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Mangled Rim(6 posts)

Mangled RimJakob
Jun 25, 2002 11:05 AM
So, this has only a little to do with cross, but I thought one of you might have experienced something like this.

I bought some road tires to throw on my extra set of cross wheels. I've raced on these wheels the last two years. The rims are some older Velocity's that were new when I got them. The tires are Ritchey Tom Max Pro that I scored from Nashbar for $15/piece.

Last night I installed the rear tire and started working on the front when _BAM!!_, the rear tube blows. In the process of removing the tire, I noticed there are two huge blowout areas in the rim! The sidewall of the rim has moved about 1/4 inch out from where it used to be. The rims had been totally rideable prior to the tire installation. Now, with the blow out section, the thing hits the brakes and immediately stops, which tells me the tube popping must have caused the blowout. But, in feeling the rim, it seems that the bead is slightly less in the two spots with the blowouts. I had pumped the tires up to 105-100psi and 115 is there recommended max. The blowout also slightly tore the top layer of casing on the (brand new) tire.

Have any of you ever heard of this happening before? What caused it? The rim? Tube? Tire? PSI? All of the above. Man, this was weird!
re: Mangled RimJames A
Jun 25, 2002 1:25 PM
I saw this on a MTB with Velocity deep V rims. I think what happens is that the rim gets thin from brake pad wear and eventually the pressure of the tire/tube blows out the rim. Downright scary event. Velocity rims (deep v's) are notorious for doing this because they are a little thin in the brake shoe path.

I still like the rims though - - I have a set on my Redline and I would not change them - -- a little heavy, but very stiff.
Jun 25, 2002 2:06 PM
I am so glad this happened in my garage and not on a descent or while on a long ride. Back to nothing but Mavics for me. I'm completely afraid to ride the front one now.

Thanks for the info, but are you sure you want to keep riding them?
jeezus indeedlonefrontranger
Jun 25, 2002 2:27 PM
I don't believe this is a specific problem to a specific rim, although I have also heard that older model Velocitys tended to be kinda thin (they tended to have weld quality issues too but I won't get into that). This is merely a possible result of letting your rimwalls get old and thin from neglect and gritty riding.

I had an older Mavic rim do this to me once in an MTB race; this was back in '96 or '97 when 1.5" semi-slicks pumped up to 60-65 psi was the going gig on dry singletrack. Fortunately it was the rear and I just skidded to a stop with the shredded tube and tire wrapped around my stays. Spooked the livin' **** outa me. Having that noise occur right in your ear is NOT one of the finer moments of trail riding, lemme tell you...

I changed that front rim out the very next day.
Jun 25, 2002 2:36 PM
...because i have a lot more miles on the front because i had to rebuild and eventually replace the rear hub on that wheelset. that rear rim maybe has a 1000 miles on it but it is an early velocity.
re: Mangled RimHENRY K
Jul 4, 2002 7:40 PM
Had the exact same thing happen to me last year on my Klein mountain bike. Scared the s--- out of me since it also happened in my garage right next to my face. I also chalked it up to the rims gettingb thin from the brakes.