1968 130 Sedan

The car has started to pull left and vibrates at speed, overall ride is rougher, tires seem to cause a lot of road noise (even before).

Background
The extra road noise has been with me since at least July (when I swapped for the newer tires from my 65 project car).

I was worried the noise was wheel bearings failing so I pulled and re-packed the front and squeezed as much new grease into the rear bearings as I could without pulling the axles. The "bearing" noise persisted - especially from the the front even after I swapped the front crossmember and rotors.

a couple weeks ago, I decided that it might be the tires themselves so I put my worn kumhos back on the sedan. It solved the noise (mostly) but suddenly the car would shake horribly at highway speeds. Out of balance (I figured) so I put the newer 65 wheels back on the car over the holiday weekend.

Here's where it gets weird. The old road noise is back, but the car now strongly pulls left and I still get vibration at speed. Neither were an issue with these same wheels before. The "pull" is really worrying me. I put the car up on jacks last night and checked over the wheels and suspension - nothing seems to have changed, nothing has loosened up, yet the car now handles poorly.

I seem to recall reading something about switching radial tires around being bad, but this seems way beyond that. There's no evidence of brake binding pads are good, front wheels spin soothly. I have newer SS brake lines and a new SS clutch line as well as poly endlink bushings and poly steering shaft bushings.

It's probably unrelated, but the handling has gotten to be generally poor. The bushings are good all the way around, but the ride now seems very harsh. Maybe part of this is the old shocks - the car does not bounce excessively - but I'm not sure what the failure mode of shock absorbers feels like. The muffler will also knock loudly against the body when I go over bumps. The muffler "suspension" was also checked and found to be in good shape. The muffler is a skandix kit that's only a year or so old.

Any thoughts or ideas here are appreciated.

Well it's a good thing you replaced the clutch hydraulic line... that was my first guess :-)

I gotta agree with Derek... you changed tires and things changed. then you changed them back and things changed for a third time. When you changed back, did you put the tires on the same corners of the car? Or might you have swapped left for right?

How old are all the tires (in years)? Sure sounds to me like out of round/tread separation situation. Don't go anywhere fast until you've got it worked out. Could be tread separation, and that could be caused by some other issue with the steering.. alignment, etc.

--
-Matt I ♥ my ♂

Sounds like your tyres are out of round and/or out of balance. If you say the older Kuhmos are quieter/better try mix and matching them in axle pairs or as singles to see how that changes things. You can rig up something to check the runout on the wheels and tyres but they really need spinning up on a machine by someone who has a bit of time to check them out properly. Vibration through the steering is usually the fronts and drumming through the body the rears. Some people never bother to get the rears balanced but it can transform the way the car feels if there is a balance problem. Can't comment about the pull to the left but swapping the fronts right to left might change things.