Hello Forum, I am considering new wheels for my 2003 XKR. The existing tires are Rear: 255/45R18; Front 245/45R18. My question is "what size wheels do I need?". I pulled one of the rear wheels today to see if I could find some type of size indicator.

Here is an image. Does this code "9.0JX18CHX35.0" mean anything to anyone?




Thanks for any help!

 

9 inches wide x 18 inches in diameter and a 35 mm offset.

*Not entirely sure if that 35 is offset, backspacing, or something else mot all I sure about that unit of measurement.


Your front wheels are 1 inch slimmer in width.

 

For Jaguar wheels, the sizes are listed on a sticker under the arm rest. Unless you have the Brembo brakes, I believe all X100 sizes fit just fine. For Brembo brakes, the big exception is the 19" Apollo, but normally 19" and above fit. Some 18" fit as well (Hydra).

For after market, there is size (18" in the formula above) and width (9" above for the rear, front are 8"), but also offset (35mm), bolt pattern and size of the hub. The bolts press the wheel on the hub, but the weight of the car normally rests on this hub ring. You also have to keep in mind that deviating from the original tire diameter will translate directly to the speedometer, so the normal recommendation is to keep it well under 10%. Last, the ABS computer "knows" your rolling diameter front and back, so you have to stay within that front and back with the new setup. You can find online "tire calculators" to help with this.

 

Fmertz - surely the smaller wheel with fatter tyres will have the same (or at least, very similar) overall diameter as the bigger wheel with low profile tyres?

 

Sure, as long as one stays with the combinations outlined on said sticker...

 

I have identified the size of the wheels that are now on the car. Front:8.0 x 18, with 33mm offset; Rear 9.0 x 18, with 35mm offset. I believe the name of the wheel is Hydra. The car does have Brembo brakes. I like the Coventry Whitleys, but I can't seem to find identical replacements.

 

Check that the space saver spare wheel fits, as there is an (outside) chance that it is a non-brembo spare, in which case you would not be able to use it.

 

I believe a few members of this forum have installed Coventry wheels on their cars. There is likely no need to have IDENTICAL measurements for wheels to fit. Reach out to Coventry, I am pretty sure they have done this before and can give you pro advice.

 

Thanks fmertz. I'll do that.

 

Good idea Diddion. I did check, and the space saver wheel fits on both the front and the rear.