Air down tires for snow and ice - JeepForum.com
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post #1 of 46 Old 02-15-2014, 09:11 PM Thread Starter
Charley3
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Air down tires for snow and ice

I have found the below to work well with tire sizes 225, 235, 30, 245, 31, and 33 x 10.5 R15.

For anyone who doesn't already know, reducing tire pressure 5 psi for snow and ice helps traction, and still enough psi to drive full speed on highway if road snow/ice melts. So if you normally use 27 psi, use 22 psi for snow/ice.

Airing down 8 to 10 psi helps traction even more, but then not enough psi to drive full speed on highway when snow/ice melts. So if you normally use 27 psi, use 18 or 19 psi.

Other tire sizes would also benefit from airing down for snow/ice, but I'm not sure how much airing down for other sizes.

I should have posted that 2 to 4 weeks ago.


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post #2 of 46 Old 02-16-2014, 07:10 AM
mschi772
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Honestly, I say it depends. I've never ever had success in WI winter conditions with reduced air pressure. I can see how airing-down would increase footprint for driving on top of very deep snow, but around here, the snow never gets so deep as to require float. Reduced air pressures have just given me uncomfortable handling, reduced ability to cut through the snow (due to increased float) resulting in increased slippage, increased tread wear on the outer tread, and as always, driving on under-inflated tires is the number one cause of tire failure. Ice is just ice, and even winter tires are only marginally better on it. Studs aren't legal in WI, but they'd be the only way to actually hope of having safer traction on ice.

Many people will actually say to over-inflate tires to reduce contact area for a better cut through the snow. Maybe, but at the cost of traction, ride quality, and increased wear on the center tread. My experiences don't agree with them any more than the under-inflation crowd.

My point-of-view/opinion on the matter is to continue to use the correct pressure. If winter conditions are so bad that you feel the need to mess with tire pressure in order to feel like you've done something productive, I highly recommend you take that as a sign to spend your energy getting some proper winter tires mounted to some cheap wheels--MUCH more effective.


There's not much harm in trying these methods, so go ahead if you really want to. If you do achieve an improvement beyond placebo effect and are satisfied with it, OK. The above has simply been my experience here in WI with numerous tires and vehicles. Your mileage may vary (ba-dum tsh!)

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post #3 of 46 Old 02-16-2014, 08:49 AM
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Airing down is no help in snow and ice, and 5psi will easily lead to a de-beaded tire since the snow piles up in front of the sidewall when the wheels are turned and the car is moving forward. It only takes about 300 pounds of force on a sidewall at 5psi to de-bead the tire.

I would think that veteran posters here would know that having more rubber on the ground results in less traction on the snow. Hasn't anyone every driven a Corvette in the snow? One lap around the block in a car with super wide tires will teach even the dumbest of you that narrow is better in snow. Airing down mostly widens the contact patch.

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post #4 of 46 Old 02-16-2014, 10:43 AM
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Quote:
Originally Posted by wilson1010 View Post
... Hasn't anyone every driven a Corvette in the snow? One lap around the block in a car with super wide tires will teach even the dumbest of you that narrow is better in snow. Airing down mostly widens the contact patch.
A better analogy would help make your point stronger.

Who drives a Vette in snow? The type of people we point and laugh at.

What types of tires are used on Vettes?
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post #5 of 46 Old 02-16-2014, 03:31 PM Thread Starter
Charley3
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We have wet slick snow/ice here. Most knowledgable people here air down.

That includes 4 wheelers, police cars and SUVs, etc.

It helps people here.

I think more tread on the ground helps, at least in our conditions here. This is with narrow tires in my climate.

It might be different with other climates or wider tires.

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post #6 of 46 Old 02-16-2014, 03:39 PM Thread Starter
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I said air down 5 psi. I didn't say air down to 5 psi.

That means 5 psi less than normal. I never said to run 5 psi.

For example, I normally use 27 psi front, 24.5 psi rear. That's in normal conditions.

For snow/ice I'd reduce 5 psi, which means I'd have 22 psi front, 19.5 psi rear.

The tire isn't going to come off bead.

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post #7 of 46 Old 02-16-2014, 04:50 PM
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Quote:
Originally Posted by Charley3 View Post
I said air down 5 psi. I didn't say air down to 5 psi.

