When NOT to air down?

[jeepstertim]

I had never aired down my tyres prior to jeeping in the sand here in Qatar and the difference is night and day. I have driven off-road for 30+ years but it something we Brits just don't seem to do in the UK.

So my question is, is there any off road situation where airing down is not going to help me?

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[DailyMoparGuy]

Since the vast majority of this forum is sleeping right now, I’ll answer your question as a beginner in off-roading…maybe. Airing down your tires increases the surface area of your tire that contacts the terrain. From a physics and engineering standpoint, I cant imagine an off-road situation where that isn’t preferred other than high speed off-roading. The reason that low pressure in tires isn’t preferred on pavement during regular street driving is heat which comes with highway speeds. It also effects handling. Both of which are also important during high speed offroad excursions.

Now to what degree of airing down for specific situations is another story…ie sand at 16 psi, mud at 22psi, or rock at 12 psi, etc. I have no idea.

I’m sure someone will correct me or dive into this further though. Cheers.

 

[KWin]

Coming from a track background even "race cars" air down before events, compared to daily driving pressures. (Not nearly as much as offroad youtube videos have me believing)

 

[jeepstertim]

Since the vast majority of this forum is sleeping right now, I’ll answer your question as a beginner in off-roading…maybe. Airing down your tires increases the surface area of your tire that contacts the terrain. From a physics and engineering standpoint, I cant imagine an off-road situation where that isn’t preferred other than high speed off-roading. The reason that low pressure in tires isn’t preferred on pavement during regular street driving is heat which comes with highway speeds. It also effects handling. Both of which are also important during high speed offroad excursions.

Now to what degree of airing down for specific situations is another story…ie sand at 16 psi, mud at 22psi, or rock at 12 psi, etc. I have no idea.

I’m sure someone will correct me or dive into this further though. Cheers.

Yes, happy with the logic and boy does it work on the sand. Snow? Most winter wheel set ups I've used (stationed in Germany) tend to be far narrower than their summer equivalent - but is this trying to increase ground pressure on the hard surfaces a car would drive on?.

 

[Sespe]

Yes, happy with the logic and boy does it work on the sand. Snow? Most winter wheel set ups I've used (stationed in Germany) tend to be far narrower than their summer equivalent - but is this trying to increase ground pressure on the hard surfaces a car would drive on?.

I think with snow the idea is to increase ground pressure, period. Either on or off road. When in the Army at Fort Drum, New York (a snow hell-hole), we had both HMMWVs and CUCVs (think Chevy Blazers). There were rating levels for when each vehicle needed snow chains. The HMMWVs, with their light ground pressure, needed chains almost all the time, the older Blazers would still run.
And we never aired down back then.

 

[DailyMoparGuy]

I think with snow the idea is to increase ground pressure, period. Either on or off road. When in the Army at Fort Drum, New York (a snow hell-hole), we had both HMMWVs and CUCVs (think Chevy Blazers). There were rating levels for when each vehicle needed snow chains. The HMMWVs, with their light ground pressure, needed chains almost all the time, the older Blazers would still run.
And we never aired down back then.

Yup I agree. The narrower the tire, the greater the pressure from the vehicle weight to the snow which will help cut through it. Deep, packed snow may be another story though….

 

[fun2drum]

I definitely air down on the soft NC beach sand, and I simply won't get on the sand without doing it. I've seen some impressive looking trucks with big tires sitting on their frames in that sand because they didn't air down. I think it's just as important as shifting into 4wd.

As for snow, I've done a lot of driving in NC mountain snow - which can be some of the most tricky out there due to the steep hills and icing that regularly occurs under the snow surface. Sometimes the ice can be brutal, and it's covered by snow so you can't see it coming. Studded tires do best on that, but they're annoying as heck when there's no snow. I've typically driven 4wd or AWD on relatively narrow all season tires and they've done surprisingly well. I think it's because of the downward pressure combined with the surface area of a less agressive tread on the ice below. I've never really paid much attention to PSI in snow before now.

I've got a feeling that even with my snowflake rated Wild Peak tires, I'll have to be more careful on snow and ice since they're wider and have a more agressive tread. I didn't get much of a chance to try them out last season because we didn't get much snow here and I didn't spend any time up in the higher elevations like I usually do. Anyway, I've also been wondering if airing them down or keeping full pressure would be more appropriate in NC snow and ice.

 

[VolatileA]

Coming from a track background even "race cars" air down before events, compared to daily driving pressures. (Not nearly as much as offroad youtube videos have me believing)

I can confirm the airing down at the race track but mainly because the heat from hard braking, the tires end up with substantially increased PSI as a result.

 

[TwelveGaugeSage]

Yup I agree. The narrower the tire, the greater the pressure from the vehicle weight to the snow which will help cut through it. Deep, packed snow may be another story though….

This is something that doesn't get talked about enough in the Jeep world. Narrower tires are better any time you don't need a lot of flotation, like deep snow or sand. Everybody wants that wide tire look. It's really unfortunate, because I would love to have some decent options for narrow tires. 12.50 isn't terrible on 35s and 37s, but damn I sure wish someone made some 10-11.50 MTs other than Interco.

 

[Maximus Gladius]

To answer the OP, when NOT to air down…
When losing traction isn’t an issue. Airing down is to gain more traction when getting stuck or slipping off your surface is your problem. If this is not an issue or worry, don’t air down.

 

[Fouts]

I will typically air down as soon as we get to the mountain trails. Less air also helps smooth out a bumpy/ rocky road, helps the suspension work much better. Don't do much/any sand but mountain snow is definately better aired down. I will run as low as 5 psi in heavy snow. Back to previous posters coments it will almost always help in limited traction situation except ice.

 

[Beemer533]

To answer the OP, when NOT to air down…
When losing traction isn’t an issue. Airing down is to gain more traction when getting stuck or slipping off your surface is your problem. If this is not an issue or worry, don’t air down.

Don't forget that traction isn't the only reason to air down. Even if you are just trail riding and not necessarily concerned about losing traction, airing down a bit gives you a much smoother ride.

 

[Terminus33]

If you absolutely need more ground clearance over traction then don't air down. Or if you don't have a means to air back up when returning to the road, then don't air down. Those are the only two things I got. Lol.

 

[FitfulGoat]

Speed is another factor. If you are off-roading and expect to sustain substantial speeds with tight cornering you do not want to be running 15psi.

This is why trophy trucks are typically around the 28-35 psi range.

If you have a reliable way to air back up and you will be navigating slow rock gardens or slippery surfaces I would say airing down is almost always an advantage. Especially in the comfort aspects.

@TwelveGaugeSage this 100% we need more skinny tire options. I am running the 35x10.5 Kenda’s and love them.

 

[TwelveGaugeSage]

@TwelveGaugeSage this 100% we need more skinny tire options. I am running the 35x10.5 Kenda’s and love them.

I'm so torn on those. I like the look, I'm just not sure how I feel about going to a 34" R/T as opposed to a 35" M/T.

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