Once a rim is bent, can it be straightened?

[Floont]

After my unfortunate accident yesterday, I bent both rims on the bike. (As well as breaking the front brake calipers off, and a lot of cosmetic and some electrical damage that I can repair).

The rear rim which is the original cheap single wall rim that came with the cheap bike. I want to replace it anyway and it's bent so bad it won't roll anymore, so that's not the issue.

The front rim which has an x5304 hub-motor is is a good double wall rim with thick spokes (can't remember the gauge). It now has a small wobble in it, but at least the rim is round. Is it possible for the good rim to be straightened? And how is that done? (I would attach a picture, but it's hard for me to move today after the accident).

FA

 

[LI-ghtcycle]

A lot can be done with a truing stand and a spoke wrench, however to make this judgment you really need detailed pictures for us. If you have a local shop you trust who builds wheels, take it in and get an opinion from them. I would say as long as there aren't and real deep dents or cracks (aluminum or steel rim?) it generally is salvageable.

 

[Drunkskunk]

Depends on the bend. A wheel can be so Taco'd it wouldn't even roll and be straightened if the bends are smooth. But the spokes are probbably shot. They have to be stretched out of shape to let the wheel bend.

 

[blkbikes]

If you want to learn about wheel repair check out Sheldon browns wheel building on the net.

You can use your frame and fork as a crude wheel tru'ing jig. Add some taped pens to use as guides.

My advise about your wheels is to consider getting your local bike shop to stick some nice tough rims on. I build wheels for a living and highly recommend wide downhill rims with a 2-2.25 tyre. The wider rim gives a lower tyre profile and allows higher pressures to resist punctures due to the increased weight.

Hope that helps

 

[dumbass]

I had a simular situation last year where an asshole pulled out of his driveway right into me. the bike and me were pretty beat up. The front wheel was bent bad enought that i had to completely remove the brake before i could ride it home. I took it over to an old guy in the area thar does bike repairs and he aligned it for 15 bucks. It had a least a 1/2" wobble side to side.

Bob

 

[dogman dan]

Yeah, it varies so do give straigtening it a try. Wobble can be fixed pretty easy usually, though as mentioned a strectched out spoke may break, or be too long now to work right, either running out of threads or poking holes in tubes. A goodly flat spot taking the rim out of round is a lot harder to fix, and may not be saveable.

The short explanation of wheel truing. Get something to rub on the rim, tape, a piece of wire, whatever works for you. Some just use the brake pads, but I find they move around a lot. Using the spoke wrench, tighen spokes and loosen the opposite adjacent one in pairs. loosen on the side where your wire touches the rim. Only a quarter turn on the spoke nipple at a time. Patience, take your time, keep going round and round getting it closer and closer. The doing it two opposite spokes at a time, loosening one and tightening the other takes out wobble, without putting egg shape into the rim. Once you have wobble pretty nice, start looking at the roundness. If when you are done, you end up with a straight rim, but some spokes real loose and others real tight, you may have a rim that should have been replaced. But can be ridden some temporarily till you get something better. Ride it some, and let it settle in, and then do one last bit of straightening. Then tighten up any really loose spokes at least enough to stop talking to you while you ride.

 

[spinningmagnets]

A 530X is a serious motor, how fast do you normally go? if an undiscernable stress-fracture develops and grows into a catastrophic split, are you OK with that, at the speeds you normally travel?

If it was a 20-mph bike, maybe it wouldn't be worth worrying about, but few people who invest in a 530X stay below 20-mph...

 

[John in CR]

I had a simular situation last year where an asshole pulled out of his driveway right into me. the bike and me were pretty beat up. The front wheel was bent bad enought that i had to completely remove the brake before i could ride it home. I took it over to an old guy in the area thar does bike repairs and he aligned it for 15 bucks. It had a least a 1/2" wobble side to side.

Bob

Hehehe, I pay less that $2 for truing. and less than $3 for the package deal of lacing a new rim, mounting the tire, truing, and adjusting the brake. Living in a developing country has some real advantages wrt bikes.

John

 

[Gregory]

I was told straightening a double wall rim is tough, harder than a single rim. And they are never the same again.
And you need to make sure the braking surface is spot on, because brakes are important.
My LBS wouldn't bother straightening mine, but maybe he just wanted to sell another rim?

