I have had my xkr a few weeks now and had noticed a strange rattling sound when setting off, it didn't seem to be related to the engine speed so put it down to a brake or suspension issue.
After trying myself to find what the noise was I couldn't find anything untoward so took the car into my local independant to see if they could sort it.
From inside the car the rattle sounded to be coming from the front nearside wheel area, so off came that wheel, brakes dismantled, suspension checked, no issues found so back together it goes. They took the car out and the rattle was still there, so one of the guys drove it slowly while the other walked along side to listen where the rattle was and found it was actually coming from the rear wheel area, so off with the wheel, brakes dismantled, suspension checked, all ok, so they were puzzled and getting frustrated. With the car up in the air one of the guys just happened to spin the rear wheel and the rattle appeared and actually sounded to be coming from inside the tyre!? The tyre came off and inside the tyre they found a 10mm ball bearing! Obviously got in there in the tyre bay prior to fitting.
At speed the ball would have been held against the inside of the tyre by centrifugal force but when moving slowly it was rolling around and falling from one side to the other.
Problem solved but who would have suspected that?

 

Strangest tire noise episode I have ever heard. Good detective work in finding the problem. Happy motoring....

 

During my career at sea the accommodation deckheads (ceilings) were underhung with sheet metal sections (similar to a drop-ceiling). It was certainly
not unknown for shipyard workers to leave screws behind, usually in the most awkward places, which would then start rolling around with the motion
of the ship. Not much fun trying to find the culprits at 2a.m. so you could catch some undisturbed sleep!