The plate on the console says that I should have 245/50/ZR17 tires with 26# in the front and 28# rear. I have 225/55/R17 and the local shop insists they should be 32# front and 34# rear. Which is correct?

 

Follow the manufactures (Jaguar) recommendation. It will soon be very clear by the tire wear if not correct.


my manual shows two sets of recommendations, one set for normal (all speeds & over 100 mph) driving and one for “comfort” (under 100 mph) .

I followed the Jag “normal” recommendation on my 18” tires (same of the 17” wheel spec) until the tires showed increased wear in the center of tread vs the edges. A dead giveaway for overinflation . Lowering the tire pressure slightly closer (mid-point to the under 100 mph recommendation) gave me even wear.




I’ve used the mid-point between the 2 sets of Jaguar’s recommendations for several different brands of tires with the same good results.

 

Wrong tyres anyway ..narrower tyres more pressure. Increase pressures in proportion to the tyre width 245 divided by 225 approx 10%

Front (comfort) 28.5 psi
Rear ( comfort) 31 psi
What your garage suggests is fine as its lower than the high speed pressures with 10% added

 

The first year of tire pressure experimenting (2012) with my wife's 2006 XK8 proved the optimum treadwear pressures to be 32 psi front and 29 psi rear. Her car has 19-inch wheels with 245/40/19 front tires and 255/40/19 rear tires....

 

I was told by an auto enthusiast/racer years ago that the front tires should always be pressurized 2psi higher than the rears as the engine weight is on the front, and the rears are 'lighter weighted'. I have followed this suggestion for years and found the tire wear/ride to be an improvement over the higher front suggestion.

 

for what it’s worth, For the 17” / 18” / and 19” tires, Jaguar does NOT suggest a higher front wheel pressure.

For the X-100: Fully fueled with no passengers or cargo F/R weight distribution is about 51/49 for a convertible and 52/48 for a coupe.

not significantly front heavy compared to most vehicles.

My successful “Midpoint” tire pressure is :

Front 29 psi Rear 31 psi

check cold of course.

Z

 

What people do with the correct tyres is irrelevant as this guy has the wrong narrower tyres ,225 not 245/255 which need more pressure than the wider ones. see post 3. Would not be legal in UK .you would not get your roadworthy.
Sure its fine in Canada ...Cuts down thro the snow better.

 

My opinion; the OP would enjoy his car more if the tires were replaced with the stock sizes.

BTW, My ‘02 with stock sized 18” tires does surprisingly well in the snow packed roads during our short winters. My longest trip in the snow / ice was 450 miles the night I purchased the car. and had to drive it back to Oklahoma from Iowa.

Z

 

When you consider that two new 255/45/18 tyres in the UK are the same price as one tank of petrol maybe the right tyres dont sound too expensive.

 

Only had my XK8 for a week now. I am pretty sure it sat in previous owner's garage for a long period. The tires or Michelin radials and were purchased new January 2020. The ride is bumpy, and I suspect the tires now have flat spots. I have read that this goes away after a while with driving. I am a bit worried that the car sat for close to a year. Will they work out in time?

 

drive the car for a continuous 1-2 hours at different speeds, mainly highway speeds.

If tire flat-spotting hasn’t smoothed out by then, it never will.

Z

 

Find the flat spot with your hand and rotate it to the top . Blow them up to 45 psi and leave it a couple of days then reduce to say 32 and give it a drive.If not OK change the tyres and sell the old ones.

 

Back in the seventies I remember a tire shop placing a tire on a rotating machine and "shaving" off tread to help round out a tire. Does anyone know if that is still done?

 

my 2019 Jaguar XE T25 AWD.
My tire pressures are set at 43 psi for the fronts
and 47 psi for the rears . This creates a “hard ride”. I have tried lowering to 34/36 psi but thus setting triggers TPMS light ( low air warning)
why such high tire pressures ?
tires are Continental Pro Contact 225 45 18 (95)
thanks in advance
Richb55

 

More narrow tires require more pressure. That said, the pressure you need to avoid the warning does seem high.

I'm not familiar with your model

Z

 

I worked at a Shell gas station in the 60's near Macon, Ga. We had a machine for 'Truing' tires. Amazing how much rubber came off in odd spots to round a tire.

 

I grew up in Eatonton. Macon was a big trip for us. I saw the same thing in an independent tire store as a teenager. I wonder if they still do this and especially new radial tires.

 

"Rock Eagle"

 

"Brer Rabbitt"

 

P.M. sent.