I've been researching winter wheel/tire combinations for my soon-to-be-delivered 2011 XJL SS and found threads wherein posters warned that there is a possible difference in brake caliper size between normally aspirated new XJ's and SC / SS models.

Can anyone confirm and/or indicate the difference (if any)? Thanks!

 

I don't have definitive proof, but it has been reported here that a N/A XJ could fit an 18" wheel while on my own car, based on my measurements, the smallest wheel that would fit would be a 19" due to the size of the calipers.

A quick check of the parts catalog indicates different part #s for supercharged vs. normally aspirated vehicles too.

 

NA XJs have one piston on each wheel, where SC model has two pistons per wheel.

I will try to see if i can find some numbers.

 

Very interesting. Thanks. Until I take delivery of my car (...just a few more days...), I have nothing to look at to verify and/or compare.

I'd really appreciate those numbers if you manage to find them.