Remeber the BMWs of that era was not made for off the line rockets in a sense. The gears was very tall and even the new 3 series probably would smoke one off the line and made as high speed autobahn cruiser. But for some sort of gentleman agreement between German makers and insurance, and etc it was limited to 155mph and most german cars of that day and today. Even the 560SEL ( big heavy block of metal that probably could be driven through a brick wall with no personal injuries) have reach 150 mph ( with a designed that was done in 1975) I know this personally as I've done it on the autobahn and it still felt like an average car cruising at 100mph. So it's not farfecthed on the BMW v-12, which is suppose to be more sporty than the Stuffy stodgy MBZ, could reach 185. plus many articles on this feat. as this was one of the cars that gave rise to the 155mph limit of European car makers.


But granted that proper tires for these type of top speed runs are a dime a dozen in Germany, where the all-season tires are actually relatively rare on the market (usually either have summer tires or winter) I could hardly find tires below Z-rated tires for stock rim sized MBZ 560sel but I equipped the car with Y-rated tires for the top speed run on the autobahn.

 

I have not stretched the legs on the XJR quite yet. Only 120mph so far. Had plenty of RPM and rolling torque to go. Would love to find out!