What is That ?

[Mike52]

Had what looked to be a small crack in the front rim so I decided to fit a new one.
Threw it in the corner .
Just noticed it today because it is now very different to when I last saw it.

[JohnnyO]

They nearly always break after you unlace a cracked rim and the spokes aren't holding it together anymore.

[Mike52]

They nearly always break after you unlace a cracked rim and the spokes aren't holding it together anymore.

Didn,t know that.
Thought the stresses would be neutral.
Learn something new every day.

[Hoony]

is it an infamous early 80's DID jobby. ?

[Mike52]

is it an infamous early 80's DID jobby. ?

Na , infamous early Nordisk.

[firko]

I just threw out a infamous early 80's DID jobby from an XL Honda with the same split and I've got an 18'' Akront mudatcher from a Maico also broken right through....I can't bring myself to throw it out though, even though I know it's fruitless trying to successfully reweld it.

[PEZBerq]

Mike I have a Nordisk that did exactly the same - crack at the weld.  I am told that they make a bang if you are there when they finally spring apart. Obviously heaps of internal stress when they are welded in the factory.

Also have had one that wasn't cracked to my visual inspection but came back from being sent away to be re-spoked cracked  . I put it down to sitting around for 2 or 3 weeks before getting re-spoked and the stress caused the tiny crack to grow. The spokes stop them cracking by taking some of the stress off the weld. If you decide to replate your spokes then you have no choice but to leave the rim despoked for a few weeks risking cracking.  If you use new spokes I would get the spoke guy to cut the old ones and lace with new ones all at once to minimise the time in a highly stressed state.

I try to save the pale gold Nordisks as they just look right on a Husky. Modern rims are too gold  ..... but a certainly damn sight better quality than a 25 yr + Norwegian rim! Cheers 

[Mike52]

I have figured out how to fix these WITHOUT welding.
There is a method of crack repair used by engine reconditioners which looks like little dog bones.
Only $1000 for a kit.
Yer rite.
Back in the corner.

[DR]

Firko, just out of interest and you being a welderman, why is it fruitless to try and reweld rims successfully? I mean they are welded at the factory and it is only regular alloy. If it were vee'd and welded would this not work? Just curious as people do weld them and others say no way. When I sit and look, for me it appears the spokes and the triangulations of said spokes seem to be where the strength is, the rim takes some shocks yes but for most part it just carries the tyre.
 
Are not the spokes actually under tension and not compressive forces thus the wheel is being held in shape by all of these tensions balancing out throughout the hub and rim. Am I wrong? It doesn't sound like the best practice I realize but welding a frame, shock mounts and hubs doesn't seem to bother people yet this also has a potential for major disaster if not done correctly? It just seems to me the actual rim isn't the main load bearing item with stresses shared over the entire wheel. Curious is all. 

LATE EDIT: been thinking more and now it's beginning to hurt but mmmm..(new years res, don't think so much!) the lateral forces with a cracked rim could be the greater issue. If the rim is cracked then these lateral forces when turning hard into a loamy/sandy corner or berm where other forces are applied could distort the rims. This in turn would loosen spokes and loads would not be shared evenly thus a collapsed wheel could result from a hard landing on the next jump. hmmmm..the thlot plickens..best to buy a new rim and be done with it!

[firko]

Happy New Year Doc...They of course can be welded and I have done it in the past but if it's welded without spokes under no tension they often end up egg shaped and need to be rolled again. Then add the need to dress the weld, the cost polish then re anodize the rim and it's easier to find an decent DID or Takasago at a wreckers or on eBay. I actually have a welded Borrani mud catcher with my Michelin trials tyre on my 350 Maicos dirt track back wheel and it works fine but a DID that's actually split right through and spread like Mikes Nordisc is a different matter in my opinion.

[oldfart]

My take on rims is that they fussed together new at factory and rely on spokes to hold them true. I recon if you made a jig clean up both mating surfaces and re-fuss together and that would be suffice.

[Mike52]

I rekon this might work. Better if only starting to crack .
This is the $1000 a kit I was talking about.

http://www.locknstitch.com/Metal_Stitching.htm

[DR]

Happy new year Mark. Was interested to hear your take. Never had a rim welded personally but I knew there'd have to be more to it. I do have a couple of wheels with seam splits just starting and it's a real bummer when otherwise they're perfectly good.

Mike, that kit looks good but wow..it'd have to be a preeetty rare thing to spend that much on a repair..

[frostype400]

I have noticed some cracks on some of my pe rims D.I.D. jobby's always on the join too haven't figured out what to do yet they would spread if the rims were not laced.

You can spot them right through though I don't ride the ones with cracked rims though that might be asking for trouble.

[Mike52]

Mike, that kit looks good but wow..it'd have to be a preeetty rare thing to spend that much on a repair..

Yer was expecting a couple of hundred but there is only ONE agent in AUS , in Mackay, so I guess he can charge what he wants.
The kits come in all sizes from tiny to huge and for alluminiun as well.
Bummer cause it looks as if it would do the job no worries.
Tends to pull the crack together when you hammer them in.
Have seen these in alloy head repairs and they do look good.
Just like little stitches from the doctor.