rsacilotto

I have a Mavic OpenPro rim from around 2000 that has a dent in one spot. The dent predated my ownership, so I don't know how it happened. It's about 1mm deep by a half-inch wide. How should I go about fixing it? The only trouble with the rim is during braking - the rim is in front, so I get a decent shudder. How should I go about fixing it? If it's not fixable, I will replace it, so I'm not worried about making it worse.

Thanks!

Bill Kapaun

If you have an anvil, block of wood & hammer, you should be able to make it "less disgusting".

fietsbob

perhaps .. depending on tools and skills available.. But, shuddering may not be cured
just by banging out that dent.

cyccommute 

Short term: Maybe.

Long term: No.

You can bend aluminum but it doesn't really like it much. In all likelihood, the rim will crack when you try to bend it back. And it will certainly have a weak spot there. If you had to straighten it for a ride out of the woods, it would be okay but otherwise, just replace it. Wheels are pretty cheap.

GeorgeLeslie

In 200 when I purcharsed my mail order bride....err mail order bike , It arrived with a damged rim. It seem UPS stacked something heavy on it and it left a dent resembling yours. Bottom line, I replaced the rim and had the wheel rebuilt. I was able to carefully move the dented section with a pair of pliars wraped in a cloth. It looks like nothing ever happened to it. I now have a spare rim ready for a new assembly.

FBinNY 

The grades or aluminum are fairly malleable, but not overly so. It will tolerate rebending or hammering to shape, but you want to to it with a minimum of working of the metal.

Before starting, analyze the nature of the dent. Is it in or out on the sides? How far? How does does tire sit on the rim, and does the tire run true enough that you don't feel it when riding?

Then I approach these by using an old and dull chisel standing in a vise as an anvil to support the rim by the inside lip, or using a pair of pump pliers (like Channeloks) and wood to bend one side, while ensuring that the good side is undamaged.

Depending on the details of the problem, and your hand skill, this rim can possibly be restored to about 90% of as new condition, and can serve well for years.

BTW- you can rarely form the rim perfectly enough for the brake to run perfectly smoothly, but if you leave the bump slightly to the outside, it can be dressed very smooth with a file, and the normal wear will have it braking perfectly smoothly in short order.

cny-bikeman

Nobody can tell you if it can be fixed ahead of time. It potentially can, and you'll know once a proper attempt has been made and you know whether it has cracked. I personally use a piece of hardwood and a dead blow hammer, with the rim laying flat on a softer piece of wood.

Looigi

Basically the same as I've done and had good luck with. However, I find using a press rather than a hammer easier to control and easier to get more perfect results.

berner

I have a rim that had a similar bend which I fixed. As FBinNY said, aluminum can be bent but it's not that happy about it. I bent it back a tiny bit over much and used a file and hard sanding block to get level, per FB's instructions.

dbg

I don't like that exposed metal piece sticking out from the rim tape. Might compromise the tube when inflated. I'd put new, larger rim tape on that bad boy. (Actually I'd toss the rim)

Grand Bois

Bend it back it's not going to crack.

FBinNY 

And even if it does, your're no worse off than if you decided to chuck it without trying.

likebike23

I used an adjustable wrench on a bent rim. The jaws are smooth and won't roughen the rim bead like channel locks.

achoo

Tell me about it. I dinged a rim a few months ago, bent it back, did everything right - can't even find a difference with calipers.

And it STILL shudders when braking.

Gave up and just replaced it last weekend.

rsacilotto

I got it pretty close, using FB's technique except instead of a chisel (only wood chisels on the bench), I used a large flat screwdriver. I tapped the outside gently with a hammer until reasonably flat, then sanded the surface with a palm sander, and finished with a wood block. Hopefully the braking action will be better. Thanks, everyone, for the advice!

hueyhoolihan

IME, functionally, braking issues aside, fixing a dented has worked for me.

i've on occasion swapped rims so that the damaged rim is on the wheel that is little used for braking, but i've eventually replaced the rim anyway even though it is still round and the braking surface has plenty of metal left on it...

good job! i'll be sincerely interested to hear how well you are satisfied with the braking.

FBinNY 

That's just the side of a double eyelet. The tape apparently isn't right down the middle.

rsacilotto

As predicted by contributors to this thread, braking is not perfect, but it is dramatically improved. Imperfections are very hard to identify by eye. I'm thinking of using vinyl spackle and a putty knife to show the remaining dips, it may allow for correction. If the issue is a bump, I can do some more sanding. In any case the possibility of saving $300 is motivation for another hour tweaking the rim in the garage. :-)

FBinNY 

To save you some wasted effort. You cannot fill dips on the braking surface. The action of the brake shoes on a moving rim will rapidly dislodge any fill and fling it off. depending on the depth your best option is to disregard and allow normal wear blend it in, or to push it closet to the correct height, then file off excess. As I posted earlier, perfection isn't a goal, normal wear will give that to you. You just want to get to "good enough".

It's very easy to sacrifice a good job on the later of perfection, so your guiding principle has to be "quit while you're ahead"

rsacilotto

FB, I said it poorly, the purpose of the spackle is to expose where a correction is needed, not to fill the gap. I would remove the spackle and then focus on tweaking exactly that spot. Just a theory, have no idea if it will work.

FBinNY 

Color the suspect with a dry marker, then go for a short ride with a few brake applications. High spots will clean off first, low spots will stay balck a bit longer.

Bill Kapaun

+1

Grand Bois

You didn't say it poorly. I understood you.

a77impala

+1

Kimmo 

Looks like a decent fix.

I've always had good results using nothing but an adjustable wrench and lots of care and patience.

The trick with stuff like this is to make sure you stare at it long enough before making a move.