JayVee

I also noticed that you just had new tires mounted. Here's what happened to my car. I had vibes at speed, so I brought in the wheels to get balanced. The shop showed me that the rims were bent, so I had them refurbed at RimPro. Vibes were gone for months. I hit a pothole that bubbled a tire sidewall, and since the tires were well-worn I put on four new tires. Vibes at speed again. I brought the rims back to RimPro and they checked them. They weren't bent, but all four wheels were out of balance even though the tire shop I went to "balanced" them. Vibes are gone again. At RimPro they showed me that one tire was slightly flat-spotted, but not so much to cause vibes. They did say that they see a lot of flat-spotted tires from sitting a long time in warehouses, and these tires get rounder as they are used. I'd recommend bringing all four wheels to a different shop to check for bent rims, tire balance, and flat-spotted tires.

John_AZ

Appreciate the info. I reread the posts and no one has mentioned the position of the wheel lock. Should be opposite of the tire valve. Minor step but may help. Have you done any major repair work recently? Clutch disk or transaxle work?.

John_AZ

AR10

Wheel lock position?

Now that`s hillarious!

John_AZ

AR10,
Dear Sir,
By your avatar I can see you are an intelligent man with a rifle and scope.
Further explanation:

07-11-2007, 11:26 PM #10
Lizard944
Addict
Rennlist Member
Join Date: Aug 2001
Location: Erie, PA
Posts: 224

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Several years ago, a small "think-tank" of Rennlisters formed to try and finally solve this phenomenon. A common link seemed to be that when people placed the locking lug nut (which weighs more than the other lugs) on the stud closest to the valve stem, that this was just enough weight imbalance to throw off the wheel balance at higher speeds. Solution was to either replace locking lugs with non-locking, or relocate locking lugs to one of the studs on the opposite side of the wheel, away from the valve stem. This way, the valve stem and locking lug "counter-balance" each other. The intermittence of this "shake" seems to come from the wheels occasionally becoming
synchronized in a way that cancels out the imbalance. As the wheels slowly fall out of this "synchronization" while driving, the shake will present itself again.(harmonics)
Clear as mud now?
__________________
'86 944na
Metallic Graphite
No traces of rice

John_AZ

AR10

I am a retired ASE certified mechanic and I still own a high end wheel balancer. If the wheels
are balanced correctly, it would not matter where you put the lock, it would still effect the balance
if was possible, which it is not. The weight of the lock and the closeness to the wheel center will
have no effect on balance.

AR10

Also, do some research on "static" and "dynamic" balancing and you will find out what
causes the "synchronous" vibration you are referring to.
Basically, it is two wheels not balanced dynamicaly that go in and out of phase
as their positions to each other change as they roll. (Due to steering or road slip)

Hope this helps.

John_AZ

AR10,

Yes, thank you.

On the tire mounting procedure, my new Toyo Proxies have a small yellow circle by the rim and they were mounted with the valve stem alligned to the yellow circle. Is this common that the manufacturer wants the stem by the yellow circle? Why does it matter?

And finally, if worn out or inexpensive shocks are used-KYB for instance, do they have the inner damping to prevent a wheel to feel out of balance at high speed? I am not focusing on a soft or spongy ride. I do not think a wornout or inexpensive shock can stop a harmonic, gravitational, or forced what ever its called, tire to stop vibrating at high speeds even if it was balanced on a 5 lug machine down to 1/8 of an ounce. Thus, that is why I thought shocks may be involved.

Thank you again and I did review your profile prior to posting and noticed you were a retired auto mechanic.

John_AZ

AR10

The yellow circle notes the lightest part of the tire as manufactured so putting it
by the stem makes balancing slightly easier and reduces changes as the tire wears.
Tires also should be rebalanced after about 500 to 1000 mi.

ccaarmerciill

The tire shop I got the tires put on, balanced, and aligned, is actually called "tire pro" and that's actually all they really do. So I'm almost positive its not the tires or balancing, I'll get my wheels checked tomorow for being bent, on my x country trip i hit alot of horrible pot holes that i couldn't avoid. And the twists are replicas... so who knows how great the quality really is. I do know my clutch is starting to slip, and my transmission makes a loud humming noise that is slowly getting worse so it could be the differential. If thats the case, I'm not worried as soon as the weather warms up I'm doing a clutch job and I currently have a S2 transmission in the garage awaiting "installation"... Hopefully it all works out. Also I'v been noticeig the car moves around a little at high speeds, it doesnt want to go in a straight line but doesnt pull in any general direction, it just feels extremly sloppy when it hits a dip or goes over a bump at highway speeds. So it looks like I have alot on my hands, but i sort of expected it after a x-country trip.