h2o_polo_boi

Got into an accident yesterday and bent my front wheel. The rim is slightly bent in various places but spokes and hub are fine. However, in my limited experience in truing wheels, I do not think the wheel can be fixed through conventional spoke tensioning. Any ideas on how to fix it?

As a way of gaining knowledge and experience, I decided to fix my wheel. I was thinking of taking out the spokes and hub, leaving the rim, and flattening the rim with weights and a big piece of board. Then I would rebuild the wheel using the same spokes and hub. I have all the tools needed to build a wheel (truing stand, tension meter, spoke wrench).

So my question is really will it work? If so, do I need to remove the rim strips?

operator

You need:

1) new spokes
2) new rim

moxfyre

I *have* heard of people successfully straightening bent rims, but not by more than 1 inch or so. And I'm not sure how long-lasting the results are. It may be quite difficult to get the wheel evenly tensioned and trued after doing this!

operator's advice of new rim is probably the easiest solution by far! It's commonly believed that spokes should not be reused, but Jobst Brandt (author of "The Bicycle Wheel") says that it's fine and perhaps even preferable to reuse spokes, EVEN when the wheel had been bent!!! Read this: https://yarchive.net/bike/spoke_reuse.html

h2o_polo_boi

Is there any reason as to why I would not be able to salvage the original rim and spokes?

An edge of the rim was bent inward, and using an adjustable wrench, I bent it back within 4 seconds. Now you can't even notice it. I'm wondering, if it was that easy to bend the wall back, why would i not be able to squash the rest of the rim back into true and then rebuild it?

btw, my front wheel has 20 spokes if that helps.

moxfyre

Aluminum does not take bending well. If it is JUST the edge of the rim that needs to be bent back in place, that's probably okay, but if the overall shape has been distorted, it's not so good. It's quite difficult to bend a rim back into shape, for one thing. Your idea of pressing it between two heavy, flat surfaces probably won't work because you have to bend metal PAST the desired position in order to permanently yield it. (For example, if you bend a paper clip by 1 inch, it might spring back by 1/4 inch.)

Also, after all this bending, the rim is likely to be weaker around the bends. Might cause it to sag or bulge or come out of true more easily. How far out of round/true is it anyway???

h2o_polo_boi

Those are good points. How do you find out how far out of true? All i know is it scrapes against my dual-pivot caliper brakes even after they're released. Definitely more out of true than my fully-released brakes. Probably "un-savable" huh?

moxfyre

Iffy! Do you have a truing stand? You're surely gonna need one for this job... I'd say *roughly* that if it's more than 1 cm out of true laterally, or if it has a bad vertical hop or dip, junk the rim. Also, make sure that you don't have a BROKEN spoke. If there's a broken spoke the wheel can be quite out of true without any permanent bending of the rim.

Retro Grouch 

1. I doubt you are going to be able to rebuild a bent 20 spoke rim satisfactorily.
2. What do you have to lose by trying?

Here's two methods that might work depending on what kind of bend the rim has:
1. If your rim is warped symmetrically and looks kind of like a potato chip, try bending it back over the side of a bath tub. Check it against a flat wall to see if you've gotten it straight.
2. If your rim has an asymmetrical bend - just one part seems bent, find a big, heavy chest of drawers. stick the rim into a drawer up to the place where the bend starts and see if you can lever it back.

Uh - I received no money nor any other consideration for providing this advice and I assume no liability. If you try doing this, you're entirely on your own.

h2o_polo_boi

the wheel is only laterally out of true. not sure how much out of true but i got some pics...

part that is true


part that is farthest to right


part that is farthest to left


What do you guys think? Fixable?

Retro Grouch 

Seems like a pretty nice bike to be thinking about jacking around with the front wheel. If it was my bike I think that I'd just order up a new rim and spokes and be done with it. I don't think that a 20 spoke wheel is the right one to attempt your first wheelbuild either.

h2o_polo_boi

Yeah, I see your point about getting new rims and spokes. But like you said before, what do I have to lose? If I can fix it, then I would have learned something and not shell out more money then I already spent. If I can't fix it, oh well, I still would have learned something about wheels.

