Severe vibration 40-45 mph. Need ideas.
04-20-2017, 08:26 PM
#16
Race Car
Thread Starter
Originally Posted by -nick
Another idea. For the heck of it, lift the e-brake a little and see if that has any effect. It would at least load up the rear wheels in isolation from the front.
04-21-2017, 10:15 PM
#18
Race Car
Thread Starter
Brand new kwv3. They shouldn't be the issue. Clearly any noise or vibration I have will be transferred to the chassis through the monoballs, but the noise isn't the kw...or at least I think it's not.
04-22-2017, 05:07 PM
#19
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Lift the car up, either with a 2-post lift or by placing it on 4 axle stands, one on each jacking point. Run the car up to 45mph and see which corner is trying to jump off the lift......
04-22-2017, 06:07 PM
#20
Burning Brakes
If distinct noise that accompanies vibration, hookup a chassis ear type setup to various spots then do 9M type test... just no effective movement on coilovers in that type of test 
. Although, if no vibration under that test, it could suggest coilovers..
. Although, if no vibration under that test, it could suggest coilovers..
06-29-2021, 10:56 AM
#23
IHI KING!
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So- driving along, no vibrations , or very limited, until approx 40mph and then severe vibration btw 40-45 mph. Then vibrations lessen as I travel above 45...
This happened with three different sets of wheels and tires. I thought all winter it was my snows, but I just changed to conti dw summer tires and it's as bad or worse on the summers. They are brand new. So still soft.
I thought maybe it was wheel bearings in the rear, so I took out my rear axles today. Wheel bearings are fine (new last summer). One axle has a tiny bit of play in the outer CV, but both were rebuilt by cv of Ocala last summer and they gave me a clean bill of health when they rebuilt them. I thought maybe a bent or out of round rotor, so I switched my rear rotors to my old set of sebro rotors that are like new. I had a function first transmission mount stiffener in, and took that out. Noise and vibration are still present.
Noise and vibration are the same at 45 mph with the brakes depressed. Noise and vibration are the same if the clutch is in and the car is idling at 45 mph. Noise and vibration are the same on varying road surfaces.
Tomorrow I'm taking the front axles out to check them. But I just can't get a handle on what this could be.
I had thought for a moment maybe it's the planetary gear, but that wouldn't be a frequency issue - i.e. My guess would be that if the planetary gear were going I would have vibration and noise through the entire speed range. And not just severe vibration at 45mph.
Anyone have any thoughts or similar experience?
This happened with three different sets of wheels and tires. I thought all winter it was my snows, but I just changed to conti dw summer tires and it's as bad or worse on the summers. They are brand new. So still soft.
I thought maybe it was wheel bearings in the rear, so I took out my rear axles today. Wheel bearings are fine (new last summer). One axle has a tiny bit of play in the outer CV, but both were rebuilt by cv of Ocala last summer and they gave me a clean bill of health when they rebuilt them. I thought maybe a bent or out of round rotor, so I switched my rear rotors to my old set of sebro rotors that are like new. I had a function first transmission mount stiffener in, and took that out. Noise and vibration are still present.
Noise and vibration are the same at 45 mph with the brakes depressed. Noise and vibration are the same if the clutch is in and the car is idling at 45 mph. Noise and vibration are the same on varying road surfaces.
Tomorrow I'm taking the front axles out to check them. But I just can't get a handle on what this could be.
I had thought for a moment maybe it's the planetary gear, but that wouldn't be a frequency issue - i.e. My guess would be that if the planetary gear were going I would have vibration and noise through the entire speed range. And not just severe vibration at 45mph.
Anyone have any thoughts or similar experience?
06-29-2021, 07:32 PM
#24
Rennlist Member
Interesting, I haven chasing some strange grinding noise with a little vibration.
Did you all check your calipers for a stuck piston? Could a stuck pad create that much vibration?
Did you all check your calipers for a stuck piston? Could a stuck pad create that much vibration?
06-30-2021, 12:42 AM
#25
Race Car
Thread Starter
Rob- it ended up being a wheel bearing.
I don't know if *** has gotten their act together with bearing production quality- but back then many were still being delivered without grease, so even though they were new, they went bad quickly.
I don't know if *** has gotten their act together with bearing production quality- but back then many were still being delivered without grease, so even though they were new, they went bad quickly.