Thanks for the input Muenster

 

Thanks everyone for the advice /help , just need to get a set of winter tyres now and put them on the spare set of alloys

 

You will also find that if you use the higher quoted pressure for normal driving the ride will be very harsh, I maintain the quoted 31psi and enjoy good ride and handling, never go over 100mph so only use the higher pressures when fully laden. Phil

 

Watch your tire pressures as winter approaches. You'll have to add air to maintain that 31psi as regular ambient temperatures drop. Your measured tire pressure will drop 1psi for each 5 degrees C.

 

Thanks everyone...thought I was going a bit mad when I read the tyre pressure label , I don't go over a100mph ( well not to often ) so will just stick with 31 psi for now and see how things go.

Thanks

Tommy

 

Higher tire pressure is recommended for high speed operation always. Higher pressure reduces sidewall flex which is the main source of tire heating.

ALWAYS increase tire pressure for full load or high speed operation on any car.

 

The XF is my first "performance" car so to speak, but I have owned other cars capable of more than 200 km/h, which I think is pretty quick. None of them had any remarks in their manuals about increasing the tyre pressure when driving fast. On the other hand, as far as I remember Jaguar doesn't mention anything about using higher tyre pressure when the car is fully loaded. I have always found this discrepancy a little strange.

In general, I'm thinking like you, so when I'm driving with passengers and luggage, I use the high pressure, even though I only drive 130 km/h. I don't think something magic happens at 160 km/h (100 mph), so I think it's not a bad idea to use higher pressure when going long distances at 130 km/h. I mostly use my XF for long journeys in the weekend and short drives for shopping during the week. Since I can't change tyre pressure on a daily basis, I often end up driving around with the high pressure all the time. And I don't think it feels much harsher on my 19" wheels.

 

You are absolutely right. Jaguar has always done it like this. Other cars require higher pressure when heavily loaded, but Jaguars require higher tyre pressure when driving fast. It used to be, that the normal pressure was the one for driving faster than 100 mph. Afterwards they briefly mentioned, that if you didn't drive at or above 100 mph, you should reduce the tyre pressure. I never understood how to change the tyre pressure at 100 mph. Sounds dangerous to me ;-)

I often use the high pressure, even though we are not allowed to drive that fast. Even when I go to Germany once or twice a year, I don't often drive much above 100 mph. Experts often advice car drivers to use the high pressure to save petrol and be more friendly to the environment. Also if I go on a longer trip with a lot of weight in the car, I think it's better to increase the pressure, like other car manufacturers advice when driving with heavy load.