How To Repair A Bent Bicycle Rim

"Ksh ksh ksh" goes your wheel as your ride. This is the sound of a bent rim. Here's how to fix it.

Past Dan Goldwater

"Ksh ksh ksh" goes your bike equally your ride. This is the sound of a bent rim. Aptitude rims are frustrating because they slow yous downwardly, but they are usually like shooting fish in a barrel to set up if y'all know how.

Rims can get bent out of shape from hitting a big pothole, by getting twisted when you endeavor to wedge your wheel in or out of a rack and when a spoke breaks. When the curve in the rim is big enough, it volition hit your brake pad every time it goes around, causing the characteristic "thwp" or "ksh" sound, and slowing you lot down.

Fixing a moderately bent rim yourself is easily accomplished with a spoke wrench, which comes in several sizes. Most multi-tools will take two to four sizes of spoke wrench to fit the different sizes of spokes available on the market. Pro mechanics remove a bent wheel from the bike and put information technology on a special truing stand, merely this is non needed unless you desire to go a racing wheel in tip-top shape. For a regular bike, you can true it quite nicely without even removing your wheel from your bike.

Checking the rim and spokes

Flip over your bike so you can spin the bicycle easily. First check if you have any broken spokes. If and so, you tin can follow the same process to straighten out your rim, but you volition desire to become that spoke replaced soon. Lighten the load on your bike equally much equally possible if you take a long way to go with a broken spoke. Next, check that your axle is fully seated in your dropouts. If you accept a quick-release wheel, information technology might not exist. You lot don't want to re-true the rim if the merely problem is that the axle is non sitting directly. Same thing with your brakes – first bank check that they didn't get bashed to the side or the brake cablevision isn't hung up on something.

Checking the alignment

Slowly rotate your wheel while you look at the size of the gap between information technology and your brake pad. As the wheel turns, yous will notice that in some places it is closer to the pad and in some places farther away. With a perfectly truthful wheel, the gap will exist fifty-fifty all around. You don't need it to be perfect.

Finding the problem spots

Slowly rotate to the part of the rim where it is hitting the restriction pad. Here my rim is bent to the left. To fix information technology, I tighten the spoke reverse the bend: the spoke circled in dark-green. Tightening this spoke pulls the rim to the correct. If the curve was going in the opposite direction, I'd instead tighten the spoke circled in blueish.

Tightening spokes

To tighten a spoke, place the spoke nipple into the notch in the wrench. Check that yous have the correct size of wrench. Plough COUNTERCLOCKWISE to TIGHTEN. If you have whatsoever doubt, kickoff "pluck" the spoke like a guitar string to make a audio. Tighten i total turn and pluck once more. If the pitch is higher you are tightening the spoke; if information technology's lower, you are loosening it.

Getting information technology truthful

The ding in your rim might be a couple of inches long. Start by evenly tightening the two spokes opposite the ding by a one-half turn of the spoke wrench. And then recheck the gap. Echo until the ding is mostly straightened out. If you have a larger dinged expanse, you might stop up tightening three or four spokes contrary to it. If the nipples are corroded, put a drop of oil on them so they are easier to turn.

Finishing upward

Afterwards the bicycle spins freely and the gap looks reasonably even all effectually, become effectually the rim squeezing each pair of spokes. This will even out any stresses in the rim. Recheck your truing after this.

Tips

You can also loosen the spokes contrary the ones you are tightening, which is particularly helpful if y'all would otherwise need to tighten by a lot of turns in one expanse.
If your rim has several dings in various directions, offset with the largest i.
A less common, but fixable problem: yous might go an area where the rim is farther away from the hub than the other areas. This can be improved by tightening all the spokes in that area evenly.
Pluck spokes to judge their relative tightness.
If you have to tighten past more than than 5 turns of the spoke wrench, your wheel is probably in bad shape. Rims tin can get too damaged to be re-trued – subsequently plenty dings, you'll need a new one.

Desire more?

You can find this article with extra photos at: instructables.com/group/momentum

Dan develops bike accessories with MonkeyLectric. Previously, he co-founded instructables.com, was a scientist at MIT and developed microchips at Intel.

dan@monkeylectric.com

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