Tuesday, April 13, 2010
IBC finally got some Bontrager Team Issue 29-3's in. I've been wanting to run these on my new Gary Fisher Superfly. In the interim, when nobody local had these tires in stock, I went with some Hutchinson Toro tubeless ready tires. They are great all-mountain tires but not race worthy tires for dry or hardpack conditions. They are quite slow on pavement. The Hutchinson's went on the rim quite firmly, and I was able to inflate them just as easily as tubed tires with a hand pump. In fact, I ran the rear tire at 19psi through the gnarly Burlingame TT course with nary a burp. That rim bead design combined with the Stan's Arch rims has my complete confidence.
The Bontrager label claims these team issue tires weigh 600g. In the hand, they felt heavier than that. So I put them on the one tool every serious rider has in their basement, the gram scale. Sure enough, one tire weighed in at 725g, the other at 740g. That's 23% over the claimed weight. I could see 5-10%, but 23%? I thought I'd be saving half a pound over the Hutchinson's, but this was a wash.
So tonight I got around to mounting my new 29-3's. The first tire went on the rim way too easily. That right there gave me pause for concern. How secure will this bead seal be when running low psi over typical New England gnar? I tried to inflate the tire with hand pump. No matter how I fussed, the air escaped as if there were no tire on the rim at all.
So I go to the compressor. Even that took some doing to get initial rim seal. My procedure is to put a few pounds in, inspect the bead for even seating, then inflate the tire past normal riding pressure to firmly seat both beads around the tire. The tire is rated to 50psi. I put in about 45psi. I was grasping the tire in my left hand, ready to lift it to my face for further inspection, when the entire bead blew off the rim. W.T.F! My hand went completely numb and both ears were ringing fiercely. I couldn't even move my fingers, they stung so badly. Stan's sealant covered a quarter of the basement - floor, walls, equipment, even the ceiling.
I did remount the tire, careful to not go above 30psi. Racing pressure would probably be around 25psi I think. My concern is that the bead is too "stretchy" to hold tight around rim. I hope to get out for a test ride on these tires Thursday. I haven't decided yet if I will race my 29" Superfly or 26" Racer-X on Sunday. I haven't had a trail or race mishap due to tires in a long time now. I hope the Bontrager's don't let me down.
Currently, my favorite tubeless racing and all around riding tire is the WTB Mutanoraptor. They don't last very long, but they roll fast and the low profile sticky rubber knobbies grip everything. I've been riding and racing these for many years and have yet to have a mishap with them. They are getting hard to find now and are not available in 29". I keep trying other tires. I have a whole wall full of barely used tires, a collection that could rival the shoe collection Imelda Marcos amassed. At least Imelda Marcos liked her shoe collection. I hate my tire collection. Every time I see it I think about how much money is tied up in them. Time to have an Ebay clearance sale.