Personally I'd toss it out and start again with new matching downhill rims.

Glad you can still walk (albeit slowly), get well soon.
Greg

 

[Floont]

.
Thanks for all the good comments!

After I got enough strength (and painkillers) to go out to the garage and inspect my wrecked bike further, I noticed that it wasn't just the front brake pads I ripped off, it was the entire brake assembly. I made a video of the out-of-true wheel for your professional opinions:
[youtube]MHYfXE_c2EU[/youtube]
No broken or loose spokes. What do you think??? Fixable? Or is it new wheel time?

Heres the rear wheel which I was going to replace anyway. It won't even rotate it's bent so bad:

FA

 

[amberwolf]

That front rim is right about as bad as my DayGlo Avenger's Fusin's rim was right after I skidded wrong on it. I fixed a lot of it by standing on the center of the outward-bent part, grabbing the rim on either side of my foot, and pulling hard upward, so I could at least ride it home.

I did more after I was given a spoke wrench to fit it (since I had lost the one I made for the purpose), and was even able to put the brakes back on it, though they still rubbed on one side every revolution; it wasn't hard enough to slow me down, just increase pad wear on that side. It still seriously needs either new spokes on that part of the rim (they're as tight as they can go and still not enough) or I need to unlace the wheel and clamp the thing down flat somehow to straighten it, pushing in only where it is bend outward, probably with some wood cut to a curve opposite the shape of the bend.

However, in the interest of time I'll be just replacing it with an ex-Crystalyte rim from Ianmcnally, then after I fix it (someday) it'll be a spare or go on the 9C/GM from Icecube57 (if I don't end up using that one to run the cargo bike middrive).

Even the rear one on yours could probably be fixed. I did in DGA's rear regular rim not quite as bad, but so much so that I had to take the brake pads off to let it roll at all (actually I did this TWICE, once right after fixing the prior one!).

 

[FMB42]

I agree with those that recommend a new rim and spokes. I say this because aluminum doesn't always take well to being "reformed" and, spokes are not designed to "straighten" bend rims (using the spokes to "straighten" a rim will often result in having no choice but to over-tighten certain spokes while, at the same time, under-tightening other spokes).

 

[dogman dan]

I have to agree, that's pretty bent, and for high speed use not good.

I bent my rear hub 9x10 rim a lot worse on a clumsy curb hop, got it about as straight as your bent rim, and have rode it a few times. But it's never going faster than about 10 mph in the dirt, and now that it's cooling off, I've started pedaling again on my super nice specialized. It's handling makes pedaling well worth it. By next summer, I'll get it a new spoke set and rim for sure. I didn't try to overtighen any spokes too much, because I don't want to break the flanges on the motor. I just ran one side of spokes tight enough to get it straight enough to not rub the frame. The other side is somewhat loose, and creaks like crazy.

If you want to, you could straighen that rim some, and run it for a few weeks while you sort out the options for getting it fixed right. Just go slow enough for one brake. On the bent rim, you won't get much out of the brakes.

 

[Floont]

A 530X is a serious motor, how fast do you normally go? if an undiscernable stress-fracture develops and grows into a catastrophic split, are you OK with that, at the speeds you normally travel?

If it was a 20-mph bike, maybe it wouldn't be worth worrying about, but few people who invest in a 530X stay below 20-mph...

Good point. 2 minutes prior to the wreck, I was traveling at 45MPH, then I was testing the speed switch settings that I had flashed in the controller earlier in the morning. I was at switch setting "I" which has a maximum speed of about 21 to 22 MPH full throttle on the flats. This is my economy setting. Switch setting "II" which tops out around 32MPH is my "normal" setting, so I need to consider any aluminum stress cracking I may have incurred that is not noticeable right now. A new wheel is probably the safest plan.

I don't want to go through another wreck again any time soon. I'm 48 hours post-wreck and I feel terrible (worse than yesterday).

FA

 

[The Mighty Volt]

Being honest, hospital bills cost more than a new rim. I would just splash the $50 on a new rim.

 

[amberwolf]

I don't want to go through another wreck again any time soon. I'm 48 hours post-wreck and I feel terrible (worse than yesterday).

