Could This Bent Wheel be Causing Steering Wheel Vibration?
 

I've been dealing with some steering wheel vibration since I purchased my '07 C2S in March, and wanted to get some opinions from fellow Rennlisters who have experienced similar issues. I've searched and read many threads that point to either balancing (the obvious first culprit) or another front suspension or steering component (tie rods, control arms, etc.) but I don't think either of those are my issue.

When I first bought my car, I noticed a significant vibration in my steering wheel between 65-75mph. My first thought was balancing the tires. I had the coil packs (cracked) and spark plugs changed at my Indy, and asked if they could balance my tires while they had it. They said one of the fronts (didn't specify which side) was out of round and they couldn't get it to balance. The PZero's in the front that came on my car were over 6 years old and were on my short list to replace anyways, so I replaced all 4 corners with a new set of Michelin PS4S's that were road force balanced at Discount, then aligned at my Indy. I set the tire pressure myself and they have maintained proper pressure since I had them mounted.

The Michelin's were a huge improvement all around, but I'm still getting some steering wheel vibration in that 65mph range. I thought it could have been minor flat spots due to sitting for a couple of weeks while I was on vacation and while I was waiting to get back into my Indy for a cracked coolant expansion tank, but the vibration was still consistent with an out of balance tire (flat spots would vibrate at all speeds, not just a certain range). So I had it back at my Indy last week for the coolant expansion tank and asked if they could re-balance the tires, thinking that Discount didn't balance the tires properly. They balanced all 4 and said there were a couple small weights that they shifted around, but not all that much different than where Discount had placed the weights. I had pointed out the slight bend in the driver's front wheel when I dropped my car off with them, and they said that is most likely what is causing my steering wheel vibration. I also had them give the front end a once over in case it was something else causing the vibration, and they didn't find any other steering/suspension components that were out of spec.

If two different shops said the wheel/tire balanced properly, why is there a vibration present still? My Indy said that sometimes with 911's, even with well balanced fronts, that there isn't enough weight over the front of the car and that small wheel bends like mine can cause a vibration that might not show up in a car with the engine in the front.

While pulling the wheel and having it straightened seems like the logical next step in trouble shooting, I wanted to see if anyone here has had such a small bend cause steering wheel vibration that couldn't be addressed with balancing. Just about everyone I talked to (friends, Discount Tire, etc.) thought that if this bend wasn't causing the tire to loose air, that there should be no problem getting the tire to balance with a bend this small.

With all of that, have any of you had a bend like this cause a shake in the steering wheel? Did straightening the wheel or replacing it solve the problem? @Bruce In Philly , it sounds like you've had a few bent wheels on your Porsche's. Would you have something like this repaired/replaced? Used Lobster's are going for around $400-$450, and repairing it will cost me about $200. Just wanted to get a sanity check before I pull the wheel and drop it off at a wheel repair shop for a week.

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The only way you can know for sure, is have your wheel put on a good machine.... or a cheap jig at a wheel shop. Regarding the cheap jig: My buddy purchased some real cool looking rims for his BMW 5 series from Tire Rack.... noted to be for his car. They kept going "out of balance"... we took the car to a wheel and tire specialty place down in Wilmington DE.... they refurb rims and do work for dealerships..... they guy just looked at his rims... and said something like "cheap Taiwanese crap". He took of his wheel and put the wheel/tire on a simple spindle.. and slowly spun it... wow, that thing was just bent. "See it all the time... Tire Rack". So my buddy purchased a used set of BMW rims from them.

Regarding the good machine..... I took my 2009 C2S with 19" wheels to get balanced in Ohio... had to take it to a Chevy dealer... Chrysler and Chevy dealers were the only ones who had a big Hunter machine with road force (I guess for Vipers and Vettes).... he came back and said two of my wheels were slightly bent. He was able to balance them thank goodness. The good shops, and these guys were one of them, will actually spin the tire in rim to get a great balance.

Only real way to know if that kink is detrimental is take it to a good shop. It may be very benign.