That means 5 psi less than normal. I never said to run 5 psi.

For example, I normally use 27 psi front, 24.5 psi rear. That's in normal conditions.

For snow/ice I'd reduce 5 psi, which means I'd have 22 psi front, 19.5 psi rear.

The tire isn't going to come off bead.
Thank you for your correction.

Still, airing down is counterproductive. All wide tire cars do poorly in the snow. Whether it is a Camaro, a Corvette, or a Suburu WRX. A larger.wider contact patch is a problem, not a solution.

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post #8 of 46 Old 02-16-2014, 04:59 PM
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Quote:
Originally Posted by wilson1010 View Post
Thank you for your correction.

Still, airing down is counterproductive. All wide tire cars do poorly in the snow. Whether it is a Camaro, a Corvette, or a Suburu WRX. A larger.wider contact patch is a problem, not a solution.
Not always. I've been off-roading in snow on 31x11.50 tires and was staying on top and making good time. My buddy had his skinny 235 tires and couldn't keep up because he kept sinking.
I'd say it depends on the snow.

Just my opinion, yours will differ.
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post #9 of 46 Old 02-16-2014, 05:24 PM Thread Starter
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I've experienced signifigantly more snow/ice traction with air reduced to 5 psi less than normal.

Local cops do the same. I was talking to a Sheriff deputy who was driving a Ford Expedition with All Season tires. It was very icy that day. He was able to drive up icy steep windy mountain roads with AS tires. He told me he'd aired down a little for it.

I know lots of 4 wheel drive and car owners in my area who do the same.

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post #10 of 46 Old 02-16-2014, 05:45 PM Thread Starter
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This is interesting. I was surprised people in this thread disagree on this.

So I went to other forums for their opinions. Some say airing down helps Winter traction. Some say it makes it worse. Some say airing down a little helps traction, but airing down a lot hurts traction.

http://www.expeditionportal.com/foru...nd-airing-down

http://mforum.ih8mud.com/80-series-t...e-driving.html

Hmm. Well I've always been airing down a little (airing down 5 psi - from 27 to 22 psi) and it helps me. Perhaps airing down more would be counter productive (not sure about that)

Ultimately there are a lot of people with a lot of conflicting advice and theories. I suggest if your traction is struggling on a Winter road, try letting out 5 psi and see for yourself if it helps. Try normal psi - 5 psi.

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post #11 of 46 Old 02-16-2014, 09:39 PM Thread Starter
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A tire will lose about 1 psi for every 12 F temp drop. So during Winter storms a lot of people are driving around 2 to 3 psi lower than their normal psi, assuming a 30 F temp drop when a Winter storm arrives.

So if that's the case, it's close to the 5 psi drop I intentionally do.

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post #12 of 46 Old 02-17-2014, 06:14 AM
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Quote:
Originally Posted by Charley3 View Post
A tire will lose about 1 psi for every 12 F temp drop. So during Winter storms a lot of people are driving around 2 to 3 psi lower than their normal psi, assuming a 30 F temp drop when a Winter storm arrives.

So if that's the case, it's close to the 5 psi drop I intentionally do.
True, although some of us air back up to compensate for it. For onroad snow conditions airing down is not good advice.

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post #13 of 46 Old 02-17-2014, 06:31 AM
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Quote:
Originally Posted by Wheelin98TJ
A better analogy would help make your point stronger.

Who drives a Vette in snow? The type of people we point and laugh at.

What types of tires are used on Vettes?
Not to mention its a RWD with a V8...

I don't even own a jeep anymore
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post #14 of 46 Old 02-17-2014, 08:50 AM
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Airing down is for the ones not running winter tires, just because the rubber compound is getting too stiff to comply with the surface, it's all about contact, talking here about snow/ice on road, not deep snow in trails where you would need to deflate more to float, so for the road it can help but not that much, so just removing 4 or 5 psi is enough, not more than that, just to help the contact.


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post #15 of 46 Old 02-17-2014, 03:36 PM Thread Starter
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I was reading at another forum where several people say it helps. One said it helps because a little less air gives a flatter contact patch, longer patch, and causes the outside row of treads to have more contact and dig in more.

That's referring to slightly airing down.

Warning: I often edit my posts a few times to get them complete, or to correct errors.
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