Winter Tires - CAUTION: DON'T MAKE THIS MISTAKE

[dmann]

I am interested in the tire pressure comments. I have the winter tire package that BWM installed when I bought the car last January. I'm pretty sure that the pressure was lower than the recommended 33 psi front and 41 psi rear. I swapped the wheels (summer to winter) myself this fall and the pressures were below recommended. In fact, I always believed that winter tires operated better with lower pressure. Presently, I'm operating mine with about 3 psi less than than the recommended pressures. Any feedback would be welcome!

 

[user 3172]

To my knowledge, the only reason drivers used to recommend running with lower pressures in winter was to create a larger contact patch particularly whilst running on snow or ice. The trade off is extra heat and wear from distortion of the sidewalls and I wouldn't recommend it for anything other that a short period born of necessity. It's only an emergency measure for poor traction and if you have proper winter tyres, they'll cope just fine as they are anyway.

 

[wilcovh]

I had always learned that the winter tyre pressure is 0.2 bar above the summer tyre pressure. A quick google on winter tyre pressure shows both michelin and nokin websites advising this.

 

[user 3172]

I had always learned that the winter tyre pressure is 0.2 bar above the summer tyre pressure. A quick google on winter tyre pressure shows both michelin and nokin websites advising this.

To clarify, I wasn't suggesting that winter tyres should necessarily be inflated to the pressures quoted for summer tyres. Clearly if a different pressure is quoted by the tyre / car manufacturer then that is the recommended tyre pressure to be used. The point I was making was that arbitrarily changing the quoted tyre pressures just because they are winter tyres or because it was colder in winter was not a course of action to be followed by default.

 

[jadnashuanh]

A plausible reason to maybe overinflate your winter tires is to account for the likelihood that you installed them when it was a bit warmer than what may be their normal operating conditions! Tire pressure will drop about a pound for 10-degrees F, easily something you might see between night and daytime conditions, or as the winter season progresses, and over the course of a few days as the fronts move in and out. This is not the same as the pressure dropping over time, which would require monitoring and an occasional top up.

 

[kaozhq]

Hey @rsplodge

Can someone please explain the comment by rsplodge on page one about the tires being "directional"? I am not sure what this means.

I just bought 4 of the BRIDGESTONE BLIZZAK LM-500 155/70-19 online from simpletire dot com and presume BMW shop will just mount them on all four rims (yes back ar 5.5") but not sure about the directional comment?

 

[theothertom]

Hey @rsplodge

Can someone please explain the comment by rsplodge on page one about the tires being "directional"? I am not sure what this means.

I just bought 4 of the BRIDGESTONE BLIZZAK LM-500 155/70-19 online from simpletire dot com and presume BMW shop will just mount them on all four rims (yes back ar 5.5") but not sure about the directional comment?

I didn't see the comment about directional. What post number is it ?

Directional tires means that the tread is designed to rotate in one direction, which squeezes water from the inside of the tread to the outside. If you flip the tire around when mounting, the tread will rotate "backwards" and water buildup, i.e., hydroplaning, can be a problem. Tires that are directional generally have an arrow that shows which direction they should rotate.

 

[Milam]

Would regular tire people know how to properly mount these tires?

I am guessing, that they are not that rare.

Please let us know how it goes.

I may do the same with our i3.
I had not planned to drive it in the ice and snow.
Maybe, I should reconsider that position.

Thanks,

/s/ Tom Milam

 

[ecoangel]

155/70 r19 v 175/55r20 just 0.1% in it

v 175/60R19: 1% so at worst around 0.6 mph at 60 mph

Well within tolerances for ABS, TPS and Traction Ctrl.

See Tacoma Tire Calculator

 

[jadnashuanh]

FWIW, when I received the BMW OEM set of winter tire/wheels...all four were mounted for the left side! The dealer remounted two of them so that I had a 'proper' set. It should be fairly obvious when you try to mount the wheels on the car which side they are designed to fit on by the directional arrows molded into the sidewalls. There are lots of tires that are directional, but the majority are probably unidirectional. Higher performance tires tend to be directional, though.