7.30.3 - Tire speed rating ( ,  December 3, 2001 )

That's another common question on the Modern List where many people wonder if they could replace their higher speed rating tires with less expensive tires having lower speed ratings. The argument often given is that they will never drive their cars over a certain speed so they don't see why they need to pay for the extra performance.
P=93 MPH / 150km/h H=130 MPH / 210km/h
Q=99 MPH / 160km/h V=149 MPH / 240km/h
R=106 MPH / 170km/h Z=over 149 MPH / 240km/h and over
S=112 MPH / 180km/h W=168 MPH / 270km/h Cars
T=118 MPH / 190km/h Y=186 MPH / 300km/h
U=124 MPH / 200km/h

87 thru 92 models came with V rated tires and all others came with Z rated tires; indeed most of us will never get to enjoy pushing our cars near their design limits.

However, while saving a couple of hundred dollars is tempting, other factors play a role in tire selection such as weight and heat. Modern Jaguars are heavy cars and even at medium speed this will contribute to the amount of heat generated. The higher speed rating provides an extra margin of safety lower rated tires might not.

In addition to this, modern manufacturers often tune the car's suspension for a specific type of tires and unless you absolutely need to save money on tires, sticking to the original model, size and rating is a safe way to go.

Below is of tires fitted by Jaguar for various models, along with alternatives list members have had good experience with. Obviously, their needs could be different from yours and as often said... your mileage may vary...

Year - Model Size Model
87 - 92 XJ6 205-70VR15 Pirelli P5 (discontinued )
93 XJ6 225-65ZR15 Pirelli P4000E
94 XJ6 225-65ZR16 Pirelli P4000E
94 XJ12 225-60ZR16 Pirelli P4000E
95+ XJ6 225-60ZR16 Pirelli P4000E
95+ XJR 255-45ZR17 Pirelli PZeros

Note that there is difference between the cheaper P4000 and the P4000 E which was original equipment and much better than the first one.