Author Topic: Winter tires: How do you decide what pressure? (Read 3781 times)

Noobee · « **on:** December 29, 2008, 06:53:27 pm »

I was just reading the owner's manual and it says that you should inflate your winter tires at least 4.3 psi greater than what's on the door jam. I was also reading an article saying you should increase your regular tire pressure at least 4 psi. And this is interesting. The US based BMW Advanced Driving Course recommends BMW owners inflate to maximum recommended pressures for everyday driving. Manufacturers pressures are minimum pressures for low speed round town driving and obviously still not enough.

tpl · « **Reply #1 on:** December 29, 2008, 07:05:39 pm »

It always was a given that pressures should be increased for continuous high speeds. Also that winter tires required higher pressures. These were not urban myths; in both cases it was to help the tire run cooler. Those old winter tires were very (thermally) inefficient with their thick heavy treads.

I wonder if the modern lack of such info is driven by lawyers, Both my cars say nothing about different pressures. My BMW did say it wanted another 3 psi at the rear when carrying a full load.
The BMW driving school I went to made no comment about tire pressures.

rrocket · « **Reply #2 on:** December 29, 2008, 07:12:34 pm »

I asked the Tirerack what PSI my new Xi2 should be inflated to. They told me the recommended OEM pressure of 33 PSI. I wasn't sure if they were right...so I contacted Michelin. They gave me the same answer...

tpl · « **Reply #3 on:** December 29, 2008, 07:39:56 pm »

A point here. If you get a fresh new set of tires installed they will, we hope, be set to the correct pressure at the air temp of the fitting shop.

In winter, if you park outside, the next morning they could be 6-7 psi too low and require an immediate pressure adjustment.

A perfect tire shop would of course pump them up a bit too high if fitting them on a cold day.

Noobee · « **Reply #4 on:** December 29, 2008, 07:58:08 pm »

What about the urban legend of lowering your tire pressure in winter to gain more traction?

rrocket · « **Reply #5 on:** December 29, 2008, 08:08:22 pm »

No really an urban legend. That's to be done when you are STUCK. It allows more surface area to crawl out of being stuck. Not recommended for driving though. Off roaders use this technique when they get stuck in much or sand....(or snow)

Noobee · « **Reply #6 on:** December 29, 2008, 08:16:24 pm »

I tried that with a van....I got myself in a bigger hole because I was sinking even deeper and became even more stuck. If I had a tall 4x4, this approach may have worked.

I think in most cases when you're stuck you're also pinned too like my friend was this weekend in his Civic.

rrocket · « **Reply #7 on:** December 29, 2008, 08:23:46 pm »

^^^^Yea. Often if you get snow up under the undercarriage you are pretty much screwed....

I've here the traction mats or racks that stow in the trunk work really well....but I've never used one.

airbalancer · « **Reply #8 on:** December 29, 2008, 08:31:45 pm »

saw those at Zellers last week, but I have not been stuck since I got the 4 X4,
They only look about a foot long, would that be long enough to get you out

rrocket · « **Reply #9 on:** December 29, 2008, 08:37:48 pm »

^^^^ The Go Tread mats are 40" long. I would prefer the Go Treads...

Computron · « **Reply #10 on:** January 02, 2009, 01:01:31 am »

Those are useless... you get unstuck only to stop the car, and pick them up? That totally defeats the purpose of those things!

You're better off buying the "AutoSock"

a u t o s o c k . us

Or if you're thinking the high-tech fabric is a little too wimpy, get "SnoBootz"

s n o b o o t z . com

Sorry I'm a new user, and the dumb forum doesn't allow me to post URLs or images -- google it yourself.

Still, I'd prefer a set of 4 dedicated winter tires - yes even for Vancouver. Winter tires FTW!

airbalancer · « **Reply #11 on:** January 02, 2009, 08:47:49 am »

Sorry I'm a new user, and the dumb forum doesn't allow me to post URLs or images

oops, I said I was going to be more +ve
The reason for the 10 post min is to prevent spam

safristi · « **Reply #12 on:** January 02, 2009, 09:22:52 am »

does

help to get ya MOVING?..................................i just put my car mats under the driving wheels.........worked well over the years................a small shovel and a bag of grit is good too....................(and ya can eat tha biscuits too...Southern j/k)

Noobee · « **Reply #13 on:** January 02, 2009, 09:07:59 pm »

According to retailers taht sell the autosock, they're pretty much a one time only thing to get you out of a jam.

Computron · « **Reply #14 on:** January 03, 2009, 02:18:23 pm »

Quote from: Noobee on January 02, 2009, 09:07:59 pm

According to retailers taht sell the autosock, they're pretty much a one time only thing to get you out of a jam.

It's to get you out of unplowed streets to where it's has been cleared. It is an emergency use device afterall, I wouldn't be trying to use it the whole winter, if you get that much snow that's what winter tires are for.

They should be ok on snow/ice covered roads w/o aggressive tire spinning... so as soon as you get out of the side streets and if the main streets are clear - head to the gas station and take them off to ensure longevity.

However, I did read a silly review where some dude shredded them (by mounting on winter tires

)... I don't think it was meant to be used on those aggressive treads that way. He already has winter tires, not sure what he was thinking LOL

Noobee · « **Reply #15 on:** January 03, 2009, 07:55:36 pm »

Quote from: Computron on January 03, 2009, 02:18:23 pm

However, I did read a silly review where some dude shredded them (by mounting on winter tires )... I don't think it was meant to be used on those aggressive treads that way. He already has winter tires, not sure what he was thinking LOL

I wonder what tires he had. The Michelin X-Ice i2 has no aggressive tread at all but it's considered a winter tire because of it's performance on ice.

Dave L · « **Reply #16 on:** January 05, 2009, 11:02:00 pm »

Used it for years. Used to keep some in a small paper lunch bag in the trunk. Spread it on top of the tire tread, immediately at the base of the tire so that it gets drawn in under the tire.

Works well.

No experience with used kitty litter. Just the new store bought kind.

DaveL

dr_spock · « **Reply #17 on:** January 05, 2009, 11:31:21 pm »

Quote from: Dave L on January 05, 2009, 11:02:00 pm

Used it for years. Used to keep some in a small paper lunch bag in the trunk. Spread it on top of the tire tread, immediately at the base of the tire so that it gets drawn in under the tire.

Works well.

No experience with used kitty litter. Just the new store bought kind.

DaveL

I used to carry a bag around in my old hazmat job. Works good in proving traction in a pinch in addition to soaking up PCB spills. I don't think it is a good idea to driving around with used kitty litter. There may be health issues if you're pregnant.

safristi · « **Reply #18 on:** January 06, 2009, 10:41:51 am »

..Ta fer the straight POOP...........woz KITTY_SH*T involved............Consumers REPORTS wants ta KNOW...............

Iso Octane · « **Reply #19 on:** January 08, 2009, 07:51:57 pm »

Regarding lower pressures, I tried it and I believe it works.

I've been really struggling with traction this winter, mainly when getting going from a stop. Today I decided to drop the tire pressure a bit to see if that would help things. The door jamb says 28 psi, and I had been running 32 psi. Dropped that down to 30, and it got noticeably better. Wheel spin is inevitable going up slopes or deeper snow, and there was a lot less of it after the pressure drop.

YMMV