Sliding Backwards

[christensent]

Any tips for avoiding an out of control backwards slide when snow wheeling? I was on Tonga Ridge today and on the final steep section I was in ruts that had been beaten down to ice with a few inches of fresh on top, half way up I started spinning, lost traction, and immediately went backwards. Brakes or hitting the gas only made me go faster, probably hit 20MPH in an out of control slide before I threw it in reverse and then slowed down. Is this proper procedure? I've thought through the scenario before and concluded reverse would be best, and it seemed to work. Is it actually better to just keep gassing it in the forward direction?

[Nobody]

Sounds like you did the best thing possible. Nice job on the quick thinking. I've been in backward slides a time or two, but nothing like that Good thing no one was behind you! There have been many deaths from people getting squished between vehicles. These stories always serve as a good reminder not to linger between vehicles, and to give the person in front of you some room.

Generally, I try to be aware of the ice and slick situations and ensure that I'm aired down as much as necessary to avoid sliding off the mountain. Sometimes I'll get out of the ruts and break new trail. That's not always an option though. The ice has a way of sneaking up on you.

Here's a video I made of some really icy conditions I found myself in. My tires were at 5psi. I wouldn't hesitate to drop to 1-2 psi if needed.



This day, Steve was caught at full air pressure and his hubs unlocked. He couldn't get couldn't get out without his bronco sliding away, had to keep his foot on the brake so all four wheels stayed locked up. I had to come back and lock his hubs.

[christensent]

So there's a confusion I have... isn't airing down actually significantly worse if the conditions are ice or hard compact snow where you don't need flotation? You just decrease the pressure on each tire lug and turn it into even more of a sled is my understanding, which is why narrow small tires are optimal on icy roads.

I once did a comparison on a paved icy road where I could almost safely drive down with street tire pressure, and aired down I could barely even start moving and immediately had rear end slide out. Maybe that was a strange situation and I should try again next time?


This particular slide this weekend was at 8PSI.

[Nobody]

Airing down is significantly better. It has to do with the coefficient of friction and the properties of rubber and what not. It's all over my head. I can say with certainty that 8 PSI is far too high for conditions that slick. Consider that if you had lowered your air pressure to 4 PSI, the contact patch area would nearly double in length. That's a lot more biting edges on the ground. Siping is really critical in these situations too. More biting edges, makes the tire lugs more flexible, and squeegees the surface water away.

I'm not sure why your comparison would have given you a different result.

Good topic btw.

[christensent]

ok... I'll have to go do some more comparisons sometime, plenty of opportunities coming up.

Every time I've been out so far, I've noticed no difference in performance in both deep snow or compact going from 5psi down to 0-1psi so I've just been leaving it in the 5-10 range for improved ground clearance recently.

[Nobody]

You should be seeing a big difference below 5 psi. If not, either your air pressure isn't as low as you think, or the sidewall of your tires is too stiff. What tires are you running?

In this video I couldn't get up the hill at 4psi. Dropped to 2psi and drove out.

[christensent]

Tires are radial c-rated 35 MTR Kevlars so sidewall shouldn't be a problem. Down at 0-1 PSI they visually appear completely flat with the rim a few inches from the ground.

This is what they look like at 7-8PSI, don't have a picture when they're real low.

[Nobody]

Those should do pretty good. Need siping. Are the sidewalls 3 ply? What do you have for an air gauge?

[christensent]

Those should do pretty good. Need siping. Are the sidewalls 3 ply? What do you have for an air gauge?

Yes pretty sure they're 3 ply. I haven't siped them because I also use them in the rocks in the summer but I probably should do at least some shallow surface siping.

Air gauge is just generic 0-60PSI analog gauges on my air up/down tools. They are a few PSI different reading in the 0-15 range so I just average them for rough numbers.

[bobracing]

What do you have for an air gauge?

Yes pretty sure they're 3 ply. I haven't siped them because I also use them in the rocks in the summer but I probably should do at least some shallow surface siping.

Air gauge is just generic 0-60PSI analog gauges on my air up/down tools. They are a few PSI different reading in the 0-15 range so I just average them for rough numbers.

Most 0-60psi gauges also go down to about 3psi and not overly accurate. I'd suggest you get a 0-15 dial gauge, getting down below 10psi, accurate psi ratings are much more critical.

[Nobody]

Most 0-60psi gauges also go down to about 3psi and not overly accurate. I'd suggest you get a 0-15 dial gauge, getting down below 10psi, accurate psi ratings are much more critical.

Agreed. I have a low pressure dial gauge, but prefer the cheap digital gauges. The trick is finding one that reads low pressure.

Here's a write-up I made when I was in search of a new digital guage: http://www.snowtrek.org/low-pressure-ai ... gauges.php

This is the one I'm currently using. Verified low pressure readings against my dial gauge.



This one looks promising. I might order one and test it.



I think the secret to finding the gauges that read low pressure is to look for a tip that looks like this.

[Scoobienorth]

From my experience driving trucks off highway if I start sliding backwards and can't hold it usually best off to push in clutch or find nuetral and steer to back into the high side bank. Either you'll be stopped there or spin around and drive it out forwards down the hill. If you've lost control I'd rather hit going slower than faster. Obviously exceptions do apply. Hard to use broad stroke for wide possibility of conditions.

[christensent]

From my experience driving trucks off highway if I start sliding backwards and can't hold it usually best off to push in clutch or find nuetral and steer to back into the high side bank. Either you'll be stopped there or spin around and drive it out forwards down the hill. If you've lost control I'd rather hit going slower than faster. Obviously exceptions do apply. Hard to use broad stroke for wide possibility of conditions.

Ya, that's always my goal... in this case steering did nothing, went lock to lock and just stayed right in the ruts. On a flat I drove a quarter mile or so with my wheels full lock just for the laughs.

[Nobody]

These guys had a nice backward slide at 5:20