CMA's on my latest project not good news!!!

[Shep57]

Sadly the front rim failed today when inflating a newly fitted tyre!! Not a pretty sight!!

 

[grandpaul]

Oh, my! Thankfully you weren't hurt (I assume)

 

[Shep57]

Oh, my! Thankfully you weren't hurt (I assume)

I'm ok but the tyre fitter got a few bumps and bruises, it was quite spectacular!!

 

[concours]

Sadly the front rim failed today when inflating a newly fitted tyre!! Not a pretty sight!!

What are the identification markings on the rim?

 

[Shep57]

What are the identification markings on the rim?

None as far as I can tell, but I was told they were CMA's

 

[concours]

None as far as I can tell, but I was told they were CMA's

How did you clean them?

 

[Shep57]

How did you clean them?

P600 to P1200 and solvol on the rims, Paint stripper removed the remaining paint then sprayed with Etch primer and three coats of rattle can top coat.

 

[concours]

P600 to P1200 and solvol on the rims, Paint stripper removed the remaining paint then sprayed with Etch primer and three coats of rattle can top coat.

I can't see any of that.
Must be a photo anomaly.

 

[Torontonian]

Wow , Can't imagine what would have caused such a fracture .

 

[Shep57]

View attachment 124703

I can't see any of that.
Must be a photo anomaly.

I just got them presentable from the sorry state they arrived with me, I'm not a concours type of guy, if you're looking for perfection you're in the wrong place. The polished rim sections were white with corrosion but still had the old tyres fitted until today's visit to the tyre fitters, hence the internal mess.

 

[Onder]

It's not so bad, it will buff out.....

 

[trident sam]

None as far as I can tell, but I was told they were CMA's

definitely CMA, I have a set.

 

[MichaelB]

Do we know if they are Aluminum or Magnesium?

 

[cliffa]

Sadly the front rim failed today when inflating a newly fitted tyre!! Not a pretty sight!!

Seriously - Be thankful it didn't happen on the road. Any CMA wheels have to be getting on for 50 years old I reckon, so who knows what trauma they may have suffered in that time. If I'd bought a bike with them fitted, they'd be the first thing to replace or get x-ray or crack tested.

 

[Shep57]

Seriously - Be thankful it didn't happen on the road. Any CMA wheels have to be getting on for 50 years old I reckon, so who knows what trauma they may have suffered in that time. If I'd bought a bike with them fitted, they'd be the first thing to replace or get x-ray or crack tested.

Agreed I used my dye pen stuff to check and they were fine, but the violence of the trauma has caused a few cracks to show post event. No sign on any dye anywhere in the cracks or in the broken area, in my basic worksop I did as much as I could I think.

 

[cliffa]

View attachment 124703

I can't see any of that.
Must be a photo anomaly.

It looks as though only the spokes and inner rim were painted.

Compare the arrowed areas. I reckon it's been cracked for some time at the upper arrow (dark stained crack ), and the stress of the tyre fitting and inflation caused it to rip open around the rim (clean metal crack)

 

[concours]

It looks as though only the spokes and inner rim were painted.

Compare the arrowed areas. I reckon it's been cracked for some time at the upper arrow (dark stained crack ), and the stress of the tyre fitting and inflation caused it to rip open around the rim (clean metal crack)


View attachment 124720

You are spot on.I saw those darkened areas.

 

[ashman]

I bet the tyre fitter filled his underpants, I seen a split rim explode once and it went off with a big bang, lucky the tyre fitter wasn't standing in front of it, he never did split rims again after that and he did fill his pants, well lucky that didn't happen while riding at speed.

 

[MichaelB]

That's wicked looking.
As a wee lad I worked in a tire shop.
Heard stories but never witnessed one.
I was taught not to lean over the tire/wheel, stand back and turn your head when filling a tire.
This is why.... Easy to forget and get lackadaisical... Glad the tire buster is OK.

Same techinique when turning on circuit breakers BTW..

 

[hybridracer]

I think long term corrosion. The worst CCC aluminium castings can fall apart under their own weight after a few hours of exposure to salty mist if you live near the coast. I have seen cast aluminium railway trolley wheels go very brittle after decades of being left exposed to the elements.