Lowest safe tyre pressure

[Adrian123]

If I lower the tyre pressure I always worry that the tyres will pop off. What would be lowest SAFE tyre pressure I could set?

Thanks.

Adrian
HiLux MK8

[martynvella]

Depends where your driving and how you drive

[hiluxxury]

^^ x2

When when we did the Canning, our tyres were at 14psi cold for the 2000kms. Not once did we have a problem with tyres.

We never got above 3rd gear though, most was probably done in 2nd gear.

[taresk]

Also depends on the tyre, and how wide your rim is, some tyres hold the bead better than others.

[LashellBeazley]

The surface of driving groud matters a lot. Usually, for 4*4 wagons and utes, it should be between 30psi and 38psi. I don't know anything about your vehicle model and type as well. Would you like to explain?

[William_Foster]

If I lower the tyre pressure I always worry that the tyres will pop off. What would be lowest SAFE tyre pressure I could set?

Thanks.

Adrian
HiLux MK8

Welcome to the forum Adrian.

A discussion regarding tyre pressures can go on for a very long time, but at the end of the day it depends on the terrain you are travelling on, the speed you are travelling, the drive configuration at the time (gear, low range, high range, 2wd), the weight of your vehicle, and your preferred driving style.

Cooper Tires have got a good brochure on tyre pressures that is worth a read (Reference: https://www.coopertires.com.au/media/14 ... ssures.pdf).

In general just lowering your tyre pressures won't cause your tyre to come off the rim, i.e. if you find a flat tyre on your car in the morning as a result of a slow leak, the bead wouldn't usually break even though it may end up well below 10psi. What generally causes a bead to break is low pressure combined with speed, change of direction and a hundred other variables. As Hiluxxry stated, you can cover great distances over some of the roughest roads in the country with low pressures as long as you are careful and know the limits of your equipment.

For myself if I am about to enter a really boggy section of a track where I think I am at risk of getting bogged I will go into low range, deflate the tyres to 20psi, then go down in small increments if I still have trouble; noting that traction aids like Maxtraxx combined with a mildly low psi might give you enough momentum to get out of a boggy section. I personally wouldn't lower my tyres to 16psi or below as the first option unless I found myself in a really tricky section.

I am sorry if it seems like I am telling you how to suck eggs, but you could consider doing a 4wd training course; they are generally pretty cheap and a great day out. The best bit is that they give you an opportunity to try your vehicle out on a variety of terrains in a safe environment so that you start to feel more comfortable with choosing the right psi for the different situations you might encounter.

Let us know if we haven't answered your question, generally someone on here will be able to help.

[Myralga]

As a good “rule of thumb”

Most old school operators have a few presets that they “look” for and not so much get a reading on the pressure gauge. (At least initially)

Highway: read the specs on your tires an you won’t have trouble.

Good dirt roads: honestly I never change from highway.

Bad dirt roads: this is heavily corrugated and bad washouts etc.
personally If I’m driving this all the time I drop my tires from spec till they just start to bulge. This allows some extra give and if you hit a serious sharp edge or a pot hole/wash out it’s less likely to Pop/blow out.
Note that your going to have a softer ride which means you don’t know what’s happening under you as much. Drive to conditions.
(I have personally been thrown on a maintained shire road from the left side to the right side drain and off into the scrub in a split second just from the skip of corrugations so please drive to the conditions)

Sand/Dune running: This is when you want as much surface area as possible aka the maximum amount of tire touching the dirt. drop your tires as much as you feel is comfortable. Soft side walls don’t need as much as say a really hard side wall mine spec tire. But your looking for maximum bulge here while maintaining some sort of tire pressure. SPEED DRASTICALLY REDUCED.
This is where it’s a bit of a guessing game but always have your aids maxtraxx, shovel, snatch straps, winch compressor etc. Don’t travel alone or at the least travel with an ability to communicate.

Off road rock crawling wanting all that grip:
Personally about half way between sand and bad roads. Tire should have a decent bulge but because rocks are not that forgiving when you drop hard or hit them you still need to maintain some sidewall to protect the rim and prevent splitting the side wall.
This is again about finding a happy medium.
You gain extra grip but with that extra risk of just breaking something deeper. CV diff etc.

Again this is all to do with the look [emoji102] of the tire. Once you have a idea what works then you get your readings and you now have your magic numbers.
But remember they won’t be the same every time you go out so take it as a guide point.

Example if you go play in the dunes with your buddies for the day you might have no weight on so the tires going to have to go a lot lower then if your loaded to the max with half tonne of gear in the back to go traveling through the dunes for a month.

Also remember if you get new tires (different brand, style etc) you will have to get your magic numbers all over again.

And also keep axles the same pressure. It’s ok to have different pressures front to rear but never side to side.

Understand that this is a rule of thumb and a good starting point. But nothing beats a good bit of training. And you will learn how your ute really works in a controlled environment.

I hope this helps anyone coming across this in the future. And I’m sure plenty will disagree with me too.
That’s the joy of everyone having there own opinions.
As a last note don’t stress over it too much and remember to have fun.
I done plenty of mud running and rock crawling at tire specs simply because I’m too lazy to get out and change for 10-20km of driving.



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[Adrian123]

Thanks to everyone for their replies, particularly William_Foster and Myralga. I have a HiLux in the Dominican Republic and no previous off-road experience so pretty much use trial and error and a bit of reading. Main issue is mud.