well i check on wat u said and got them all balanced again he does the dynamic balnce both sides of the rim and has like a sh*t load of those finger adapters ans they blanced out good when he put them on it so when im dont with my onversion i hope the wheel bearing i just reconlent changed will help ill let you no thats for the advice rod

im not really sure
 

did anyone else hear that driving over the recommended speeds on a donut ( the spare tire/wheel) will cause driveline problems especially if its on the opposite side of a larger outter diameter wheel like an 18 with 275s on it. Im theorizing that this would cause premature failure of the differential. Maybe that is what happend to your car, maybe not, if someone has actual facts about this please enlighten me. Thanks.

oh and if you friend has a frame lift put it on there and start your car and run it up through 3rd gear see if you have vibration/ and or hear the clunk...this is a good way to eliminate the tires from the equation. If you don't have vibration when car is off ground then it a suspension problem something is shifting or loose or both. if you have bad vibration when car is lifted than its a drivetrain or wheel problem. Next take off back wheels run car again and you can eliminate wheels from the equation. Have fun,let me know what you find. ( im betting you got a bad differential)

First of all, Running the mini spare can only damage the differential if... You run in it on the rear of the car opposite a tire that is subsatantially taller or shorter (more than 10%) for an extended period of time. Width of the tire or diameter of the wheel itself makes no difference. The only thing that matters is the OVERALL DIAMETER of the wheel/tire combo. You can have a 20 inch wheel with a low profile tire that overall is the exact same "Rolling Radius" as a 16 inch wheel and tire.

This potential damage is caused because one tire needs to complete more revolutions to cover the same distance... so you have one axle turning faster or slower that its counterpart. Again though, this is over an extended period of time. The same "damage" will happen to your diff if you just turn tight circles for a long period of time... the inside wheel will be turning far fewer revolutions that the outer... Understand?

Now, as for lifting the car and running it through the gears to "Eliminate" a tire shake... You HAVE TO REMOVE THE WHEELS FROM THE CAR. An out of round or out of balance wheel/tire will STILL make the whole car shake even if it's off the ground. In fact, it will shake MORE.

Rod.

Hey Rod, thanks
 

for clearing that differnential question up for me, i think the tire combo of 275/35 r18 is the one with the worst differnce in overall diamiter but im not 100% sure on that, that was why i mentioned that as a possible problem. And hey, you never know if someone was dumb enough (previous owner) to run the spare on the back on a long trip at 70mph+ there is a good chance they would have stressed that differential beyond its engineering limits.

also if you read my last post one more time and pay particular attention to the last couple sentances you will realize i mentioned to take the back wheels off and run the car like that to eliminate the possible wheel problem. Restating what i already said doen't make you right and me wrong it just makes us agree. Have a pleasent day :) oh, what tires do you reccomend for the z32, im using Bf goodrich G-force t/a KDW-2s and i love em.

Yokohama AVS dB S2's. great wet or dry, and quiet too. i love them.