Take the 2-minute tour ×
Bicycles Stack Exchange is a question and answer site for people who build and repair bicycles, people who train cycling, or commute on bicycles. It's 100% free, no registration required.

I found a dent on my rear wheel on the weekend, a UST rim which I had been running a UST tyre on. This was allowing the tyre to burp (not running sealant) so I had to repair or replace. It was the first dent on this wheel and only relatively small (size of nail on small finger)

Using the technique of holding a flat piece of metal aginst the rim and carefully working along with a adjustable spanner I managed to get the rim straight without any further damage and could not see any cracks. The bead seems to have maintained it's shape.

I refitted the tyre (finally perfected the technique of seating a UST tyre with a floor pump) and it held pressure overnight although I've yet to ride on it.

Are there any possible issues that I should be wary before riding this wheel? Should I be confident that there is unlikely to be a catastrophic failue?

I'm not concerned about burping, I can manage that just worried of a rim breaking at speed downhill.

share|improve this question
    
Aluminum "work hardens", meaning that it gets brittle when bent (much more so than steel and most other metals). The rim has been permanently damaged -- made more subject to fracture -- but it's hard to say how badly -- depends on the specific aluminum alloy, the degree of the bend, and how much you "worked" it while straightening it out. –  Daniel R Hicks Nov 17 '13 at 23:16
    
Thanks Daniel I thought as much. The dent was too bad, probably no more than 3mm inwards over about 10mm of the rim. I was very careful working it, using small movements and making sure it couldn't over bend. –  DWGKNZ Nov 17 '13 at 23:32
add comment

2 Answers

up vote 1 down vote accepted

Are there any possible issues that I should be wary before riding this wheel?

No. Just go ride. Always have a spare tube with you.

Should I be confident that there is unlikely to be a catastrophic failue?

The only catastrophic failure I see is if you hit the rim (e.g pinch flat very hard) again on the exact same spot. Then there is a high possibility that the aluminium will crack.

Don't worry too much. If you've pulled the rim dent back at 95% of the correct position then you have nothing to fear of. My rear wheel on my old bike had 9 (nine) of those straightened dents and I was using the ghetto tubeless method. No problems whatsoever. Here is a similar dent on my new bike just before fixing it: http://i.imgur.com/oMGab6L.jpg

share|improve this answer
    
UST rims are normally run tubeless, though they can run tubes (if you're going to do that though, you're pretty much defeating the point of shelling out for the UST rims). I'd think the failure mode would be highly dependent on the amount of dent and how it was bent back though. I don't have much experience with tubeless rims, so I don't have anything more useful to say. –  Batman Nov 18 '13 at 6:04
    
Of course they normally run tubeless. What I meant is that he should always carry a spare tube with him so if the wheel fails 20km away from home/car/pickup then he can fix it and return safely. –  cherouvim Nov 18 '13 at 6:09
add comment

Basically you've compromised the integrity of the rim. Now, the real question is how much you've compromised it? I would say this depends on the type and material of the rim. XC rims can only take so much abuse before needing replacements, where as big, burly downhill rims can handle a lot of dents, strikes, etc.

After only one dent, I wouldn't worry too much about any rim, unless you completely caved in one side of the rim. If it's bad enough that you're constantly burping you should consider replacing it. There's the matter of comfort as well, if you flatten out a section of rim, you might feel it on every revolution; that's ridable, but probably not too fun.

Also, and this is personal advice, I've found that my rear wheel takes much more abuse than the front, so you may get away with swapping your rims around (assuming similar hubs, spoke count, etc). Again, I didn't say this would guarantee no problems, but might help your rim last longer.

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.