Curious as to what everybody is running psi-wise. I have the 20'' tornado wheels with 295 back and 255 front. Internal vehicle settings say to run 37 all around but when it was delivered all wheels were at 33. Wondering if they know something I don't or if they actually just need some air. Typically I would just follow the manual, etc but seems there are many knowledgeable folks on here so any help would be appreciated.

 

You are running the stock P-Zero tires (on your R, I'm assuming)? Look at the door jam, there should be a label. Pretty sure it's 36 PSI all around. That said, some of us like to run it at lower. I run my around 33-34 PSI. Only annoying thing is the monitor might complain you have low tire pressure.

 

Most dealers are sloppy about checking tire pressures. More often than not, they come over-inflated off the boat. However, there's nothing wrong with running them at 33 psi. They might be a little grippier.

The recommended setting is usually more about best tire wear.

 

I was thinking that as well. Thanks.

 

Yes P-Zeros, it's an S and I did look at the door jam pressures too and its definitely 37 but I think I'm going to leave it a little lower for added grip and a slightly softer ride. TPS only acts up when when I get on the throttle hard so I can deal with that. Haha.

 

Interesting, do you have the AWD by any chance?

 

Yep, its the AWD.

 

You are absolutely right. When I picked up my XJ, the tires were at 50 psi all round...

 

I run 36 psi all around on my 2015 R and it does well on spirited drives. The car has been the dealer twice (1st for post break-in oil change and 2nd to fix the AC and gas fill issue). Both times the tech filled the tires to between 40 - 41 psi. Definitely feel the difference and have had to back it down to 36 psi. Not sure why they don't follow the factory spec.

 

Is there a TSB on this I don't know about...? Do tell...

 

In on road situations as opposed to off-road 4 x 4s lower pressures do not necessary lead to extra grip and in fact may reduce grip as the tyre can hollow in the middle under braking and leave you just the shoulders on the road. Many advocate for safety slightly higher rather than slightly lower although if you go too far you get the opposite problem with grip only in the centre ofthe tyre and none on the shoulders.

 

Interesting. Guessing maybe the added weight bumped the factory pressure up.

 

The dealer installer a new filter in the filler neck (as far as I can tell). I can now fill without the 'click dance'. The appt was to install the new AC compressor and direct pressure sensing electronic control valve to fix the AC issue. They did the gas filler neck filter at that time. I thought something looked different in the filler neck when I filled it up and was pleasantly surprised that I got to a full tank from 1/4 tank without the gas pump shutting off a bunch of times during filling. Nothing was noted about it in my invoice, though.


(back to your normally scheduled thread)

 

Thanks for that,my first scheduled service is in October and I will inquire then...

 

I run the same at 36psi. However, I have the opposite experience with the dealer ... every time that i have gotten the car back from them, they have lowered it to 33-34 PSI and i get a low tire warning.

 

I'm running at 36 psi also, recently the TPMS informed me the pressures on all four tires were low. When checked with a pressure gauge it measured 25 psi. I didn't think the system would allow them to go that low. I'm going to try one more time to see if they'll go off and read 25 psi. Tires are almost end of life anyhow after 15K miles. The M3 I had would always warn me within 5 psi of set pressure.

 

25psi, that sounds odd. unless you overrode the settings somehow. i definitely get warned when it's around low 30s.

 

Agreed, I be suspecting a defective tire gauge and would check with a different one.

 

I keep mine at 35 but when I got the car they were all at about 32. I've always gotten decent life out tires simply because I stay on top of the tire pressures and regularly check them.