What Pressure to Fill my Winter Tires

[SikhF80]

I just bought winter wheels for my F80
Square Setup
BBS SR-19 18x8 5x120
18 inch Yokohama Ice Guard 245/40/18

Tire Says never to inflate pas 40 psi. What tire pressure should I fill it to? Thanks

[FirstF80InSpace]

I've been running 34 PSI on all four corners with my 255 35 19 square set up. I find it's the perfect balance between handling and ride comfort. Don't go too high in PSI given all the potholes during the winter months.

[einscot]

whatever you do, don't go 1 psi too low on the front corner...

[CanAutM3]

From the owner's manual: 31psi front and 33 psi rear for 18" winter tires.

[Yas_sir]

Think I saw this on another thread, but is there a minumum psi needed on the front tires to reset the tpms? My tpms reset keeps stalling at 49%.

[SikhF80]

Originally Posted by CanAutM3

From the owner's manual: 31psi front and 33 psi rear for 18" winter tires.

thanks. My 4 wheels and tires are all 245/40/18. Will leave them at 34 psi

[rcw119]

Originally Posted by Yas_sir

Think I saw this on another thread, but is there a minumum psi needed on the front tires to reset the tpms? My tpms reset keeps stalling at 49%.

Originally Posted by Yas_sir

My tpms reset keeps stalling at 49%.

I'm having the same issue. Put my winters on and reset fails someplace between 2 and 50%.

[halfempty]

It all comes down to the load rating of OEM vs whatever new tire you have.

Check out this article from toyo regarding load index inflation tables

https://toyotires-1524598101.netdna-...s_20151020.pdf

In general, as the load index increases you need less psi in order achieve the same load capacity of the tire. However, most of the tires that we are being offered from places like tire rack have about the same load index and therefore will do fine with the same psi (they've likely thought through some of this stuff already). For instance, the OEM rear 19inch MPSS have a load index of 100. The Yokohama that you just bought has the same load index of 100. Therefore, you can pretty much use the same psi in the rear. For the front, the oem psi of 31 on a 255 MPSS with a load index of 96 works out to a total load capacity of 1382lbs (see chart on pg 29). Subsequently, a pressure of 34 on your new tire might be a bit too high for the fronts. The article states that one should never go under the oem load capacity (i.e. under inflate the tires), but suggests that going a little over is ok. I might be concerned about overinflation causing of bit of uneven wear, however. For the rears, using the OEM inflation pressures is likely best, but over by a bit is not likely to matter too much given the same load index. In the fronts, however the combination of increased load index and increased psi may change wear, and likely possibly how the tire performs.

It seems a little anal, but you wouldn't be asking the question if you didn't have a little ocd going on like most of us.

By the way, those BBS SR-19s are beautiful wheels. They're are a consideration for my next set.

[SikhF80]

Originally Posted by halfempty

It all comes down to the load rating of OEM vs whatever new tire you have.

Check out this article from toyo regarding load index inflation tables

https://toyotires-1524598101.netdna-...s_20151020.pdf

In general, as the load index increases you need less psi in order achieve the same load capacity of the tire. However, most of the tires that we are being offered from places like tire rack have about the same load index and therefore will do fine with the same psi (they've likely thought through some of this stuff already). For instance, the OEM rear 19inch MPSS have a load index of 100. The Yokohama that you just bought has the same load index of 100. Therefore, you can pretty much use the same psi in the rear. For the front, the oem psi of 31 on a 255 MPSS with a load index of 96 works out to a total load capacity of 1382lbs (see chart on pg 29). Subsequently, a pressure of 34 on your new tire might be a bit too high for the fronts. The article states that one should never go under the oem load capacity (i.e. under inflate the tires), but suggests that going a little over is ok. I might be concerned about overinflation causing of bit of uneven wear, however. For the rears, using the OEM inflation pressures is likely best, but over by a bit is not likely to matter too much given the same load index. In the fronts, however the combination of increased load index and increased psi may change wear, and likely possibly how the tire performs.

It seems a little anal, but you wouldn't be asking the question if you didn't have a little ocd going on like most of us.

By the way, those BBS SR-19s are beautiful wheels. They're are a consideration for my next set.

Thanks man! Yea my current setup is 18" + same size tires all around. I would probably leave it at 33psi

[Kief]

CanAutM3 our resident tire guru
I have an OT winter tire psi question for you regarding my X5M. I was surprised when I swapped my summers for winters last week, that BMW recommends 36/32 for their squared 285/40/20 winter setup. I found it odd to recommend higher psi front than rears, no?
Been running the 36/32 for a couple of weeks now, but haven't really driven aggressively since the rubber is new. Would you go with BMWs recommendation?

[CanAutM3]

Originally Posted by Kief

CanAutM3 our resident tire guru
I have an OT winter tire psi question for you regarding my X5M. I was surprised when I swapped my summers for winters last week, that BMW recommends 36/32 for their squared 285/40/20 winter setup. I found it odd to recommend higher psi front than rears, no?
Been running the 36/32 for a couple of weeks now, but haven't really driven aggressively since the rubber is new. Would you go with BMWs recommendation?

The reason I could see is that the staggered summer tires have taller diameter in the front relative to the rear. Inflating the front tires more on square setup will help preserve the rolling radius closer to the stock staggered setup.

And BTW, I don’t consider myself an expert in tires. I am just curious about everything and like to understand how things work.