Friday, September 3, 2010

going fast and breaking things

I set what I'm thinking is a good benchmark for me at the local time trial, riding cannibal. I averaged a hair over 24 mph on the 9.75 mile course. I never claimed to be a great time trialist - or even a good one, but I was happy with this. The last time I attempted to set some sort of benchmark on this course was in 1992 - yes, 18 years ago. They've shortened the course a bit since then. It used to be a complete loop of 10.8 miles. Now they start at one point and finish a mile earlier into the same loop, cutting out an intersection that has been fitted with a stop light.

18 years ago my cannibal PR was 26.02,or a hair under 25 mph. This Wednesday I averaged a hair over 24 mph. Intrigued by this, I checked my current PR against my old PR full aero. Again, the difference is about 1 mph.

Is losing one mile per hour after 18 years ok?

I blogged earlier in the week about racing two 'cross races last weekend. One with a heinous loose rocky steep long downhill and the other flat but scattered with roots. I survived the death descent on saturday well, but the roots on sunday weren't so kind, giving my Mavic Classics SSC clinchers a flat rear and a tweaked front. Yesterday I finally got to checking out the wheels. The rear is fine, no loose spokes, completely in true and round. The front though...

When I pulled off the tire I was shocked to see the sidewall creased, folded over inside the rim.

I've fixed wheels with this sort of damage before - quite successfully. I have a ten-year-old set of Rolf Vector Comp clinchers that have conservatively 50,000 miles on them and required little maintenance. I've rebuilt the hubs, trued them occasionally, and in one instance had to pry the sidewall straight after hitting a pothole. You do this by adjusting an adjustable C wrench over the sidewall so there is as little play as possible, and gently work along the sidewall to straighten it. Yes, this works, I've done it on more than one clincher. I finally had to retire the rear Vector Comp this summer after I nailed a pothole while drafting a truck through lawrence.

The alloy on the Mavic SSC rim is considerably less ductile than my other wheels, and when I tried the C wrench, it simple tore the metal. Here you can see the tear along the base of the sidewall, as well as the crystalline stress fractures.


This picture shows the tooling mark, the chipping of the ceramic coating, and what appears to be a separation along the sidewall-rim seam.



I'm not too upset about it, I think I paid $100 for the pair, though I've been telling people I traded a bag of weed for them. The only question is what do I replace it with? I'd like to get something that gives at least the suggestion of an aesthetic match without going nuts on the cost. Black Open Pro rims run anywhere from $70 to $120 depending on whether I want the base level, the CD (Couche Dure, or Hard Anodized), or the ceramic. I'm thinking I don't want to spend alot of money on a 'cross wheel.


1 comment:

Miff said...

You TT ANIMAL......loving it. ;-)