Dirt Bike Rim Repair

[Jigantor]

This thread has been posted for entertainment only.
I do not recommend the repair of rims.

After dirt bike riding on the weekend I was cleaning the bike and discovered 3 small cracks in the rear rim of my KTM.
This is a Excel ali rim.
Two of the cracks were near the original welded joint, the other was in a section of the rim that had been bulged, most likely from landing on a rock.

I power wire brushed the rim to clean away all the dirt, rubber and contaminants.
I then placed the rim in a 20 ton press and removed the bulge.

Ji

[Jigantor]

With a grinding stone the cracks were Veed on both sides then TIG welded.

Ji

[aametalmaster]

Nice fix...Bob

[Jigantor]

Thanks Bob.

I will post a picture of the polished rim when I can get a good image of it.
I took some yesterday after a few minutes sanding but it is just like looking into a bright light.

I will have another go today.

Very pleased with the result.
KTM sell this rim here in Australia for $617.00.
Our spoke guy can drill out a blank rim for $320.00.
And there is a chap selling a rim on Ebay for $270.00 delivered.

Seeing how the rim cracked away from the original joint this leads me to believe that the ali is fatigued and will just crack somewhere else. I will monitor the rim as I do all the critical parts and replace it if it happens again.

Ji

[aametalmaster]

I wouldn't worry about the repair. Welding on an alum wheel is proper as long as its done right. I have plenty of links for repairs but can't seem to find any except for heresay that says you can't weld them...Bob

[Jigantor]

Hi Bob,
I agree that some may have gone too far.
The flange is folded back on itself and over the years the gap fills with dirt and oxidation.
When grinding the Vee you don't see the gap or the dirt, but when the arc starts the filth floats up.
I stop, grind or wire brush and start up again, until I am welding clean ali.

Old DID rims get pretty bad after a few years and their ali starts to flake. Virtually impossible to weld.

Ji

[mx842]

Where as I don't blame you for trying to fix what you have considering the prices you quoted. Hopefully that is a complete wheel but you should be able to get a bare rim for around a hundred bucks or so and I have seen them on e-bay for between 50 and $100. You need to check out MotoSport.com I'm sure they will ship over seas here is a link to a page I just went to and it shows Excel Pro complete wheel spokes and hub for 285.00 brand new. They have several other brands some cheaper, some more but they have it all with pretty good pricing on just about everything. http://www.motosport.com/dirtbike/pr...EEL/?id=108733

When we were racing I fixed a lot of them some worst than the ones you posted but once they start cracking they are never right anymore. I used them for spare wheels and for races at wet sandy tracks where we needed a special tire that was only good for that kind of duty. It's good to have a spare wheel or two anyway because those sandy tracks are heck on the finish of those pretty shiny yellow and blue wheels we ran when I could afford them.

[Jigantor]

Hi mx842,
Those prices I quoted were for just a bare rim.
No spokes, nipples, hub or lacing.
The rims in the States are cheaper than here but the postage is the killer.
A rim costs another $100.00US to post.

I do agree that I think when they start cracking they will not stop.
It will be a fatigue issue.

Ji

[Jigantor]

Attached is a link that shows the kind of prices we have to pay for MX wheels and rims.

http://www.ballards.cc/catalogue-2011

Ji

[gordsgarage]

Nice work Ji, I think the fix is well worth a try. If it continues to crack the effects will not be catastrophic. You've lost nothing.

Gord