Advice please regarding tyre pressures. The handbook says 32 - 34 pounds/square inch for my vehicle, but for tyres other than those recommended this should be 44. This seems a very high figure, so should I follow this advice as I don't have the recommended tyres on my car or stick to the lower numbers?
Thanks.

 

An earlier thread Tyre Pressure for Maximum Comfort has a copy of the following sticker for every one's ease of reference:



Look at your tires when pumped to Jaguar's recommended pressure, if it is still a bit flat (this would cause more tire wear at the margins) go up by 2 - 5 PSI. The common choices are 32 front and 36 rear.

 

I got those numbers from the Vehicle Care handbook and they refer to "Normal Pressures" front & rear. There are also the pressures as in your post for "Maximum Comfort" in my handbook which are the same as in your post.
BUT it does say in the table you posted "For tyres without Jaguar approval: Refer to Handbook". That is what I was asking about. I don't have the recommended makes of tyre fitted to my car, in which case the handbook says I should inflate to 44 pounds/square inch front and rear. It is this figure I was asking about as it seems rather high but if it's what I should be doing then it's okay I guess.
Thanks for your response.

 

We can only speculate as to why such a high pressure would be recommended. It certainly sounds arbitrary.

Higher pressure is generally consider safer. Perhaps Jaguar assumed *any* non-recommended tire would be the wrong load rating or be low quality... and thus recommended the high pressure as a safety buffer? I dunno.

FWIW I ran an X300/XJR for many years and used several types of tires. I experimented with pressures in the 30-35 psi range until I found what felt best for me.

I would think that 44 psi would result in poor tread wear.

What specification tires are you running?

Cheers
DD

 

Hi Doug, thanks. I'm using Michelin Pimacey HP tires 225/60R16. Three makes are recommended in the Handbook including Michelin Pilot CX-KA.
Always inflated to "Normal" pressures as in the book, but just wondered because I haven't got the exact recommended tires, perhaps I should inflate to the higher pressure. Have tried it a couple of times but thought they were too hard, so confused because it appears Jaguar are recommending this pressure of 44 pounds/square inch for non-recommended tires!

 

biffta, I ran those tires (tyres-same make/size) at 34psi for 80K miles. Wet traction got dicey about 60k, which was the warranty, but even at 80k I still had more than 2/32" tread depth. However, by then they were just too slick in the rain despite plenty of tread remaining.

I've switched to Michelin's "Premier" now....

 

Running 44 psi is unusual for this type of car, and Jaguar apparently doesn't explain *why* 44 psi is recommended.

Whenever I lack full information or explanation I always go with what seems normal, rational, customary, and makes good common sense to me. If someone is telling me to do something unconventional I'm not likely to do so without being given a good reason. That's just me

When a car builder recommends anything they certainly face numerous considerations....not the least of which is easiest and safest for THEM. Jaguar is not in a position to evaluate every tire on the market so an arbitrary recommendation of 44 psi works best for them.

Might not be the best for the consumer, however !

Cheers
DD

 

Thanks for that, I don't do much mileage, but oddly enough I've found them not good in the wet. Live in Spain, so not a huge problem, but when it rains it does rain but fortunately I have the luxury of being able to choose not to use the in car bad conditions.
Thanks again.

 

As always Doug, wise advice.
Thanks.

 

tyrepressure advice is to give te tyre a deflection for te max speed used, that wont overheat any part of tire . Higher speed lesser deflection so higher pressure for same load on tyre.
The tyremakers calculate te maximum load of a standardload tyre for 160km/99m /h. And the reverence pressure of 2.5 bar/36 psi in eur system.

To be short , give tyre data and weight on seperate tyres or axles and speed you wont go over for even a minute in your use, and this selfdeclared tyrepressure specialist will calc the needed pressure.