Seeking DCSki wisdom on snow tire pressure
January 14, 2010
13 posts
11 users
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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?
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.
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.
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.
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?
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.
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.
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
. 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.
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
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.
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