TexasZ06

Just purchased a 99 Vert in Maryland and drove it back to Texas. Great drive with a stop at the NCM in Bowling Green

Unfortunately, as there were no real highways near the dealership only got it up to about 70 mph on the test drive so didn't notice the rhythmic vibration at about 80 mph until I had paid and left. I noticed it mostly in the gas pedal, but could also feel it on the door handle... definitely nothing in the steering wheel and don't think there is really anything in the seat either.

Brand new Hankook tires (dealer put 245/45/17s and 245/45/18s on all 4 corners because they were not paying attention) on knock-off rims, so I figured it was a wheel balancing issue. So when I got home, I took the tires from my Z06 (only about 1000 miles on the tires) on OEM Z06 wheels and moved them to the Vert. These were recently spin balanced and caused no vibration on the Z06. With these on the Vert, the vibration comes at about 55 mph and goes away at about 70 or 75 mph. Can feel the vibration in the same locations.

Having read all of the threads about the Road Force Balance, it had me thinking that this would be the logical next choice, but then since I had never felt any vibration in the steering wheel with either set, I figured the fronts of both sets must be OK so I put the front knock-offs on the front and the front Z06 wheels on the back. But the vibration is still there, this time at 75 or 80 mph.

I have checked the wheel bearings using the method suggested in other threads of gripping the rotor at 12 and 6 to see if there is any play and do not seem to have any issues there. Rotors appear to be in good shape, with no evidence of warping.

Would really appreciate any thoughts on a list of things to check from here and a logical order to check them.

$$$frumnuttin'

If I read you right, you put known good balanced tires/wheels on the problem vehicle and still got the symptom, but at a higher speed. This tells me it is not related to your wheels or tires. However, if you can drive through the vibration it is always due to balance, but you must feel it in the steering wheel. It will oscillate as you go down a smooth road that should normally not produce any feel whatsoever. So, there is conflicting effects because you said you feel it elsewhere than in the steering wheel. You really need to take it to your dealer and have a lot of things checked out by a skilled mechanic. One thing you can do at home is jack your car up and spin the front wheels by hand as fast as you can, then watch for any runout. It doesn't take much to be able to actually see the wheel or tire moving in and out. Industry specs allow .100 runout on OEM wheels. If you have aftermarket wheels anything can happen depending on the manufacturer.

00Corvette

What is the difference between a "road force" balance and a regular tire balance??

Donnie

TexasZ06

With a regular tire balance they just spin the tire. With a road force balance using a Hunter GSP9700 (www.gsp9700.com) it spins and then also another wheel applies force which gives the effect of the weight of the car sitting on the ground. This machine will help match a high point or stiff spot on a tire with the low spot on the rim to maximize the roundness.

If you search road force balance, you'll find a ton of threads on the subject. They solve issues that spin balancing cannot, but it will cost you more since it is more labor intensive and apparently you need to watch the techs in many cases to make sure they actually do all of the steps and don't rip you off.

00Corvette

thanks so much!
Donnie

TexasZ06

Yes, it is going to my mechanic later this week, I just like to be able to give as much information as I can to avoid as much diagnosing time as possible. Just looking for other things that I can look at to try and narrow the field.

Billdog350

FYI, in regards to road force balancing, I had a vibration that I couldn't get rid of when I had a set of Avon M550 Tech tires swapped from my wagons to thin spokes on the rear. I had them balanced a few times and the problem wouldn't go away. I thought I had bent rims, but just in case I had them road force balanced. They were able to show me that the rims were perfect but the TIRES were out of round. They had to clip weights a the furthest extent of the rim (lead clip style) vs stick on to get the tires even close to usable. Once they did that, the vibration was gone. Unfortunately the tires were just out of warranty by Tire rack (one to many burnouts) so I ended up running them until they were almost bald.

AU N EGL

after market rims tend not to be balanced too well.

vibration at that 80 mph mark tends to one of the following: alignment, tie rod ends, or front bearings need replacing.

I would put my money on the aftermarket rims not balanced wt wise and poor alignment.

Road force balancing or just a normal balancing should do the job. Road force balancing is just another way for some shop to make more money.

Billdog350

AU N EGL, I agree with you 99% of the time, you're a well respected member on this board with lots of real world experience (and seat time on the racetrack). However, I strongly disagree with you on regular balancing vs roadforce. I watched the first shop spin balance the tires twice and they came out 0.00 on the inner and outer when they were done with the stick on weights. However the tires still vibrated, esp at higher speeds. Road force balancing also came out to 0.00 when they were done, but there was no vibration. If you have good quality tires and known good rims, I agree that regular balancing is fine...but if you have unknown rim or tire roundness....road force is the best way to check that out.

AU N EGL

then go for it.

I stopped having my rear tires balanced a while ago. Just mount them.

TexasZ06

Turns out that it is a wheel bearing. Guess I didn't do the wheel bearing test correctly. Thanks for everyone's suggestions.

Skeld

Was it in the back or the front? I feel a vibration in my car on a 2 or 3 second interval, but I feel it mostly in the seat. This is at 70+. I do have a slight wobble in the steering wheel when changing left to right as well.

$$$frumnuttin'

Thanks for letting us know...this explains what I discussed above.

slothy

how did you test it correctly?

TexasZ06

it ended up being both the front and the rear... front was causing the vibration, rear was causing some noise that I was attributing to tire noise having never had a vert before.

TexasZ06

took it to a good mechanic... only so much I can diagnose myself... always just try to help rule some things out so that they don't have to spend as much time diagnosing. Luckily here he recognized it right away.

AU N EGL

I grab the top of the wheel and push it it and pull it out. If there is some movment, then I take the wheel OFF and do it to the bearing.

Change both sides at the same time. If one is gone the other is going.

Not too difficult to do if you are somewhat mechanical. I wasnt at first but learn to do just about everything.

Timkin Bearing from Autozone ( same as GM OEM ) about $180 or so

jpandes

Make sure the rims are not bent. I had this problem. Balanced tire on a bent wheel = vibration

leadax

You do not knoe enough to have commented.

leadax

You do not know enough to have commented.