The 03 XJR I have has 20 inch aftermarket wheels. The Jaguar service place I go to has a 98 or 99 parts XJR that I could have bought the 18 inch wheels from. It turns out I can't use them because I have the 'big brakes'. What do they mean by 'big brakes'?

 

It means that you have the 2003 Jaguar XJR R1 model with the upgraded brakes, wheels and suspension.

 

Thanks

 

19" were only fitted to the XJR100 - BBS 'Montreal'. The R1 package as your car has came with 18" BBS 'Milan', generally which fit very nicely over the Brembos.
Both rims are rare as hen's teeth

BBS Milan

 

"R1" package do NOT include upgraded suspension. Just wheels and brakes

 

It sounds like I will eventually have to find aftermarket 18 inch wheels.

 

Or you could downgrade to the standard (non-Brembo) brakes as well? If you're only ever using it for regular road use, you probably won't even notice the slight decrease in performance.

Also, there are usually plenty of people willing to pay very good money for Brembo's and the associated wheels so they can upgrade. You'd probably make a nice profit from the whole thing, and get a more comfortable ride while you're at it.

Do you have a pic of the wheels currently on your car?

 

This is my 03 XJR with the 20 inch wheels. I'd rather have the 18 or 19 inch wheels.

 

18's look a little small on these cars. I would go with some 19's that look close to one of the factory options

 

18's can look fine, like the factory XJR 18's, but I do kind of agree when it comes to the Milans. Something about the spokes sticking out like they do makes them look undersized for the car.
19's are a nice modern looking alternative. Although, you might have more luck going with aftermarket 18's instead. Plus they'll probably be cheaper than finding genuine Jaguar BBS wheels.

 

the nice thing with the Milan, being 18', is that they make the "R1" calipers and rotors look HUGE

 

I called the San Diego Jaguar dealer's parts department today to ask them about what sized wheels came with my XJR. I gave them the last 5 #'s of my VIN. You were correct when you said it came with 18 inch BBS Milan wheels. The dealer also said my XJR did come with an upgraded suspension. The Jaguar service place I go to told me the shocks and struts are still the regular kind and not the electronic kind.

 

Ohhhh???

 

Steve
In the US, The 02/03 XJR came stock with the CATS ( Computer Active technology Suspension)
Prior years (98 to 01) did not
Just open the hood and look at the top of the shock , do you have a wiring with a plug or not?
if yes, you have CATS, if not, you don't

 

These are big cars, 19's fill them out much better IMO

 

If I kept the 20 inch wheels and switched from the 245-35-20 tires that are on there now to 255-35-20 sized tires would there be enough lateral room for the front tires to turn without hitting anything?

 

i found out the 255-35-20's won't fit.

 

IT'd be (very) tight, but they should. Have you looked into rolling your guards?

Of course, this all depends on the offset of your wheels. The lower the offset, the closer they'll be to rubbing the outer guards

 

If I look at your pictures, and see the right front fender, seems you got the problem already, you hooked the lip.
So going bigger will only make it worse.

 

I would never get bigger wheels. Only 18 or 19 inch wheels. I can't even afford it now so maybe some other time.