for some reason or another, i had been driving at around 34-35 PSI cold on my tires for my gs f-sport..so around 31-32 cold.

i inflated them to 1 psi below recommended psi last night, so around 34 cold in the front, 35 cold in the rear which warm up to 37/38, and the ride was considerably harsher over bumps.

what are the drawbacks/if any, of running tires about -3 psi lower than the recommended PSI that's on the door jamb?

 

I go with 32 in front and 33 rear.

 

If I recall, the tires will wear out faster on the edges than the middle when running at lower PSI but will 3 lbs make a difference in wear? I doubt it but.. maybe.

 

with lower pressure, you suffer on mpg, edges wear out a bit faster than middle

 

I've been running 31 cold all around on mine (sticker says 33) and like the ride, no adverse wear yet.

 

AWD sticker PSI is a bit lower than the F-sport.

i might just run it about -2 PSI lower all around and monitor the wear.

 

Should be fine...

 

I do that too for my fsport and it rides perfect-. No adverse or uneven wear after 10 k miles on the Michelin primacy mxm4s at 32 psi cold.

 

It's also better to run them low in the winter as well. Hard tires will slip and slide much easier.

 

I realize that the door jam specifies 35 front and 36 back. I happened to look at Tire Rack and it states

"Front: XL/RF tires required. Customer must maintain higher tire pressure levels of 42psi for proper load. *********PLEASE COPY THIS NOTE ONTO INVOICE************"

This is for the Dunlop SP Sports Maxx. Just wondering, why such disparity on proper tire pressure?

 

Its a generic statement for across the market. Its not pertaining to a specific car is it? No it isnt. So you be the judge and inflate it always to normal load pressure as on the car and then adjust base on how many ppl or luggage will be in the car. It also varies with the load rating of the tire. If the car comes with 96V and you go to 94V then you need to adjust the pressure a bit up and vice versa. Also depends on the size tires and rims.

 

You have a multiple level decision matrix for this?

Looks like I'll just stick with what the car specifies.

 

To be simple,

Adjust pressure to your own preference and not the car. You can go 3-4 psi above rec or 3 psi below rec for cold pressure. Dont follow what car always specifiy as its for the standard tires that come with it and is for maximizing handling and fuel efficiency in trade off for ride comfort for most people.

 

I generally lower the tire pressure about 3PSI in the colder months. This aids a bit with traction. Summer months, I run what is recommended.

 

It's interesting you posted this. I had 15K service done and before going to pick up the car, I noticed on the report, they set all tires to 36psi. At 5K and 10K, they set to 32. I called them to confirm if it was meant to be at this psi. The advisor said the dealership did this intentionally to give the tires more life. Me thinking well, I can always deflate a bit to my preference. Got the car and drove off the service center to find out they pumped all the way to 40psi. It was raining so hard that I didn't even want to go back. Deflated it a little bit to about 36 to see if there's a difference in ride quality. I can't really tell compared to 32s or 30s. When it was in 40s, yes, very bumpy but not much when set at a few psi more/less. I have 18" though.