First, best I can tell the aggregate permissible hub and rotor runout is 0.1 thousandths. Someone please feel free to correct me if I am wrong.

I ask because I replaced my aging tires not once but twice when the first shop couldn’t eliminate post-install vibration and told me chances were good it would go away if I replaced pads and rotors, particularly rear stuff. I took the car to the mother ship of this firm, considered locally to be the creme-de-la-creme of tire knowledge because I could feel no brake pedal pulsing before or after the first set were installed. Finding an out-of-round tire up front on the first brand, the mother ship pros checked all five I bought (spare too), then checked their inventory, and pronounced the first brand entirely flawed because of unevenness in the joints of multiple tread pieces on each tire, including what they had on hand. Next came a second well-known brand and lots of careful road-force balancing, on-car spinning, etc.

Vibrations are quite substantially reduced to a slight frame buzz and a background vibe on the steering wheel. The car is quite driveable. But I can’t help but wonder if I still need to get someone to check tat least the rear rotors and hubs for runout. I’m embarrassed to think my assumption that not feeling vibrations or brake pulsing before new tires went on was a make-work project for a number of folks based on my substantial ignorance and assumption I knew more than the professionals about Jags. On the positive side, everyone at the mother ship busted their backsides to sort this out and asked only that I cover the increase in their cost of the new set of tires. Great folks.

Side note: inexpensive scanner arrives tomorrow so I can reset two misfire and one cat-converter code to see if they’ll stay gone. I presume if those codes return I need to replace at least coils and plugs, hopefully not a cat! I think I actually could do the coil/plugs job myself.

 

Hub should not have any runout at all. In metric scale 0.01mm should be absolut maximum. New hub is 0.00mm. If hub is warped like 0.02mm. Then disc measured from outer edge of the friction surface the disc is easily warped 0.05mm or more. 0.05mm can be felt.
Rust in the surface will cause vibration to the measure. Then the correct measure is somewhere in between oscillation maximum.

 

If it’s vibration you are chasing then I found on my X300 that changing the gearbox mount and centre prop shaft bearing made a huge difference.

 

Thanks to you and Vauxi for your education. At the first shop we saw a fractional amount of side-to-side movement in the driveshaft and the manager mentioned a lip on the rear discs. Once I get past some things twixt now and mid-October I think I'll book the car in at our local British car shop and ask them to assess the undercarriage health from motor mounts back to the rear shocks, bushings and subframe stuff and map out a plan of attack..

If it turns out the issue was absolutely not tire related I suspect I'll owe an apology to the founder of the tire company who personally invested considerable time working the issue for me and upgrading the product asking me only for his cost. The frustrating part is I didn't feel anything wrong before I went to replace the tires, but I would guess old tires might obscure other issues.

 

the only way to stop repeat brake vibration offenders is with a procut