After about 35 Auto-X laps my Powder coated AP2 V1's almost failed!!

7 of 10 spokes had cracks.

3 of the 4 wheels had cracks.

1 more lap this weekend, my CR would have been seriously F'd up.

A friend spotted the cracks and said, Whoa, don't go out again at the last second.

Whew, that was too close for comfort

 

ouch man. those are good looking wheels too.

 

so these cracks are from powdercoating?

 

talk about wheel failure

 

When powdercoated.. The wheels are baked at 400F.

The working theory is that this extra hot heat cycle weakens the aluminum.

Then by stressing them with autoXing speeds and forces, they cracked.

Bear in mind most of those laps were on a very high grip airport surface.

 

i was thinking of pc'ing the v1's on mines.... but thank goodness i read your thread.

maybe i'll try vinyl wrapping it.

 

so the whole wheel cracked, or just the powdercoating?

 

It seems that if you bake them at too high a temp then things happen. My old AP1 wheels never had issues after I had them powerdercoated. A good friend of mine however has a set of SSR Comps powerdercoated and they basically bent right where your wheel cracked so the tire was inboard about an inch from where it was at the start of the autocross run. That was on street tires. I wish I had pictures....

 

Interesting. I know that hod rodders had some big time problems with chroming suspensions parts, e.g., springs, a-arms, etc. The process weaken the metal causing it to fatigue and fail. In some cases resulting in serious accidents.

Good thing your buddy saw it in time!

 

We had the same thing happen with a set of SSR forged wheels. We sent them back to SSR and they had them tested and significantly softer than original. The problem is the heat.