Tyre Size for 1998 XJR V8 ---X308.

[prospero]

I would like to fit new tyres size 255x45x18 on my Penta alloy wheels.
Can any member confirm that this size will fit into the wheel arch OK?
What size have members got on their XJR's ?

Thanks for any info.
prospero.

[steveandtina]

should do mines got 255/35/19S ON MOTREAL RIMS

[prospero]

should do mines got 255/35/19S ON MOTREAL RIMS

Thanks Steve and Tina.
I've already got 255x45x18 on the rear,so I think I'll proceed on the front.

prospero.

[joejag308]

Propero..............the only stipulation i can recall is for the supercharged models to have at least 8.50inch wheel width for the larger type calipers
My Daimler super v8 has 235-50-17-ZR on 17" alloy SOLAR wheels as standard........the width is the one to watch...the whell arches are the same its the larger caliper thats the problem ......Joe

[prospero]

Propero..............the only stipulation i can recall is for the supercharged models to have at least 8.50inch wheel width for the larger type calipers
My Daimler super v8 has 235-50-17-ZR on 17" alloy SOLAR wheels as standard........the width is the one to watch...the whell arches are the same its the larger caliper thats the problem ......Joe

Joe,
Thanks for the info.
In view of your point about the size of the caliper,I think I may now
put 235x45x18 on the front.

prospero.

[steveandtina]

why not try rear ones on front then you know for sure?

[prospero]

why not try rear ones on front then you know for sure?

Steve/Tina,
Thanks for your reply.I cannot lift /fit these wheels and tyres ( 225x55 on 16x8 is my absolute maximum lift on my 1990 SL )
myself,so this is another operation for my tyre fitter.
I'll post back when complete.

prospero.

[prospero]

why not try rear ones on front then you know for sure?

Steve/Tina,
Thanks for your reply.I cannot lift /fit these wheels and tyres ( 225x55 on 16x8 is my absolute maximum lift on my 1990 SL )
myself,so this is another operation for my tyre fitter.
I'll post back when complete.

prospero.



Sorry for the delay.
The 225 x 45 I have fitted are OK.

prospero.

[springelec]

Hi All,
I would like to add my question for comment.
My XJR uses 255/40/ZR18 95W tyres and my XK8 uses 255/45/ZR18 99W on the rear wheels. Now I've checked the standards and found the following:

255 = Tyre width (mm)
40 = Aspect Ratio
R18 = Rim Diameter (inches) ???
99W = Load Index
ZR = Speed Rating (186mph)

Two cars use three different tyres which can be reduced to two different tyres if I change the XJR tyres to be the same as the XK8 rear wheels. For those not familiar with XK8/XKR's, the front tyres are narrower, i.e. 245/45/ZR18.

Is there a technical/legal reason why I can't change the XJR tyres for 255/45/ZR18's and reduce my inventory problems ????.

Thanks all

Springelec

[peterch]

I have an uprated XJR (running on LPG) fitted the wider rear XKR rims with 285 35 18 tyres on the back and regular 255 40 18 on the front, with Pirelli P Zero's all round.

I spend most of the time poodling around London so they never get hot and first gear always spins the wheels when pushed.

I rarely go above 70 mph because of average speed cameras, now on the North Circular, and have decided to run softer winter tyres all year round.

The only ones made for 285 35 18 are Dunlop SP Winter Sport 3D. (for real snow I have an old 4wd 2.5L V6 Manual X-type).

[XJ_Driver]

Hi Prospero,

Coincidently both of the XJRs which I have owned were fitted with 19" Apollo (XK8) rims when I bought them (front tyres being 245/40 ZR 19; rears 255/40 ZR 19). As an experiment, with my previous XJR, I once swapped the wheels front to back to see if I could run with the wider '255' tyres on the front. As an experiment it was fine, and there were no clearance issues.

In fact the only problem I found in running such large wheels / tyres was tramlining - especially on the poor road surfaces around our way. Because of this my current 2002 XJR now sits on 17" Celtics and the ride and handling are very much improved!

However, I believe minimum 18" diameter wheels are necessary on the later XJR100 models on account of the larger Brembo brakes.

Hope that helps!

Cheers,
John.