Peace
Bruce in Philly

If a wheel is out of round it absolutely can cause vibrational input once the centrifugal speeds harmonize with other suspension components. I once bought a set of used staggered wheels that looked good to the naked eye but once put on a spin balancing machine the two front wheels were discovered to be slightly out of round (presumedly from hitting road hazards - one bad pothole strike can bend a wheel). They could not be perfectly balanced because they were not perfectly round. I put them on the car anyway, had it aligned, and discovered from about 70-75 mph the steering wheel would vibrate. Solution? Drive faster or slower and the vibration ceased. Later I replaced the two bent front wheels with like new versions and the vibration ceased completely. You might be able to get your wheel straightened at a competent wheel shop.

Thanks, Bruce. Sounds like that is my best course of action.

That's my hope. I sent a picture to Woody's Wheel Works here in Denver. I found them online and they were also recommended by my Indy. Based on the pics I sent them (baring nothing major unseen), they said they can most likely straighten the wheel. Hopefully they can get me squared away.

Good luck, and let me know how it goes. Might have to get my new (to me) Carrera Classics checked out there as well!

Yep, will definitely keep you posted!

Could be tire damage too.

Peace
Bruce in Philly

Yeah, haven't ruled that out either. If straightening the wheel doesn't solve the problem, my next stop will be going back to Discount for a warranty claim. I watched a YouTube video about bent wheels and tire issues suggesting that tires can easily be damaged during shipping and receiving if they're knocked hard or bounced off the ground without the support of the wheel and air pressure to keep their shape. It's not unheard of to bend a steel belt that way, which could cause vibration.

If you can see a bend in a wheel with the naked eye, it's bad enough to cause vibration. I can almost guarantee that's your problem. A balancing machine can only do so much. When a wheel is out of round, the tech can get the wheel to balance on the machine, but there will still be speeds on the road at which the wheel will start to shake.

Get that wheel straightened, get the tire re-mounted and road force balanced and I'll bet you Dollars to doughnuts that your vibration goes away.

A bent front wheel and steering shake go hand in hand. If you only feel steering wheel shake on braking, its a warped rotor. My $.02.

It's sounding that way. I brought the wheel in today and they put it on a spinner in their office, you could see a slight wobble on the inside when they spun it. I'm bringing in my passenger side front as well since my car is up on jacks anyway. Might as well check both fronts since I'm going through the process. Stay tuned....

Hope you find the fix. Remember to have the spacers (if any) and wheel bolts torqued meticulously and in the proper (star) pattern -this worked on my 997. I also have had this issue with brand new MBs and Jags as well - very frustrating.

On another note I just got back from Vail, via Denver. Man you guys have some beautiful roads and scenery in CO (Rt 24 is one I was on on the way to Browns Canyon). How does your 997 respond to the thinner air ? I noticed my rental, a toyota forerunner , as well as myself, sucking wind at times LOl.

Thanks. I brought in the other front wheel this morning and while not nearly as bad, there is a very slight wobble when spun if looking closely. They weren't overly concerned with it, and I doubt it was the offender of my steering wheel vibration, but I figured I would have them straighten it anyway. I might even have them take a look at the rears when I pull them this Fall/Winter to be refinished. Whatever the front wheels hit with my car, the rears inevitably followed. I don't have spacers, and will definitely torque the wheels to spec using the appropriate pattern. I get the wheels back next Tuesday and will report back with an update.

Yeah, we're blessed with amazing scenery and fun driving roads here in Colorado. I live at the foot of a couple cool canyon drives on the Front Range. It's nice having access to roads like that in my backyard.

The altitude effects on both humans and cars is real. Thankfully humans can adjust, it's not as easy with cars. Modern cars can adjust the trim level based on altitude and air thickness, which is a huge improvement over the old carbureted cars, but there is no substitute when taking a car to sea level. Cars benefit greatly here from forced induction. I bought my 911 in Dallas and drove it back here. You don't notice a huge difference in performance in 1st - 3rd gear, but you definitely notice it when you're in 6th on the highway going 75 and you want to get to 85 to pass someone. It's just not the same here as it is at sea level.

BTW, the new 4Runners are grossly underpowered IMO, especially if you're doing any serious mountain driving or light towing. That's why I kept my '07 4Runner with the V8. :)

Yes. I had a bent front wheel that was causing vibrations. I replaced the wheel and the vibration disappeared and never came back.