Hello All,
Thought I would pass on my findings as it may be helpful. Recently purchased an 06 XJR with 41K on the ODO. Being perhaps too meticulous I set out to take care of a few minor items. One area that I could not figure out was at times an unusual vibration. I say unusual because depending on temperature, ascending or descending hills and speed it would at times be present and other times not.

My first thought was tire balancing, second was u joints, differential etc. I was planning on having the road rash removed from the 20" Sepangs at a shop in Renton WA called Dependable Wheel Repair (excellent job on the rims btw, look new). Upon pulling the rims off and inspecting he noticed within 30 seconds I had a wheel out of round. What seemed to be the size of half of a golf ball dent on the inner side of the rim. Within 2 hours all rims were restored and the problem rim was straightened.

What's interesting is the out of round rim and tire WAS NOT OUT OF BALANCE. To this point Tim said you can balance a football, but that doesn't mean it will roll smoothly.

Now it rides as smooth as silk with no vibration at any speed! Due to the low profile tires and size of these rims, any issue such as what I had will manifest itself in some form of vibration. So for those of you that might have experienced something similar I would look at the very basics first.

Now on to my last task, I have a squeak in the dash that appears to be coming from behind the wood trim around the analog clock......

 

Thanks for sharing. I have a mild vibration in my 06 too and am hoping it is tire/ wheel related (as opposed to a diff. issue). Glad you had a relatively painless fix.

 

Yup, they can try 'balancing' it w/ weights, but that kind of damage can't be hidden at all speeds. Good find, and be careful around those potholes.