Tire pressure - weird specs?

[double_j]

I have a 2015 X5 50 with the 19" wheels on the xLine package.

I've been fiddling with my tire pressures recently (big drop in temps in the NE US over the past few weeks) and just noticed that the door sill recommends the rear tires at 46 psi cold. That said, the tires themselves have a max pressure spec of 50 psi.

I know the manufacturer pressure specs are by no means mandatory, but isn't this a little odd? There's not much leeway between the cold pressure recommendation and the max pressure spec on the tires? In fact, I'm guessing that the tire pressures could easily exceed the max spec once warm if inflated to the manufacturer recommendations.

Am I missing something? Is the max pressure spec on the tire based on a cold measurement or something?

[Rotzy]

Wow, that seems high. My 20" staggered setup calls for 36/41 and I thought that was high. I've been running the suggested pressure, but when I took my summer wheels off this winter, I noticed that the rears are worn more in the center than on the edges, indicating overinflation. I'm going to back the rear pressure off a bit this summer and see how it goes. Your experience may differ.

[Flying Ace]

Originally Posted by Rotzy

Wow, that seems high. My 20" staggered setup calls for 36/41 and I thought that was high. I've been running the suggested pressure, but when I took my summer wheels off this winter, I noticed that the rears are worn more in the center than on the edges, indicating overinflation. I'm going to back the rear pressure off a bit this summer and see how it goes. Your experience may differ.

that sounds about right. BTW, I highly recommend you read your manual on recommend tire pressures. On the X5, there are multiple pressures depending on speed and number of people you're carrying and 3rd row.

I never use the door guide, and always refer to the manual. Currently on my 20's I run 37/44 b/c I am carrying 3 adults, kids and cargo for a roadtrip. I can go up to 41/48 in my situation.

Also aside from handling impacts of overinflation/underinflation, it can also prematurely wear your tires too. I learned it the hard way on my M3's $1300 PS2 tires...

[alphaod]

Tire pressures are suppose to be adjusted based on load, how fast you plan on driving etc.

For my situation, I don't follow the 35/41. I use 39/45 cold pressures since I'm mostly driving by myself or with one passenger only, and I do tend to drive fast 80 mph at least, if not more at 90-100 often.

[Almaretto]

Those cold readings are for a filled cabin.