gave up and just inlaid some of the carbon fiber strips across the hole, embedded in the epoxy resin. I've had good luck then using a piece of slick, texture-less vinyl over the top of the wet epoxy which I then lay a piece of half inch closed cell foam over and wrap with an old inner-tube section to mold the surface of the patch to match the rim surface. The result is a smooth repair that matches the rim's profile nicely.

This is why I think rim brakes are stupid.

Most recently, last Sunday in fact, my lightly used Power Tap wheel laced to a Mavic Open Pro rim decided that it had had enough and split on the brake track. I'm no stranger to the catastrophic failure of Mavic rim brake rims. In fact, I've got a couple other Open Pro's in the basement that could be long lost twins to the one on my Power Tap wheel. The up side to this story is that it happened literally as I was turning onto my street to finish my ride and not when I was 20 plus miles from home. Also, I noticed it and was able to air down the tire before the pressure blew the rim apart, sending shards of sharp aluminum spiraling everywhere. That is always a really fun sight and sound. Who would have guessed that using a primary structural component of machine as a wear item could lead to problems?

1 comment:

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