Since owning my Conv., there has always been an issue with vibrations. Not to the point of not wanting to drive, but just an annoying "I need to have this fixed" sort of thing.
The best balancing machine (IMO) on the market is the HUNTER Road Force machine, but the place I had my XJ8 balanced said their machine needed service, so I've put it off. Talking to a friend, he told me to check this other tire place and sure enough they had a Hunter.
If you don't know, the Hunter machine does all kinds of things, such as; checking the wheel for damage & out of round, tells the operator if the tire needs to be repositioned on the wheel, simulates road conditions--by applying a heavy roller against the tire while it is rotated (1200 #)-- and oh yes, balances the wheel and tire and tells the operator if the weights need to be on the outer inboard lip or inside the rim. Nothing ever is on the outside of the wheel on our alloy wheels.
All our cars have very wide tires on them and if a tire outfit doesn't have a HUNTER Road Force machine or one like it, I'd go elsewhere, or at least take the car with the new tires to a place that does.
Anyway, had it done today and car is as smooth as a babys bottom. Cost? 15.99 a wheel.

Chuck
05/XK8 Conv.

 

Agreed. When my wife's XK8 gets new tires, I always have them Hunter Road Force Balanced. I learned the first time I put new rubber on the rear axle that if this is not done, the car will pull either left or right. I purchase all our tires at Discount Tire and as long as I specify that this particular car needs the Hunter system each time the tires are replaced or need balancing, they do not charge me for the service....

 

And never be surprised when you buy new tires and have one come up with higher than spec'd road force from out of roundness. But you have to specify to run the road force portion as you can also use it as a regular balancer