Adjusting tire pressure for tough underground (4:47 video)

mrctggs

New Member
Hello guys,

this is my first thread here :)

I would like to show you this video which shows how simply deflating the tires of a truck can help driving through snow (as shown in the video), sand (desert), mud etc.
The video was made in Austria and I think it is remarkable how the truck doesn't need any snow chains whatsoever. Unfortunately, I cannot post a video link as this is a brand new account. The title of the youtube video is "Toyota Land Cruiser Snow off-road without snow-chains".

What do you guys think? I guess every army in the world faces problems in difficult terrain. Any experiences?

Looking forward to hear about your thoughts!
 
Last edited:

gf0012-aust

Grumpy Old Man
Staff member
Verified Defense Pro
It's a common trick used by 4wd owners. you can buy tyre deflaters for your tyres at most 4wd shops to take your tyres down to a certain level for sand driving etc. usual preset is 15lbs.

I have them on one of my 4wd's as well as an onboard compressor to reinflate when I unbog myself

most military tyred trucks have tyre deflation/inflation systems. Unimogs have them as standard equipment
 

mrctggs

New Member
  • Thread Starter Thread Starter
  • #3
It's a common trick used by 4wd owners. you can buy tyre deflaters for your tyres at most 4wd shops to take your tyres down to a certain level for sand driving etc. usual preset is 15lbs.

I have them on one of my 4wd's as well as an onboard compressor to reinflate when I unbog myself

most military tyred trucks have tyre deflation/inflation systems. Unimogs have them as standard equipment
Mind telling me which system you are using? Does it use electronics as well?
 

gf0012-aust

Grumpy Old Man
Staff member
Verified Defense Pro
I use manual deflaters - Staun brand. you screw the deflator (its like a big valve dust cap) - the deflater is preset, so when you screw it down your tyres deflate to that preset pressure. it literally takes less than a minute to do by hand. soft sand is usually 12-15psi, any lower and you run the risk of rolling your tyres off the bead - which is why some people use beadlockers.

in australia its illegal to run beadlockers on street/road registered vehicles, they are meant to be used for racing vehicles only. however, some people run internal "soft" beadlockers as they are invisible and undetectable. external beadlockers are obvious as they are multi bolt rings which clamp to your wheel rim to prevent bead roll off

the air compressor is 12v, the deflaters are manual
 

mrctggs

New Member
  • Thread Starter Thread Starter
  • #5
I see. But the inflating of the tires then takes a lot of time I guess? Due to the cross section of the valve being the bottleneck, the compressor can't inflate the tires as fast as it theoretically could.
 

gf0012-aust

Grumpy Old Man
Staff member
Verified Defense Pro
I see. But the inflating of the tires then takes a lot of time I guess? Due to the cross section of the valve being the bottleneck, the compressor can't inflate the tires as fast as it theoretically could.

not at all - double piston compressors make short work of it - onboard compressors for integrated tyre inflation systems such as the unimog and bushmaster can do each tyre in tens of seconds or low single digits per tyre even if totally deflated

on military vehicles integrated on board systems exist to also enhance the safety of the passengers if they are in a threat environment
 

gf0012-aust

Grumpy Old Man
Staff member
Verified Defense Pro
I see. But the inflating of the tires then takes a lot of time I guess? Due to the cross section of the valve being the bottleneck, the compressor can't inflate the tires as fast as it theoretically could.
I run 32" x 11.5" x R15's

from 15psi to 40psi using a double piston compressor takes me less than a minute per tyre

if I ran an "endless air" on board system that runs off a converted air conditioning compressor I could halve it.

small cheap air compressors sold by your average ebay shop are useless, they have poor duty cycles and get slower with each tyre. the minimum capability should be a 100% duty cycle, then its about max PSI, quality of fittings, single or dual pistons, quality of connectors, hoses, gauges, servicability, size of onboard tank etc.... that being said, any well built "endless air" installation using a Sanden compressor will be cheaper but better than the most expensive portable 12 system

like anything, spend the money wisely after doing proper research and you get what you paid for.

military rated on board inflation systems are an order of magnitude better.
 
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