Not surprising...all the toxins and whatnot from dead cells being disassembled and replaced probably don't help any; it always feels like those build up more when I lay around after an injury of any kind as opposed to keeping myself moving and active, and the pain seems less when active, as long as I avoid stressing the actual injured areas. Sometimes it has not been possible to keep active, depending on the injuries, and how I got them (most of mine are not from bike riding).

 

[spinningmagnets]

2 minutes prior to the wreck, I was traveling at 45MPH

Holy Crap, Batman...don't even think about it. New rim for the 530X! If the old rim is somewhat "fixable" maybe use it on a pedal bike? (everybody needs at least one manual-input bike as a back-up).

I know this particular wreck wasn't your fault, but...I highly recommend a front disc brake (It doesn't look like you have one right now)

 

[Floont]

2 minutes prior to the wreck, I was traveling at 45MPH

Holy Crap, Batman...don't even think about it. New rim for the 530X!...I highly recommend a front disc brake (It doesn't look like you have one right now)

Yep. As soon as I get some mobility in my limbs such as bending my right elbow and having the ability to squat, I'm clipping those 12 gauge spokes and pepping the 5304 for new spokes and a new double wall rim.

Unfortunately, my old front forks don't have a mounting point for disk brakes, otherwise I'd have those already. So, I'm going to replace the broken caliper brakes with Bulldog Brakes

 

[thedarlington]

a friend told me u can fix it by putting it inside a door jam, closing it and trying to straighten it out, i wanted to try it but i think it has to be a larger door because the ones at my house wouldnt accept the width of the rim inside that gap

 

[Floont]

.
At the speeds I attain at times, I want a perfectly circular balanced rim. So, I'm not going to fix this warped one. There's too much vibration at various speeds and I certainly don't want a failure from an unseen stress crack to create another accident.

Thanks for the idea, though!

FA

 

[thedarlington]

hey man is that pic on ur profile from when u had the fall? yea i dont know if id try it either seems like it was pretty rough, i know what that feels like, just 2 weeks ago i was going about 20mph and i hit a parked bike on my bike lane as i was squeezed between that and traffic, it really sucked but amazingly, i was ok besides some knee swelling, rim was ok, but fork was warped to one side and it messed up the brake alignment, i cant complain tho, i can imagine what a crash in a car even at that speed would of cost vs just a fork, so maybe having to only buy a rim aint too bad after all

 

[Floont]

hey man is that pic on ur profile from when u had the fall?...

Sorry about your knee. I hope it heals quickly! Sorry about the wreck too, but your health is more important.

Yes, the avatar picture is me within minutes of the wreck. Believe it or not, I took the picture and I have no memory of doing so. I did a few other things I have no memory of, like picking up broken parts and my phone off the pavement. The picture was taken before I passed out. I figured that out from the time stamp on the picture file.

BTW, does my avatar picture offend anyone? The reason I ask is that Photobucket.com removed my photo saying it violated their "terms of use" and was inappropriate, so someone must have complained. I think I'll start a new thread asking this question after Photobucket responds with their explanation of why they removed the picture. I read their "Terms of Use" and it does not violate anything specifically stated therein. I'm kind of pissed off at them for removing it and not sending me any email notification or justification for their action. :x

FA

 

[Ykick]

Trying to save a bent rim for use on a high speed bike is penny wise and pound foolish IMO. Even if you get it rolling fairly smooth - I had mild damage once that I trued and kept running. The slighly mis-shaped edge wore through the bead and sidewall. Eventually the tube broke through and blew out - crazy failure!

 

[Floont]

.
I agree.

I'm trashing the rim this afternoon. A new one is already on order.

FA

 

[docnjoj]

Quoting Floont:
"BTW, does my avatar picture offend anyone? The reason I ask is that Photobucket.com removed my photo saying it violated their "terms of use" and was inappropriate, so someone must have complained. I think I'll start a new thread asking this question after Photobucket responds with their explanation of why they removed the picture. I read their "Terms of Use" and it does not violate anything specifically stated therein. I'm kind of pissed off at them for removing it and not sending me any email notification or justification for their action."

Having done a bunch of ER work in my career the blood is not offensive. It would, however, be a more hopeful sign if you showed pic's of yourself healing. It's a bit more encouraging to the rest of us who also have had accidents.
otherDoc