CV joint grease in the cold?

[ohecht]

My 82 SC has a very slight rythmic vibration feeling during the colder mornings here in Richmond. It feels like a speed-sensitive, slight thumping.

I have checked everything around the wheels, which have new bearings, and the lug nuts are tight.

What is perplexing is that it goes away as the car warms up, which leads me to think it is either in the transmission or the CV joints. Neutral or putting in the clutch does not seem to change it.

One theory I have is that the grease in the CV joints, when cold, doesn't "flow" well and perhaps rides in one side of the joint, causing the slight imbalanced feeling. Once the grease warms up from the friction, the grease "evens out".

Has anyone ever heard of this happening, had it happen to them, or know of something else I should check?

Thanks,

Olivier

[nhromyak]

What kind of tires do you have?

Sounds like the tires are flat spotting. My Yokos did this overnight.

[ohecht]

I hadn't thought of that,

the tires are Bridgestone Potenza RE71s

Are certain brands more prone to that happening?

Olivier

[nhromyak]

Are the tires fairly new?

I think this happens to the softer compound tires. The RE71s are a fairly hard compound.

I don't recall my RE71s doing that. I have the RE730s now. I have not really noticed this happening lately. I guess it happens for a little bit, but nothing that I have been noticing on a regular basis.

For peace of mind, I would check the CV joints. Usually these will click and not thump, unless maybe the CV bolts are loose.

Have these recently been serviced (taken off and inspected)?

If so, the bolts should be checked for torque.

But then again, why would it go away when it warms up....?

I will pay close attention to my ride early in the morning, (~29 degrees here) and see if I notice the thumping on the 730s.

[ohecht]

The tires are about 4 years old, but only about 13k miles.

Nothing in the drivetrain has been repaired recently. I did the front wheel bearings last year.

It has not been that cold here in Richmond, maybe in the 40s, so I think it must be some mechanical component "warming up".

I will probably repack the CV joints this spring as regular maintenance anyway. The driveshafts have been tight every time I check them while I'm under the car.

Olivier