Tyre pressure for wider tires.

[X5chemist]

Is anyone running 255/60R17s from 235? How much tire pressure are y'all running front and rear? Though BMW recommends no tire rotations, I'm doing it after a full suspension refresh. So far, 1000+ miles and no issues.
Three to four PSI were added above stock. As I drove away the pressure light came on. I was already dreading heading back to have sensors checked. Once home, I realized I had to reset the monitors. Pushed button for a few seconds then drove down the block The monitor light turned off.

[nick325xit 5spd]

nominally, required pressure can be lower to achieve the same load rating. (note that you probably have a higher maximum load than the standard tire.)

but really, i just set pressures by feel. it takes some experimenting to get it where you like it. I generally like higher pressures for long highway trips than stooging around town.

[X5chemist]

Yup, most of vehicles get wider tires after stock ones are toast. The wider tires have ~3500 miles on them. Directional 255/60R17 Nexen Roadian HP SUV run great. It needs a non directional 255/60R17 for a spare. I'll monitor wear to find an ideal pressure. So far, they feel great for city driving.

[nick325xit 5spd]

Originally Posted by X5chemist

Yup, most of vehicles get wider tires after stock ones are toast. The wider tires have ~3500 miles on them. Directional 255/60R17 Nexen Roadian HP SUV run great. It needs a non directional 255/60R17 for a spare. I'll monitor wear to find an ideal pressure. So far, they feel great for city driving.

no real reason not to leave the spare 235. 255 spares don't fit that well in the tire well. (he says with a 255/55-18 spare.)

[X5chemist]

Thanks nick325xsit 5spd. I thought a 255/60 would fit okay. I'll just replace the unused OEM 235 spare.

[FordNLNR]

What PSI does BMW recommend for 235/65R17 tires?

I have the opposite situation: I dumped my 255/55R18s for stock 17s in order to get a better ride and all-terrain tire options.

[X5chemist]

32 PSI front
33 PSI rear
I’ll drive it another week before taking 1-2 PSI out. The ride seems a little hard.

[workingonit]

Originally Posted by FordNLNR

What PSI does BMW recommend for 235/65R17 tires?...

I always have my trunk loaded with spare parts, general maintenance parts (fuses, wire, tie-wraps, oil, coolant, etc.), and my growing supply of metric & BMW-specific tools (I mainly worked with SAE tools, on old trucks, cars, & my '66 Chevelle).

Since I haven't weighed the tools, etc., I assume that I should run my tire pressure at 39 psi in the rear, and 32 psi in front, in my 235/65-R17 tires (on stock Type 57 wheels), as dictated by the owner's manual.

90% of my trips are to fetch groceries or other supplies (loaded in the trunk and/or rear seat), so I probably wouldn't consider the 39 psi too high, on a daily basis.

Besides, I've always preferred hard tire to soft, on pavement and at highway speeds. My tires have imperceptible tread wear, so far, but I'm keeping an eye out for signs that I should readjust the pressures (the front & rear suspensions/bushings are almost brand-new).

[X5chemist]

Interesting. The door tag has 32/33 on mine. Mine has about 35 lbs of "stuff". Mostly small spare parts. A quart of oil and tool kit.

[workingonit]

Originally Posted by X5chemist

Interesting. The door tag has 32/33 on mine. Mine has about 35 lbs of "stuff". Mostly small spare parts. A quart of oil and tool kit.

My door sticker shows 32/32 for unloaded, and 32/39 for loaded, for all sizes of tires (except for 61 psi, if on the T155/90 -D18 compact spare; my spare is a 17", so it's inflated to 39+).


I suppose different model year X5's have different stickers, if using different option packages. Mine is a pre-facelift E53, without air suspension, on the base wheels. YMMV