I think every operating manual you'll every read always says to refer to the door panel instructions for proper tire inflation pressure (with warranty voiding warnings).

The door panel sticker chart says to inflate the tires to 30psi
The tires are rated at max 44.

The dealership says they like to run them at 38, after chastising me for having grossly under-inflated tires (28) which I didn't think was that far off the door sticker value.

I agree that 30 seems low if the tires are rated at max 44, but why does the factory emphasize the importance of following the door sticker chart (30), when the dealer recommends (with warranty voiding statements) running at 20% higher pressure (38)?

 

I go with the door stamp value then I bump up the front a half pound or so and reduce the rear about the same. Probably doesn't make a difference to do so, but my reasoning is the front carries more weight hence needs a little more pressure. Mine are wearing fairly evenly across the tread so it works for me.

As for the tire stamp of 44 lbs. Since you can put the same tire on many different vehicles with different vehicle weights it is simply what it says, the maximum pressure you should ever put in the tire. I could be wrong on all of this (no expert), but I believe the manufacturers weight is based on the weight of the car itself and so should be most accurate. I'm not at all sure why the dealer would recommend such a high pressure for normal driving.

Yeah I know, not much help.

 

For normal commuter type driving. If you underinflate the edges will wear more than the middle, if you overinflate the middle will wear more. I suggest you purchase a tire tread depth gauge, cheap little thing whree you stick a stem between the treads and it reads out in 32nds of an inch. Measure each tire across, inside, middle and outside and also at several locations around the tire. Record these numbers. In about 1000 miles, measure again. Compare these numbers and you will see in order to get even wear (not withstanding a bad alighment) if you need to add, take out or you are good on pressure. Just a suggestion if you want even tire wear.

If you track or drive fast, then this procedure does not apply.

YD

 

I run 36psi in the front, and 34psi in the rear. It works for me, and my tires wear as even across as they can with -2deg camber front and -1.6deg camber in back. I also corner fast alot.

 

That 44lbs max is for a fully loaded car and a full tank of gas, aka as heavy as possible. 38 to me is way high. 30-32 is more like it. When they warm up, if they are set at 38 cold, they will end up near 40-42 warm. Again, way too high. If they are at 30-32 cold, warm will be 34-35 which is average.

 

I run 38 psi in any Goodyear Eagle RS-A, onyl to remove that horrible tire noise. On the Dunlops that I now run, I set them to about 36 and yet to have a problem.

 

205/45 17s and mine recommends 35PSI...

 

Do what it says in the door, NOT what the manual says and not what the dealer says. Ignore the maximum rating. When storing the car, its good to set the pressure to the maximum rating and sometimes cars come shipped with the tires at maximum pressure

Most likely the door sticker is going to have the proper pressure for the weight of the car with the options you have bought. So its not uncommon if you have a stripped car, same tires, and a loaded car, there may be differences in what the plates say.

 

Our sticker says 35 psi all around, and that's what I do. I rotate front/rear about every 3,500 miles and the tires (Dunlop 9000s) still look new at 14,000 miles (mixed city/highway driving).

 

The same thing happens to me after I take my car to the dealer.. they automatically bump my tire pressure up to 40! I don't know why. I always end up putting them lower, like 34-36. BTW I'm running run-flats on 16" factory rims for my '05 MCS.

Anyone have any info as to why the dealership puts my air up to really high settings?

 

When mounting runflats, it is neccissary to use higher pressure to get the tire to seat on the rim than if they were mounting regular tires. They don't always lower the pressure back down when they are done. I suppose they assume most people wouldn't notice or check the pressure afterwards.

 

Run flats require higher psi to protect the side walls of the tire. When a run flat tire goes flat the side walls are strong/stiff enough to hold that corner of the car's weight up to allow you to drive at 50mph for 100 miles.

I got rid of my run flats years ago, I now run a 215/40/17 with 36-38psi in the front and 30-32psi in the rear. Oh, I also carry a air pump and tire sealant just in case. The last 5 flats I've had, have all been in my driveway.

In the originial posters case; depending on the type of tire, weight, ride comfort, style of driving, types/condition of roads, and weather should determine what psi he/she needs in their tires.

Start at 30psi all around. drive mix conditions 50-100 miles. Then add 2# just to the front, drive again same distance. Add 2# to the rear, drive. Keep doing this until you get to 40#. Check paragraph above, set tire psi at what you like. Then take your MINI to IT'S favorite road and have fuuuunnnnn.

 

32/33 cold on non-runflats when I track it. Generally it's best to stick with the door otherwise.

You can always take a bit of chalk and check your wear if you want to make it perfect. Also many tire shops are using nitrogen now. Nitrogen doesn't have vaporized water and is less susceptible to temperature changes. Set it and forget it.

 

I've noticed that some use a different tire pressure in the rear vs. front.

I am currently running the stock all season runflats 205/45/17 with S-lite wheels on my 06 MCS.
During the summer, I run Michelin Exalto PE-2 tires (non-runflats) size 215/45/17 on OZ Forgiata wheels. I also have the JCW suspension and an Alta 19mm rear way bar.

I prefer handling over comfort. Would the handing/grip be better with different tire pressure?

Thanks.

 

Yup, as others have said - the tire doesn't know what vehicle it is on - the maximum rating is a calculated value of the most air pressure it can safely hold, but that doesn't make it correct for the vehicle application or your driving conditions.

Start with the door figures and adjust from there.