bent rim

Stephen Shope /

my tomos sprint has a slight bend somewhere in the front tire. It is enough to make a wobble. I know that you can true up a spoked wheel but can you fix a mag wheel? Is there any method I could use to find the bent part and bend it back?

Re: bent rim

Sure it mounted right?

Re: bent rim

yeah I would check all the mounts extremely well before you decide that. but I do not know of any ways to fix a mag wheel. might have to take it to a machine shop or something.

Re: bent rim

Just clamp a piece of wood or something to the fork near the rim and rotate the wheel.. the gap between the wood and the rim will vary if the rim is bent. I've seen tires that inflate unevenly and cause what looks like a wobble.. like really cheapo tires or the innertube is bunched up in one spot.

Re: bent rim

Don Pflueger /

or just grip ths fork with your hand and place your thumb close to the rim and hold your hand steady as you turn the wheel. and like joe said, ive seen cheap tires and tubes (cheng shin brand) that dont inflate evenly and make a wheel look bent. but if a mag wheel is bent, it sometimes can be pressed back into shape, but they become weak and may break.

Re: bent rim

If I find the bent part what would I use to bend it back? I am pretty sure it is bent because I will put the bike on the kickstand then lift the front tire off the ground and spin it and while it is spinning the wheel will stay in one constant spot the it will jump over to the left a little bit then jump back. How can I know if the mounts are straight and even?

Re: bent rim

Don Pflueger /

if it (the rim) stays straight thru most of the revolution, then hops to one side, its definetly the rim.

Re: bent rim

maybe find someone with one of these, call and get a cost estimate:

http://members.aol.com/wheelcrafters/page0003.html

tire/wheel dealers.. salvage yards? hmm..

Re: bent rim

it couldnt be a bad bearing or something inside the hub could it, or a loose bearing?

just a thought

Re: bent rim

Don Pflueger /

not if the wheel tracks straight the hops to one side briefly then tracks straight again.

Re: bent rim

not necessarily.

Re: bent rim

Don Pflueger /

what do you mean? how would a bad bearing make a rim off set in one spot? its impossible. i build hundreds of bike wheels a year and i think i can pretty much tell you that it cant happen. and a mag wheel probably has a flat spot from hitting curbs.

Re: bent rim

I have an idea but I am not sure if it will work. What if I took of my front finder and my tire and tube. Then I put just the rim itself back on the bike. I could get someone to sit on it so the forks will be off the ground. After all of this do you think it would be possible to locate the bad spot by spinning the rim and sticking a peice of wood the part of the rim where the tire and tube goes that is the exact width of the rim and wherever the rim and the peice of wood are flush the rim is not bent but where the rim pinches the or seperates from the peice of wood it is bent?

Re: bent rim

Don Pflueger /

you dont need to take anything apart. just hold your hand on the fork and keep a finger steady and spin the wheel. you will be able to feel if the rim is bent or not. let alone see the bend.

mag wheels get bent from jumping curbs, and hitting pot holes. they get a flat spot in them which pushes the wall of the rim outwards.

Re: bent rim

On the link i posted about wheel straighteners theres's a line that goes.. " Heat ( Propane Torch) must be used with alloy wheels. "

So, although it's real easy to find the spot, what will you do then?

Re: bent rim

Don Pflueger /

i have a wheel press and a dish tool to fix them up.

Re: bent rim

cool.. i been searching for the procedure but no luck. What's with the propane torch? It doesn't seem to me it could heat an area of a wheel to any appreciable degree.

Re: bent rim

Don Pflueger /

its to soften up the metal to keep it from stress cracking as you bend it back.

Re: bent rim

i kinda figured that much ;)

so i guess there's nothing too hard about it.. if you have a die that fits the curvature of the wheel and heat it a little and slowly push, it's gonna straighten out.

Re: bent rim

Don Pflueger /

it will somewhat. keep in mind that as metal bends, it stretches. bent wheels can be made straight, but not perfect. and they may have a slight bump where two ends are welded together to form a circle. mags are usually done in a mold so they should be perfect right from the start, but once bent they will never be perfect no matter what you do. and its hard to find places that will repair them because its not cost effective labor wise. it usually takes me about an hour to true up a bicycle wheel that was bent pretty badly. i charge 445 an hour labor. new wheels can be bought at dicks for $25-$30. so its a waste of most peoples money to have me fix them. unless its a special wheel or they cant find a match to the other. i must have 200 used wheels in my barn that were bent and i sold new replacements. but i straighten them and use them for used bicycles that i sell that need a new wheel cuz one may be missing, rusted out, or too badly bent to repair. and i like to do stuff old school. its a dying art. not many wheel builders out there anymore.

Re: bent rim

I appreciate everyones help. I have a local tomos dealer near me so I guess I could take it to him. But if you did heat the bent spot up with a torch how and what would you use to bend it back? Would the heat not melt the rim and ruin the paint?

Re: bent rim

Don Pflueger /

yes the torch may make the paint bubble or burn off. i would use a vice to try to bend the rim back. its gonna be hard so be careful. especially since you dont have the right equipment.

Re: bent rim

Justin Brownell /

445 dollars an hour labor. holy crap that seals the deal.

Re: bent rim

Don Pflueger /

$45 an hour.

« Go to Topics — end of thread

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account