Seeking DCSki wisdom on snow tire pressure
13 posts
11 users
4k+ views
Denis - DCSki Supporter
January 8, 2010
Member since 07/12/2004 🔗
2,201 posts
I have Cooper Arctic Claw tires, no studs, on a '07 Outback wagon. I have been unable to read anything on the sidewall about recommended pressure range and unable to google it. (They hide it on the tire or use print too tiny for my eyes and google searches result in encyclopedia covering everything except what I want to know.) Jiffy Lube here in VA puts 30 lbs. in them. Last year in UT Jiffy Lube put 44 in them and assured me it was correct. In the past 2 weeks I've experienced fishtailing as bad as 2WD cars with standard tires in VT and NH on the 30 lb inflation and I don't recall any problems in UT last season. I realize that the correct pressure involves the tire, the vehicle, the load, and the load distribution. I could make this a much longer post but that's the essence of it.

What say you?
fishnski
January 8, 2010
Member since 03/27/2005 🔗
3,530 posts
Back in the day it was thought that low pressure was better..Now they say a narrow tire with higher tire inflation gets a better grip in Snow/ice.....still better for fat & low tire pressure for driving in sand, like down here at the beach.
wvrocks
January 8, 2010
Member since 11/9/2004 🔗
262 posts
Tire pressure for your Subie should be printed on a sticker on the driver's door frame below the Nader pin. I'd start there and experiment. Pressure listed on the tire sidewall is usually the recommended highest pressure the tire should be inflated to, which isn't necessarily the best pressure for your car or conditions.

One reason you could be experiencing fishtailing or other poor handling is tire wear, the other is that the snow and road surface condtions could simply be different. Salt and slush mix compared to dry packed powder.
RLE
January 8, 2010
Member since 12/17/2009 🔗
17 posts
Other question, newer tires on the front than rear or did you rotate them? Even back in the 80s up in NH we ran narrow tire in the winter. Not a new thing, but a smart thing.
comprex
January 8, 2010
Member since 04/11/2003 🔗
1,326 posts

30 psi is a little low for that big a car,

but bear with me whilst I play Captain Obvious:

How old are the tires and is it possible you've worn down past the snow-duty portion of the tread?
Bumps
January 8, 2010
Member since 12/29/2004 🔗
538 posts
As mentioned already the tire pressure should be on the door jam. I would be careful running low pressure. It allows the tire to flatten out given more contact to road surface, but doubtful the difference is enough for the risks. I would save that for emergencies only. Risks include breaking the bead and spinning the the tire on the rim or even going flat. If the tire is not made to run flat it will destroy the side wall. This can happen pretty quick on pavement.
Denis - DCSki Supporter
January 9, 2010
Member since 07/12/2004 🔗
2,201 posts
Thanks everyone. I am going to run them at 35-36 for a while and see how that works. The conditions I experienced in VT & NH were black ice for miles with wrecks and overturned trucks on the roadsides at a rate of ~ 1-2 per mile. This is probably pretty unusual and the only effective tactics for it are to slow down a lot, or be somewhere else.
jimmy
January 11, 2010
Member since 03/5/2004 🔗
2,650 posts
Hi Denis, Let us know what you find out. I've been looking into the matter in general so none of this has been subjected to any legitimate form of peer review grin . I had to buy winter tires in a hurry last week, Firestone winterforce was all i could get that day. Read some reviews on the internets and the only bad reviews seemed to involve a heavy vehicle with tires that were underinflated.
rmcva
January 11, 2010
Member since 01/28/2004 🔗
187 posts
I posted this link on another thread but here it is in case you missed it.

Tire Rack has some good info on tire pressure.

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=73


I've often read that the rule of thumb is the psi increases or decreases 1 psi per 10 degrees change in temperature. To show that, I created the following chart as a guide. For example, if you set the tire to 30psi when the temperature was 70 degrees then driving to an area of 10 degrees the tire pressure would drop by 6 degrees - resulting in only 24psi in that tire.

http://i824.photobucket.com/albums/zz167/rmcva/Tire-Pressures.jpg

The Colonel - DCSki Supporter
January 11, 2010
Member since 03/5/2004 🔗
3,105 posts
Another interesting consideration is getting your tires filled with nitrogen vs. air. I have this on my Toyota :)Highlander and the result is supposed to be uniform pressure regardless of temperatures, allows a little better wear also.
The Colonel
Jim
January 11, 2010
Member since 11/22/1999 🔗
317 posts
Follow the VEHICLE manufacturer's recommendation (period). Tire sidewall pressure is the maximum for the TIRE - not the vehicle/tire combination. For that, the vehicle manufacturer knows best. Any tire manufacturer will tell you that. Find the tire pressure placard - on either the door jamb sticker or on the glove compartment. Definitely in the vehicle owner's manual.

On Subaru's and any full-time AWD vehicle, tires must be changed out four at a time. Minor differences in radius due to wear from new versus used tires will destroy differentials.
Denis - DCSki Supporter
January 14, 2010
Member since 07/12/2004 🔗
2,201 posts
Originally Posted By: The Colonel
Another interesting consideration is getting your tires filled with nitrogen vs. air. I have this on my Toyota :)Highlander and the result is supposed to be uniform pressure regardless of temperatures, allows a little better wear also.
The Colonel


Nope. Doesn't work that way. The Ideal Gas Law applies to all gases. Nitrogen will not cause oxidation of the rubber.
http://en.wikipedia.org/wiki/Ideal_gas_law
David
January 14, 2010
Member since 06/28/2004 🔗
2,444 posts
PV=nRT !!!!!
DCSki Sponsor: DCSki

Ski and Tell

Snowcat got your tongue?

Join the conversation by logging in.

Don't have an account? Create one here.

0.14 seconds