jroth

I dinged my rear rim last weekend. There's a definite hop in the wheel. I can hear it when I brake and feel it in the brake lever.

I can feel a slight bulge in the rim and the spoke there is loose. I put the wheel in the stand, but can't true it.

Continue to ride? Tighten the spoke a bit? New wheel?

Thanks.

Joel

cyccommute 

If you've got loose spokes, you've blipped the rim pretty hard. You need a new rim. If you can get the same rim or a rim with the same effective rim diameter (ERD), swapping the spokes to a new rim isn't that hard. You'll need to detension the wheel, tape the new rim to the old rim and then move the spokes one at a time to the new rim. Then true, tension and dish. This is the prefect way to learn the harder parts of wheel building, which is the true and tensioning.

FBinNY 

With respect I disagree with the pessimistic analysis above.

It's a matter of degree, but many dented rams are highly salvageable, and can be made just about as good as new. Or at least good enough that the dent can't be felt riding, and the wheel can last for years. Just about everyone who rides daily on the lousy pavements of major northeastern cities has had to save a dinged rim.

First of all, assess the extent of the damage by riding it and seeing if you can feel the hop. Often you won't, because the tire can still be round even on a dented rim. Even if the den is severe enough that you can feel it, all isn't lost, but skill is required to fix it.

As for the blip in the brake track, that can be gently squeezed back, then filed or sanded back into line. Once it have it very close, the normal brake wear will make it perfect in short order. There's even a tool made specifically to fix rim blips, but you don't need it and can use either a hammer, or pliers and wood.

If you're bringing it to a shop, be aware that who you bring it to will make a bigger difference than the extent of the damage. Urban mechanics are used to doing this kind of work, where as some high end shops in the burbs may feel it's beneath them.

cny-bikeman

I'm in between the above posts. Yes, often a ding and flat spot can be fixed, but it does take skill, and specifically more than just truing. The rim MUST be pushed/pulled back out again if the wheel is to be round and stable, because if you tighten the spokes at the flat spot you will increase it; if you don't the wheel will be weak. You need a good touch. Google "bike wheel flat spot" for ideas. I am partial to using a 24oz plastic faced dead-blow hammer to "nudge" the rim out, but have also put the wheel on a storage hook and pulled.

SBinNYC

There are also tools to remove dents from rims.

dsbrantjr

SB: A link to a source of the tool would be appreciated, I am sure.

TallRider

just to be clear, the tool that FBinNY linked is for removal of side-to-side blips, and the tool linked by SBinNYC is for removing vertical hops. You NY guys have it covered.
However, for at-home repair of a single wheel, I'm not sure it's worth buying either tool. Try with a hammer (preferably a rubberized mallet) and/or pliers, as FB suggested.

fietsbob

No special tools?
Newtonian Brutality .. a horizontal beam that sticks out, that you can get thru the spokes.

slam the wheel down over it from the inside out. [maybe loosen spokes a bit there, 1st]

width blip. lay rim on workbench, hit blip , via piece of wood, with your hammer ..

or the big watermelon smashing mallet.

FixedDriveJess

New wheel, definitely. Alluminum (im assuming your rim is allumium) will continue to crack and all the sudden you'll hit a small bump and you're entire rear wheel will collapse.

FBinNY 

The OP hasn't mentioned any cracks, so assumes something not in evidence. The aluminum used in rims is moderately ductile and will tolerate a certain amount of cold working (not repeated back and forth efforts) and saving rims with this kind of damage is a time proven mechanical exercise.

Like most of wheel alignment and repair, the amount of skill involved depends on the extent of the problem, but most, if not all, minor blips are fairly easily corrected.

For home repair, neither special tool is needed. The low spot can be pushed out with a foot, and the blip in the brake track squeezed in with a pair of pump pliers, using a flat piece of steel or wood to spread the load on the opposite side. If one looks at the picture of the tool I referenced earlier, he'll get the idea.

onespeedbiker

I had the same issue with a Mavic MA2 and this is what I did. De-tension the spokes and put it on a truing stand. Find the hop and remove three or four spokes in the area of the hop. Place the wheel, with the hop down, on a firm cushion (I used a chair). Now take a rubber mallet and bang on the hop until you have rounded it out;depending on the tire and pressure, a millimeter off one way or the other will probably not be felt. As far as sidewall if it is bulging find a piece of wood, or better hard plastic the width of the ID of the rim and place it where the bulge is under the bead hook, and tap with a ball peen hammer to remove the bulge. If the sidewalls are simply flared out then use a smooth jaw channel lock pliers to squeeze it back into place. You will not remove the regularities entirely but again you can mitigate them. .

FMB42

Have you priced a replacement rim from the manufacturer and/or your local bicycle shop? A factory replacement or a suitable after market rim might allow you to re-use most, if not all, of your existing spokes (just keep in mind that one, or more, spokes may have been over-stressed/damaged when the rim was dinged). The reason I ask is that name brand "after market" 26" and 700C rims start out at about $40 USD. I could, depending on the severity of the ding, see trying to straighten it out just to get you by for a few days (if you have no other form of transportation). Another "straighten the rim" scenario would be if this was your beater bike that you don't run too fast or hard. However, imo it would be best to replace it as soon as possible rather to see you have problems with it down the road.

byte_speed

Do you recommend taking it back to a bare rim for this procedure or can you just remove a few spokes?

otg 

I had this problem with an old rim a few weeks back. I took it to a bike shop in the city thinking I needed a new rim. The two mechanics checked it out closely and told me they could repair it, and it would be just as strong as new. 20 bucks later, good as new. They easily could have sold me a new rim, so they have earned a customer even though it is a 45 minute drive from my house. It was in Providence, a city with a ton of students, so they probably repair a lot of bikes for students with little cash to spare.

FBinNY 

You don't remove any spokes, but need to loosen spokes in the limited area you want to move to the last thread. It's surprisingly easy (except on deep aero rims) to push it out too far, so leaving the nipples on acts as a safety.

FixedDriveJess

The way I see it- you have a 1/100,000 chance of the wheel suddenly collapsing. When it's alredy cracked.. I'd say knock a zero off for every 50 miles you ride.

FBinNY 

As someone who's dented and fixed rims routinely for 40+ years, I assure you that if the ding is minor, and the repair well done, the rims life will be like new.

It might even be longer because of Murphy's Law. Many decades ago I must have insulted a witch because for a span of almost 20 years, I couldn't keep a newly built wheel perfect for more than a few weeks. Every time I built a new wheel I'd find a rain filled pothole at night, and dent it. I couldn't afford to keep building, so all my wheels have seen the hammer and file.

Now ,once you have a dented rim your attitude changes. The wheel has already been Baptized, and you're mentally less invested. You might even buy a spare rim to have it ready for when the time comes. But the minute you don't care, especially if the wheel is not quite perfect, and you kinda wish it'll give you a reason to start fresh, Murphy's Law kicks in, and that's the wheel that you'll be riding for eons.

onespeedbiker

LOL! There is some real truth in your comments here.