Agreed, very strange. I’m curious what accounts for the difference?

 

The key phrase is closed road use. (racetrack)

There is often a desired, optimal HOT tire pressure when running a car hard, for best handling. I know that Lotus recommends a lower cold pressure when on a track.. The hot pressure would still be the optimal.

Running the reduced pressures for street use would make the tires subject to excess flex (and maybe even bent wheels).


++++++++++++

And I noticed that everyone in this Topic says that 'normal cold pressure is 37 PSI. With these suggestions in mind, I looked at our recommended pressures on our door jam...and it say 36 PSI! Was the value increased later? Or is it because our F has 20" wheels?

 

No, 36psi was recommended for my ‘14 as well with 19” wheels.

 

Good, I'm not THAT forgetful... yet.

Perhaps the difference is SUMMER air VS WINTER air?
Disclaimer: I'm not an expert, but I DID stay in a Holiday Inn Express once!

 

Thanks for posting that! I wonder if that message was added in later years?

I have a 2014 XJR with Y speed rated Michelin Pilot Sport 4-S tires. Y speed rating is 186MPH.
When I do top speed racing I always increase tire pressure so never have seen that message. Currently running about 174 mph in the standing mile and I always keep my foot in it thru the lights to about 180 mph on the speedo which of course is not a certified measuring device.

I put all 4 tires to 41 psi and my door sticker says 34 psi is stock. As checking tire pressure is one of my checks in between runs I have seen it rise to as much as 50 psi because of speed and heat! After a couple of runs I bleed some pressure off back to about 41 psi or so. I also check the lug nut torque prior to every run.

Yes I have wanted to run Bonneville and have taken exit 4 off I-80 near Wendover, Utah exit to get on the flats. So I have driven on the flats but just a tiny bit because I wanted to take a look.
But a couple of things to consider?

1. The speeds I run require a fire suppression system and a full roll cage at Bonneville. Not what I want to do to my street car! But man a full 5+ miles flat out would be unreal!! So compared to other top speed events Bonneville is the top one and has the most regulations.

2. If you talk to anyone who has run Bonneville they will tell you that the salt is in EVERY nook and cranny of the car. So cleaning it all out is almost impossible. I can only imagine the corrosion that packing salt into the Aluminum body of an XJ would do in a couple of years?

So I compromised and started looking for other events that did not require such drastic safety regulations. And perhaps closer and less expensive to attend too.
.
.
.

 

Wendover is technically in Nevada, but everything there is close. On the Utah side of the border, there is really nothing except a gas station and a rest area with an observation tower. The Nevada side (Wendover) has several casinos and hotels and is a reasonably sized town. The Enola Gay apparently launched from the airfield there.

For the record, I wasn’t driving on the salt flats. They’re all underwater right now. I’m curious what impact driving on a relatively soft surface (salt) vs a hard surface (tarmac or concrete) would have on tire pressure requirements during high speed travel?

 

Yes that is a problem and I do see that the surface is a big deal. That was another reason I did not chance it. There have been stories of breaking thru the salt and into mud.
Thanks for the correction on the state too!
.
.
.

 

The state thing is really a distinction without a difference. It’s all one area but the hotels happen to be on the Nevada side.