Reminder to everyone: Check your wheels for damage.

[breakaway500]

Was at Whiskey Hill last Friday and the final session out was really putting the whip to the Atom. In turn 9 I heard what sounded like a tire snake whipping around the left rear.Kind of a "whap..whap..whap..whap" sound. As soon as I was straight,no noise. I pulled into the pits…checked for anything odd...didn't see or feel anything..and went back out,slowly. Noise was still there, but only in turn 9. Hmm.Not good...must find problem. I brought the car home..thinking it may be a bad wheel bearing..or loose suspension bushing.

I had lowered the back end over the winter and added heavier springs, and the wheel rim to control arm clearance was fairly close,so I assumed the springs must have settled in and the wheel had rubbed the control arm just a bit, as there were some rub marks on the edge. I added a 5mm wheel spacer and took the car back to the track yesterday. I went out slowly, and sure enough the noise was still there. Brought it in and decided it must be a wheel bearing. A few others even looked at the problem and decided that the very subtle wheel movement must be bearing related.

I just removed the wheel bearing from the upright and could find no signs of wear or damage. I then decided to take a real close look at the wheel.

It didn't take much to see the real problem:





Two broken spokes..out of 4.

How can something so basic, and easy to see, be overlooked! I wasn't looking for a cracked wheel. I feel so stupid...

These are 3 piece Keizer wheels..and the center is magnesium. I just got off the phone with Keizer...they were surprised to hear that a hub had cracked..however,it does happen..and they do make a billet aluminum replacement, which is MUCH stronger. I ordered replacements for all my rear wheels.

The thought of that center breaking is not something I want on my mind..


Moral of the story..do not assume anything is unbreakable.When looking for a problem,look at every possibility, including something you think is unbreakable…and check your wheels,closely every chance you get..

[TroyV]

Good stuff Mark.

Glad you found that before it turned into something catastrophic.

[Mick]

Thanks for the heads up. As TV said, glad you caught that!

[cuda6666]

Had that happen to the left rear on my Cuda going over the top of turn 1 at Mt Tremblant. Symptom was a sudden loss of air. I didn't figure it out until I was at the gas station trying to re-inflate the tire.

[cmm3]

Wow glad you were able to catch this before the wheel self destructed at the wrong time.

Brake dust can hide cracks and make it more of a project to check wheels for them. It's a bit of a PITA but after every few events I scrub the inside and outside of the wheels I've used to get them really clean with a scouring pad and degreaser. Then I give them a really give them a good visual inspection before putting them back on the car or in the trailer. It become a habit after one of our members crashed into the wall hard coming onto the back straight at NHMS a few years ago with a failed wheel being suspected as the probable cause.

Time is free and staying safe should make checking your wheels and car in general over carefully and regularly a standard practice.

This is a great reminder that all metal fatigues over time and something is bound to fail eventually.

[dantheman]

thats why they make rims just for racing on the track
curious how much magnesium and a set of billet aluminum rims cost ?

[breakaway500]

My Keizer wheels cost about $425/wheel with magnesium centers. The rears are 15" tall by 13" wide and weigh 11lbs. Very light for the size. The wheel is made in 3 pieces and bolted together.RTV seals them so they don't leak(in theory..)The shells are forged aluminum and the centers are magnesium or billet aluminum.The billet adds about 3/4lb to the weight if you choose that option,but is substantially stronger than magnesium. One nice thing about the 3 piece design is if you need to repair a wheel,(bend it, break it, etc) all you have to replace is one of the components. Most 3 piece race wheels are expensive,regardless of brand. The replacement aluminum billet centers will cost about $150/each. I've put a lot of laps on the Keizers and this is the first time I've had to repair one,so although I hate to see stuff break,it really is part of the game. Build it..break it..make it stronger.

[CalypsoBean]

Coming back from NHMS last event I could feel a slight vibration in the front of the car at certain speeds. I pulled over and took a look to see if anything was bent.

All parts were straight - but there was a strip of aluminum carved out of the inside of each front wheel all along the lip. The suspension had settled to the point where the clearance between the bottom of the ball joint and the wheel was minimal, and under stress they were making contact. Wheels are...finished for track use, let's say.

[6PAK72]

People ask me why I'm a wheel nazi.