Friday, October 02, 2015

Another "Valley of Death" rim

This is a Bontrager AT550 hybrid rim, 622X20 mm. It has the troublesome Valley of Death, where inner tubes meet a premature end. The skinny rubber rim strip can slip aside, uncovering a tiny fang on a spoke nipple. The inflated tube distends down into that deep channel, stretching unevenly. Sometimes tubes fail just from that. In other cases, the thinned part in the channel is more vulnerable to chafe.

Throw in the life line!

Ordinary clothesline fills the ditch. You have to allow for the valve hole.

Then top it with rim tape.
This cumbersome process brought to you by The Bike Industry and the fine re-labelers at Trek.


Steve A said...

Do you use special "ultralight cycling" clothesline that is carbon impregnated or just "regular" clothesline? 😜

cafiend said...

I can't afford anything fancy.

Justine Valinotti said...

Now I'm really upset that Bontrager is just another Trek brand. When he was working independently, Keith Bontrager designed and made abikes and parts that made sense (I know: I rode one of his bikes for a few years!) But now it seems that Trek will just stick his name on anything.

I guess when Trek bought him out, he signed away any veto power.

John said...


cafiend said...

Justine -- The thing about Bontrager stuff even when it was his, is that it made sense, but not really any more sense than a lot of other stuff out there. I could never figure out his reputation as a genius. He wrote a thing about riding position that was presented as controversial, but really turned out to be a specious spin that did not really overturn traditional methods. His bikes were nice enough, but not jaw-droppingly brilliant. A lot of stature in the 1990s was gained on personality more than actual ground-breaking work. Many "innovations" of the period owed more than they realized -- or more than they admitted -- to concepts dating back to the 1890s.

John -- Thanks!

Justine Valinotti said...

Cafiend--I agree that his reputation was overblown: he didn't do anything ground-breaking. On the other hand, I never had any trouble with his pre-Trek stuff, and I really liked the ride of the bike, which he built in California.