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Trahsed Rim?(7 posts)

Trahsed Rim?mgolebiewski
Oct 8, 2002 10:37 AM
I had a bad blowout last night. Somehow I ran over a screw. The screw when through the tire/tube, and into the inner layer of the rim. The end result is that alongside the holes to access the spoke nipple heads I have a new hole left by the screw. The screw stopped in the hollow layer between the inside and outside of the rim.

My question is about the stability of the rim. My gut feel says it is trashed. However, looking at the damage it put a new hole where the rim is already drilled. The hole is pretty well centered. From a structural point of view I can't see why it would weaken the rim. However, this does not match my gut feel.

Anyone else have this happen? Is the rim still safe to ride or am I out some money for a new rim?
I wouldn't trust the rim!johnnybegood
Oct 8, 2002 1:46 PM
Wierd! I wouldn't trust the rim. Even though there is likely significant cost to rebuild the wheel, you can salvage the hub and have a new wheel built and not worry when you ride(check out Colorado Cyclist wheel rebuild costs!). From a structural standpoint, the existing spoke holes are perfectly round. Some model rims even include a grommet to distribute the force from the spoke to the rim more evenly. A round hole will distribute stress equally in all directions. If the screw hole is not perfectly round, stress will be channeled in one direction, and likely induce a crack. In addition, the force of pushing the screw through the rim induced stress and could already have started a crack. I don't think the rim would catastrophically fail, but the damage is in a place where you can visually check it without removing the tire and the rim strip. If a crack did propogate, an inner tube blowout is possible. An instantaneous blowout while descending at high speed or while leaned over in a turn could be just as catostrophic as a rim failure.
keep itJofa
Oct 8, 2002 2:34 PM
Obviously, make sure that there aren't any sharp corners that would cause a puncture, filing away the edges if necessary.Apart from this, your rim will be fine. Rims work solely in compression: it could be made out of 32 (or however many spokes you have) seperate pieces, all abutting one another, and only behave differently in the case of a dramatic accident (like riding off a high wall), in which case it would explode, rather than fold into a saddle shape. If your rim failed in this way, it would go at the join first, before your new hole. Either way, you'll live.

Jofa
keep it and use it on trainer\rollers...n.m.koala
Oct 8, 2002 5:32 PM
Don't sweat it.Matno
Oct 9, 2002 2:07 AM
Doesn't sound like it's bad at all. Just check it out every couple of weeks for a month or two to see if anything develops. If not, forget about it and ride.
If you think about it.......Dave Hickey
Oct 9, 2002 2:46 AM
Manufacturers don't beef up the area around valve stem hole. How is this any different? If it's in the center of the rim, I don't see any problems.
Relevant experienceKerry Irons
Oct 9, 2002 5:27 PM
A riding buddy had nearly the same thing happen two years ago. New tire, new tube, new rim strip, same old rim. Two years gone by and no problems. Not an issue.