Either way, do you guys think it can be fixed into a satisfactory condition?

Al1943

Yes, I think you can fix that one, can't tell for sure from the picture. I've fixed a couple of rims that looked worse than that one. I use blocks of wood on my garage floor and press against the concave side of the rim (all spokes removed). I had to stand on one rim. I've heard of mechanics on road tours slamming wheels against oak trees to straighten tacoed wheels.
After you get it back together your tension meter will tell you if it's straight enough. All of the spokes should have tension within 10% of each other, I would shoot for 5%.

Al

operator

Then seriously, stop asking and do it. And if it fails or it works come back and tell us about it. What have you got to lose?

Sounds like a load of bull to me if you are indeed using the term 'tacoed' correctly. A folded rim like that being bent back into usable shape? My skepticism meter is flying off the scale.

Al1943

It was done for a friend of mine. I didn't know "tacoed" was that well defined. I'm sure it wasn't folded over.

I_bRAD

I think you can fix that. I wouldn't remove the spokes though, I'd bend it back as close as possible (the edge of a bathtub will be just fine, the edge of a workbench with a rag for padding will do as well without offending other bathtub users.) Once you get it close then true it.

h2o_polo_boi

Fair enough. Quick question though. Will I have to remove the rim strip to take out the spokes? The reason I ask is because the rim strip is glued to the rim and I don't really want to undo it.

operator

Yes. You can use a hair dryer to heat it up a bit and it should come off easily. Get non-adhesive rimtape - ($3 will buy you 2 rolls of the the best rim tape).

waterrockets 

You can reuse the spokes, and should.

h2o_polo_boi

Cool. Which rim tape would that be?

Al1943

It's hard to beat Velox rim tape. It has a sticky back but can be reused several times without any mess, just try to keep it clean.
Be sure to get the spokes back in the same way they come out. Take pictures and make notes as needed.

twowheelfunman

My first mountain bike came from Target circa 1986? I took it out to some dirt hills, caught small air and landed with the front wheel turned a bit. After dusting myself off from going over the bars I discovered a SEVERLY tacoed wheel. Not folded over but WAY tweaked. All I could come up with was jumping on it & amazingly it POPPED back into rideable shape. I don't remember if I had to replace the wheel/rim/bike but I upgraded pretty quickly.

DannoXYZ 

Hard to tell from the picture if the wheel was taco'd or simply untrue. A taco'd rim takes on a toroidal shape and truing it back into shape results in S-bends and areas with spokes being wildly different tensions on each side, then reversing a little later. You can repair it if you can reverse-bend it in the opposite taco shape.

Even better is to bend the rim after it's been disassembled. You can see the taco shape by unlacing the wheel completely. It may be possible to bend the rim back by using the edge of a table or bathtub so that it's flat and no longer taco shaped (use a glass table as a measuring tool to check for flatness). Then re-lace the wheel. However, a lot of repaired taco'd rims still have residual weaknesses (microscopic cracks) that shows up when tension is applied and the rim takes on that taco shape again.

In this particular case, if you can true the wheel back straight without wide variations in spoke tension from side-to-side, then it should be OK. Fine to re-use spokes, I've done it plenty of times. Spokes fail from fatigue with many on-off cycles through wide ranges of tension. An impact actually reduces tension on most of the spokes as the wheel tacos, so only the spokes that have actually been hit laterally will be damaged. These are the bent ones, replace those, the ohters are fine.

Easy way to replace the rim is to just tape the new one right next to the old one. Make sure the spoke-hole orientation is aimed correctly. Then just unscrew the nipples and transfer one spoke over at a time and use a new nipple. Shouldn't take more than 10-15 minutes with that wheel.

BikeWise1

If the wheel can be made "straight" but the spoke tension is all over the map, the rim is dead.

People need to understand that straight and true are two different things.

A straight but not equilibrated wheel is not true. The lack of even spoke tension precludes this.

A true wheel will remain straight until something acts upon it and causes it to be out of true. Guess what? Out of true wheels can be straight-they just won't stay that way.

20 spoke wheels are high performance items. What you save by going cheap here may be lost when it comes time for reconstructive facial surgery.