Joshboody

Checked my balance today, due to vibration at speed... according to Discount Tire, ALL my wheels are bent. They showed me 1 wheel and I can see it when spun on the car, but others are not obvious to me.

18 x 10.5" OEM Speedlines

I've had a Discount mount 2 sets of tires on these wheels and they did NOT say anything. Its been 5 track days since the last mounting.
I do jump curbing sometimes depending on the track, which seems to be fairly common with many drivers.

Is it common to bend wheels on track??

Jay_Davis

Shouldn't be. For me its been much more likely to get bent on street potholes.

JeremyGSU

I would say no. I ran over 20+ events at Sebring which is a pretty tough course running over the rubble strips on the OE wheels and a set from House of Wheels and never had any issues.

Nowanker

Ditto on the potholes.
How bent is bent? I see a lot of bent wheels when I'm mounting/balancing, but mostly they're inconsequential and I don't even mention it. Sometimes they're bad enough to note (1/2" runout?), but I'm always amazed how undetectable it will be driving.

CHJ In Virginia

There is no way that running over a few gators on track will bend your factory speedlines. The only way to really check a bent wheel or out of round wheel is to chuck the bare wheel on the tire machine. Use a dial indicator hand rotating the wheel and you will get the true story. You need to measure both lateral and axial runout. Your eyeballs are not calibrated enough to gauge a runout problem unless it is extreme.

Joshboody

Thanks guys.

The tire guy showed me the 1st wheel on the balancer, which was obvious (although I have no experience). He then checked the remaining and said they were all similar, but I didn't see for myself. Back home after mounting, the 1 wheel did seem to be bent when spinning and still a little shaky at higher speed after balancing.

I have a track day Sat, which I'm gonna run em. Afterwards I'll take them to another shop. Seems very strange that all would be "very" bent... they stated this is not normal with all the wheels they see. Either tire shop before didn't notice or tell me... OR I did some crazy curb jumping since then.

Here's a lap from last event which is prob the harshest curbing in the tracks I frequent.

fatbillybob

OP,

If you don't have the proper equipment to check for wheel runout the ghetto way to check your wheel is to buy a cheapo harbor freight dial guage with stand. Then put your wheel on the car and jack the car up so the wheel is free running. Then put the pointer of the guage on the rim and check both vertical and lateral runout. You are then assuming good wheel bearings. While driving 75mph+ You might be able to feel 0.20" out of round if very tuned in with new tires. You can for sure feel 0.40" out but not care if just tracking. A clue to wheels out of round is the tire guy has 2+ oz. of weight to balance the tire. You can also take a hydralic ram and bend the tire back if you know how and are careful. I check annually and bend them back if I need to. The ones I had to bend back the most were the expensive CCW's from when we ran them in SCCA T1 days. I jump curbs racing just about every race if we are in close quarter battle. If I need to use that piece of track I do it. If it yields a lower laptime I do it in qualifying. I also run improper low tire pressures on Dot-R tires which put more impact on the wheel and honestly I don't have a problem with bent wheels. I'm using cheap F14 forgestars and factory C5Z06 rears. I quite surprised the cheap forgestars hold up to the abuse I give them. I have definitely paid more and gotten less with other more costly brands.

I also mount and balance my own tires because I go through them so fast. Make sure the tire guy is imputing data into the balancer machine so the tire gets the proper balance. It needs stuff like rim width, where you are going to mount the weights, and wheel diameter and know the offset. Few tire guys ever change the settings for your wheel or even calibrate the balancer with a test wheel. Many balance problem are operator error. A clue to operator error is if you drive and have an imbalance. Then strip the weights off and drive again and there is positive change.

Joshboody

Thanks, great info! Prob pick up HF dial and stand today.

Messaged OE Wheels on their repo 18x10.5... 35lbs!! Getting harder to find OEMs now and little worried many could be bent also.

Nokones

I am definitely not an expert on this subject but, unless the wheel was forged/casted/machined out-of-round to begin with wouldn't be nearly impossible to bend a cast/forged wheel under any circumstances including using a very old Coates tire machine? Unless the wheel is steel, wouldn't the wheel just crack/break under pressure?

Nowanker

It probably more common to find a bent wheel than one that's laser straight!
When I'm mounting/balancing I find one that has no run out to be truly remarkable.
They just bend.

69autoXr

That's probably the shipping weight. The OE Wheels C6Z 18x10.5 replicas are 23-24 lbs.

TKOGTO

70+ days, never bent a wheel, stock or CCW.

Joshboody

69autoXr

Socko

One of my front 17" c5z wheels was always bent, I bought the car 9 years old with 30k on it. My alignment guy showed me. It was visibly bent on the machine and he said its probably good enough. Only took 3 sticker weights to balance and I could never tell.

My take is all wheels are bent if you ask a machinist, because they all have some runout I'm sure. The amount it takes for an average person to feel it is LARGE and visible, so even if you can see it, it's possible it is good enough.

So to say track curbing can't bend wheels is difficult, I can say my car never had any issues I could feel cause of it.

davidfarmer

18x10.5 c5 speed lines are 18lbs, amazingling light. I bent one at Road Atlanta last year, caught it HARD on the backside of the turn 10a apex curb (heavy traffic). I've never bent one in 25 years of normal driving on track even with heavy curb usage. The tire can absorb and distribute a huge amount of energy

Nowanker

My take on it as well. Mounted a whole bunch of tires over the years (part of my job...). MOST wheels I saw were visibly bent to some degree. Not talking a lot, 1/16", 1/8", or less, but some so bent they look like they'll jump right off the balancer. And even most of THOSE weren't detectable driving. I rarely saw a laser-straight rim.

Glowing Rotors

I had a couple of C6Z OEM speed lines bent about three years ago. I think an inexperienced tire hand at my previous the tire shop did it, but I can't prove it. I found a better tire shop who had tools to straighten one out, but the other one was scrap. That better tire shop now does all my tire business.

Joshboody

Good info. Had them weigh upc 4750666 at 24lbs also.

Joshboody

Measured runout of 4 wheels mounted on 1 hub.
Radial front side: .01 - .03" (dial on surface where valve stem is)
Radial back side: .11 - .24" (edge of the barrel)

I take it actual runout would be avg of the 2 readings? From online and wheel specs >.10" is high. But according to this thread, no biggy. I'll just try to keep the higher runouts in the rear.

lateral was: .02 - .06"

Another tire related subject is my tires are rotating slightly on the rim, but these are 200tw and rear rotated under acceleration (unless it did a 360). I'm assuming its the tire shop's poor prep... I've heard of this with slicks but seems should NOT happen with street tires.