EVERY 4 WHEEL DRIVER NEEDS TO KNOW THIS 

100% agree. The smaller the rim diameter/tyre wall ratio the more off road ability. Lower tyre pressures and lower throttle means more traction. Mostly we need less power and more tyre. 1 needs brain power, the other needs smaller rims.

I think you're forgetting tires have gotten considerably taller and more available. As you go up in tire size, a small wheel becomes a hindrance, not an advantage. 40s are normal now. Ground clearance is king here. 37 on anything less than a 17 inch rim doesn't give any benefit. 40+ on less than a 17in rim is stupid. A 37 on a 17-inch aired down is on another planet compared to a 31 combination. It's also stupid to run a larger rim than needed, but them folks don't wheel hard anyway.

@@GadsdenJL For most of the overlanding / occasional harder track that we do in Aus, we don't need crazy high tyres. This isn't Moab type country. Really tall tyres completely screw the gearing, and considering the km we do on dead flat roads to get anywhere (often in the thousands km per trip), it makes zero sense, that kind of ground clearance isn't necessary. 4WDs had it spot on in the 1980s with the 70/80 series Land Cruisers, Patrols, Defenders. Any of that period's OEM tyre options work as well today as they did then, the Toyota 8Jx16 (various offsets) were perfect, but my favourites for desert travel were high ply rating 7.50R16 on 6.5Jx16. I ran cross-ply Dunlop Universal with tubes on Land Cruiser split rims for years from one end of Africa to the other, zero problems in terrain and conditions that make me wonder how the hell we ever made it. Mention that in today's 4WD forums and they think you must have been mentally disabled in some way. I've done the whole of Aus inside out and round and round several times over on 7.50R16 radials, all the well known tracks / deserts, zero problems. Mega tall tyres - just not necessary.

@@English_Speaking_Fox Absolutely agree

You are right but I think you can do pretty much anything with 17" wheels. Smaller than that it would be problematic for braking on modern cars especially when weight starts increasing

I don't have beadlocks and consistently run 10osi with no problems

C’ mon man it aint nap time yet!

In the US, we call that effect washboard. I air down to 12psi almost as soon as I hit dirt, and it soaks up most of the bumps in combo with my suspension. It's the worst.

1400 cc's ? So a Harley / Indian / Victory ? Or something like a Suzuki (I think) Calavcade ? I'm an Old rider too . " Chairs " are pretty rare these days .

@@johncunningham4820GSX1400 built for off-road touring.

@@Mouldyturnip75 The Grenadier is the only production vehicle I know of that can display the tire temperatures. I don't know of any aftermarket system that shows tire temperatures either.

@@Mouldyturnip75 Tire temperature or air temperature inside the tire? From videos I seen of the Grenadier it shows tire temperature across the tread section width (inner, middle, outer). Your suggestion that I need to "get out more" is condescending and implies you have a higher opinion of yourself than you rightly deserve.

@@The_Opinion_of_Matt You do get aftermarket tire pressure systems that goes on the inside of the tire and not on your valve.

@@xavierdutoit9496 Yes, I know that. They have been around for years. I have yet to see one that does tire temperature too. Maybe something that shows tire temp is available to club racers for a few thousand, but I haven't seen anything for commuter cars.

@@The_Opinion_of_MattI’ve been using one for about 10 years that does both temperature and pressure

Luckily sand doesnt dent diff covers, eh?

The damage done to a tire from under-inflation can go undetected for months sometimes. But usually if the tire is standing up fairly well you can go short distances at a decent speed. The longer the trip and the lower the pressure the slower I'd go. I can answer your question... Because the people at the dealership/tyreshop are idiots.... hahahaha Seriously though, I have 20 year of working in the tire business and was taught by a 30 year veteran of the same. I learned the right way not the politically correct way to handle tyre pressure and a lot of other things relating to tyres. The most important lesson I learned though was I cant tell anyone how much air they need in their tyres, and no one else can either. I know how to figure it out (chalk test) and can make a fairly accurate educated guess but that is all. That being said, the people setting your pressure are going by what some idiot in an office told them to do to reduce liability, and the sad thing is they are actually increasing their liability in the end by over-inflating your tyres. An over-inflated tyre has less traction and in the right/wrong situation can cause an accident. The placard on the door-jam is actually similar to the pressure information on the sidewall of a tyre, it is the pressure needed for the maximum load of said vehicle, NOT the running pressure that almost all drivers may need. TPMS is really only good if it will accept the realistic pressure you need for your load and driving style. You may need only 32 psi in the front and 28 psi in the rear tyres, but imagine the TPMS freaking out over those pressures. As far as tyre health, 10% over-inflated wont really hurt the tyre other than make it wear down the middle of the tread, 19% under-inflated is the opposite wear but not really low enough to harm the tyre otherwise unless you are driving at racing speeds. Other than the irregular wear the 10% over-inflated tire will have less traction, esp in emergency manuevers/stops.

Split rims and 235/85-16 on my 80 diesel for last 25 years 4x diamond chains for mud, triple locked with ARB lockers and winch driven off gearbox pto front and a manual winch rear. Been pulling out bogans since I was a teenager some 30 years ago 😆

@@superwag634 wide tyers might look tough but in the bush function is the only thing that matters. There's plenty of bogans out there 😁😁😁😁

Yeah but nobody measures the tyre footprint. They measure the pressure in the tyre.

What about this rule, Ronny. I can remember easy rules like this and I don't do any extreme 4WD, so only need a 'rule of thumb' like this. Is it Ok?

Jack the vehicle on level ground, inflate the tire, should reseal the bead around 45psi, keep inflating a bit to be sure, then deflate to desired pressure and carry on. Done it more times than I can count.

TPMS- We begin the day at 46 PSI rear axle, goes to 51-52 driving at hwy speeds We begin the day at 36 PSI front axle, usually sits 39-41 at hwy speeds. Caravan axles at 36 PSI usually sits around 38-41 at hwy speeds also. To my way of thinking 4-6 PSI variation as recommended is acceptable. Going lower for grip off road, we don't notice much PSI increase whatsoever, 25 PSI goes to 26 PSI usually, if speed involved may go to 28 PSI only. We've not noticed a big variance with tyre temps in either on or off road situations. Temps mostly vary by which tyres are getting most sunlight, if travelling at night temps hardly vary but PSI increased remain within 4-6 variance irrespective. TPMS- if monitored gives all the confidence required in most circumstances, ignore it at your peril. TPMS great addition to any vehicle plus van.

Yeah exactly, I have a 1400kg Pajero io and have had a Forester in the past and I found that 40psi is much too high even for highway - it made my AT tyres so much noisier and reduced grip on road. I've found that going from 32psi down to around 21psi when going off road on dirt, mud and rocky tracks quite good, it's also not that much of a penalty in handling on the asphalt and doesn't heat up much but you can definitely notice the difference. I usually pump them up at the nearest service station.