I have a XKR 175 which has 20" Kasuga rims an now Michelin Super Sports and was just curious what everyone's sweet spot was for tire pressure. I am thinking between 34-35 psi seems to be right but was curious what others are running.

 

Whatever it says on the door is what I use in any car. For me right now, it's difficult as we are getting 30-40 F temp swings in a day. I fill them at 25 degrees and they over inflated when it's 60... Mechanic lower the pressure to correct it at 60 and next morning they were all like 8 lbs under...

 

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I have standard 19" Carelias and running factory recommended pressures.

 

Where I live on Vancouver Island Canada, it hasn't been to cold this year, I recently had new rims installed and went with nitrogen filled, haven't had a pressure difference since then, and I fill my tires to 33 front 36 rear. For 6$ a year per tire, the local tire shop I use maintains the nitrogen all year if the pressure drops.

 

Please, please- never ever pay even a penny for nitrogen fill. It's the biggest scam going.

Nitrogen expands and contracts at the same rate as air. Think about this- If it were true that nitrogen expanded at a lower rate than air, this would result in underinflated tires at highway speeds.

The difference in molecular size is so minute that it cannot be responsible for any affect in leakage rates. If the sales gimmick theory was true and air was used for inflation, only the oxygen in the tire would leak out leaving pure nitrogen behind. This means the tire would stop loosing pressure by itself. For free.

Ask any nitrogen dealer how they get 100% of the air out of the tire when it's first mounted to ensure that there's only pure nitrogen. Actually- don't bother. They don't and they can't.

 

You will have your car at Jaguars on the Island (July 17-19) in Victoria, yes? It is the largest Jaguar show in North America and modern Jaguar sports cars (xk8, XK and XKR and F-Type are the featured models this year.

 

Standard would be 36 F&R on a Speed Pack car, which includes the 175 - but check the sticker on the edge of the door, just to be sure. A normal 5.0 XKR is 33F, 36R. I suspect the higher front pressure for Speed Pack is related to the 174 MPH top speed. Since you won't be near any autobahns, perhaps use the 33F/36R unless you're doing a track day.

 

The is a recall on the tire pressure sticker for my 2013 XKR w/dynamic pack. I picked up the sticker and put it on without even looking at what I replaced.

 

I'll be there, I was there last year, didn't enter my car though.

 

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