Rim got cracked. Is this dangerous to use?

i2000s

i2000s

1 W
Joined
Oct 8, 2016
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I hit on a rim on the margin area of a road to avoid a car blocking the way, but I fell over the bar of the bike and the front tire got exploded. In my further check, the double-well rim of the front wheel got cracked yet everything else works fine. The front wheel is the 26in motor wheel and seems still well connected with the spokes and motor in a good shape. Given the crack has been cutting through the rim entirely while I am not a heavy guy, should I do something about it? Or, it is still safe to ride around on a relatively flat road with only a few pothole areas?

Thanks!
 
9BHx1

Cracked rim https://imgur.com/gallery/9BHx1
Here is the photo. Sorry, it's too big to upload at the beginning. I feel it's ok still and put a plastic board between the rim and the tube to cover the sharp edges, but not sure if it worth me some hard work to disassembly spokes and redo them (no experience and it's expensive to me).
 
It looks as if it is just the rim joint not a crack. Rims are made out of profiled straight aluminium that gets rolled and joined together.

BicycleRims-COMP.jpg

86450-largest_1_Renn_rim_joint.jpg

Your rim:


So I don't think you have a cracked rim and don't think you have to worry about it.
 
Interesting to see this! Does every double-well wheel rim have this type of joint? I didn't notice this before, and no idea how would this impact my daily usage...
 
As far as I'm aware 99% of aluminium rolled rims are joined like that. Search for the joint in your rear rim and see if you can find it.
 
As far as I'm aware 99% of aluminium rolled rims are joined like that. Search for the joint in your rear rim and see if you can find it.
Click to expand...

Ok, I indeed found this type of joint on my rear rim, although it's tightly joint. Thank you for pointing this out!
 
Epoxy itself is not strong. Carbon fiber uses epoxy as its' matrix and gains perhaps 1.5% of its' strength from it. The idea would be to use a strip of fiberglas or better on the inside of the rim. I don't know how well you'll get the epoxy to bond to the aluminum. I'm not recommending that as a good idea, it's just better than merely using epoxy.
 
It's also a poor quality rim if you can feel sharp edges. You can try filing the ridges smooth, but really you need a better rim.
Click to expand...
Those edges might be caused by my hitting on the road curb the other day. I was totally rolled over the bar under a high speed, and the tube was exploded right around the rim joint position. I would like to find a way to smooth the sharp edges. Filing the ridge doesn't seem to be a great idea to me on the aluminum material, but it may work well... I don't know how to do the epoxy at all.
 
The structural strength of the joint is probably ok still, as the pins are there.
By removing the tyre+hose and file the sharp edges away, it should be usable.

I would change the rim before starting with carbon and epoxy.
If you don't have experience with those methods it probably will be a questionable improvement.
But what theoretically could be done is some rowing or thin cloth on the inside over a length of ~10cm.
The aluminum surface would have to be cleaned from paint and brushed and free from fat.

Is the rim still true or very close to true?
 
It's safe to ride,, as others said. But it's clearly bent,, I'd still want a new rim on it by summer,, or now if you are in warm climate.

I just loathe a bent rim, with V brakes.
 
Ok, after a few days of riding, the joint part seems to have been filled with the black materials from the brake pads. I haven't gotten a chance to take further action to make the sharp edges smoother. But this filled up material might be helpful to reduce the future threatening to the brake pads. The rim doesn't seem to be bent. I guess I shouldn't worry about it too much for now.
 
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