Sunday, February 21, 2010

Tire Casing Failure

I've never had this happen before, but the casing on one of the Kestrel's tires let go today. I'd mentioned previously that the tire was looking distorted in one spot, and I could hear (not really feel so much) the difference as that spot crossed over the roller drums.

Inflated, it looked as if the tube was folded over in that spot, causing the tire to distort, and it was worse with higher pressure. But really, it was just coming apart. The tube was clean -- no creasing or anything when I pulled it all apart. Still, the casing split diagonally across the tread of the tire, and lots of little nylon fibers tufted out of the split as the tube tried to push its way through. On the road, this would have been a catastrophic failure, but I'd heard it coming for weeks, so I doubt it would have caught me off guard. I tried to take some pictures, but pictures of a flat-black tire with some small and out-of-focus indications of damage aren't very interesting, as it turns out.

The tire was 3-4 seasons old, so no big loss or surprise. It also had a flat caused by a tiny plastic shard a couple of seasons ago, and that little blade may well have weakened the casing in such a way that it ultimately let go. I'd put money on that being the root cause, actually.

I'm not going to rush on replacements, since there are a couple of months left before I usually start getting out on the road, and because I have two other road bikes to choose from when I'm ready for outdoor riding. Still, it's hard to see my favorite bike sidelined with no rear wheel.

In the mean time, today I slapped the Motobecane onto the trainer and put a little over 10 miles on it. It has a very different feel than the Kestrel -- softer, roomier and mostly more comfortable. I would like to be able to scoot the saddle back a smidge further, but that'll take a new saddle, since the old Brooks Professional has rails that limit travel. And though that saddle has come a long way in breaking in since I first bought it, it's still not as comfortable as the San Marco Regal on the Kestrel.

The difference in feel aside, the Moto worked really well on the trainer. The wheelbase is close to that of the Kestrel, so it fit the current spacing of the drums, which was handy. It's substantially more stable than the Kestrel, too, so I didn't have to pay attention much, and the miles flew by faster than they usually do. I have to fool with the magnet on the crank so the cadence reads out (it doesn't right now). And I have the seatpost extended past its limit, which isn't a great idea, but that's not such a big deal on a trainer.

Unfortunately, after a few rides without any knee ache, today's ride left my left knee sore. So I'm going to get it checked out, and if I need to get it scoped, I can hopefully get that done and healed before the season starts.

All for now,


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