XJS HE Tyres
Follow this link to actually buy the tyres for your Jaguar XJS.
Towards the end of production of the pre HE Jaguar XJS, Jaguar started to take advantage of the new Pirelli P5 tyre that Pirelli and Jaguar had developed between them. The 6 cylinder XJS fitting the 205/70 WR 15 PIRELLI CINTURATO P5 and the XJS V12 fitting 215/70 WR 15 PIRELLI CINTURATO P5. Both these tyres are being produced again by Pirelli for the XJS, and have been homologated by Jaguar with a J. They are both also W speed rated.
Jaguar XJS HE 235/60 R15 Tyres
At the very end of the 1980s the various models of XJS HE Jaguar started moving over to fitting the 235/60VR15 Pirelli P600 tyres. These tyres were only fitted to the XJS for a few years as they soon moved onto fitting 16” wheels. The 16” wheels are very much a fashion thing. They will not, of course, offer as much comfort as a 15” wheel, as you have lost ½” of the sidewall with which to absorb vibration and the shocks of the road.
235/60 R15 P600 XJS V12 HE Tyres
Jaguar XJS on 235/60 VR 15 PIRELLI P600 Tyres
Great News for later XJS and XJR-S owners is that Pirelli are making the 235/60 R15 P600 tyre again.
There is a perception, with the XJS HE models that fitting a 225/60R15 tyre is an acceptable alternative. However there are several issues:
1. It is a bit thinner.
2. It is the wrong diameter.
3. It will affect the speedometer.
4. It is a modern carcass design.
This isn't so much of a problem. Earlier XJS's fitted 205 section tyres and 215 on the V12. When they sacrificed the ride a little and moved onto a 16" wheels they went down to a 225 section again, so the width thing isn't too much of a problem.
Actually if you were going to be critical of an XJ-S HE, possibly the fuel consumption would be a valid starting point. having a smaller circumference tyre will only make fuel economy worse.
The speedo will be a bit out of whack.
The car will be lower, moving your exhaust pipe closer to speed bumps etc. Do you want your XJ-S HE lower?
A little bit less side wall height will give a slightly harsher ride.
If you want to go looking into diameters, the listed diameters i have for their OE tyres are 205/70R15 P5 675mm, 215/70R15 P5 685mm and then the 235/60WR15 P600 lists a diameter of 689mm.
Modern Carcass design
Pirelli P600 Tyre
This is the truly critical thing.
Jag didn't just guess that the 235/60R15 P600 was a good tyre for the XJ-S HE. The P600 wasn't chosen just because Jaguar thought the tread pattern was pretty. Pirelli and Jaguar have a long history of working together to subtly tune the tyre to suit a car. They were OE because they work best on that XJS. Its not just guess work. When Jaguar moved the later XJ-S HE to the 16" wheels they would have subtly tuned the chassis set-up to suit the new wheel and tyre combination. These developments compliment one another.
The geometry and suspension of modern cars is different from when the XJ-S HE was built. Yes, the modern tyre carcass gives better performance on a modern car's chassis set-up because they are designed to compliment that environment. However, a modern tyre does not suit an old chassis geometry, such as the chassis of a Jaguar XJ-S HE. Modern cars have more caster, more negative camber and stiffer springs. The handling and ride drawbacks of these features are overcome by the modern, much cleverer power steering and computer controlled suspension that an XJ-S HE does not have.
I realise that a lot of XJ-S HE owners will have bought their cars in the glory days; in that period where they were cheap as chips. Lets face it, a Jaguar XJS got outrageously cheap. At one point I would assume they were probably the 'most car you could buy for the least money'. However, what you pay for a tyre isn't relative to what you paid for the car, especially something like an XJS. It was an epic car that ended up being too cheap. What you pay for a tyre is related to the quality, specification, and, unfortunately, a big contributor is batch size. A 235/60R15 tyre only truly fits a few years of XJS and the rear of a DeLorean (that I know about), and this makes the cost mount up. The 235/60WR15 P600 is not expensive for what it is, but i cannot argue that it doesn't add up to a large credit card bill. But one of the reasons that the values of XJS got so low in the first place is because they are not cheap to run.
I know it is not what people want to hear, but the good news is that for people who really do want their late 1980s - mid 1990s XJS to handle at its best and choose their tyres based on what is best, they can at least get the right thing.
Originally it was 205/70VR15 Pirelli Cinturato P5. In 1987 they moved to 235/60R15 Pirelli P600 up until 1991 when Jaguar gave their XJ-S He a refresh and facelift.