Landcruiser (100/80) tyre pressures

Submitted: Tuesday, Jul 05, 2005 at 17:52
ThreadID: 24458 Views:14042 Replies:6 FollowUps:6
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Running on the standard tyres, the handbook recommends 32 psi for 275/70/16. Not talking about off road here. I use these standard tyres for running about town and going up & down the highway, towing. Even for towing they stick with their 32 psi recommendation. Seems very low to me. Next purchase will be some steel rims and tyres (ATs probably) what pressures are advisable on these, on road. Oddly enough I find it easier to judge off road pressures. Perhaps I've just been caught on the hop with these standard pressures/tyres.
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Reply By: Nudenut - Tuesday, Jul 05, 2005 at 18:10

Tuesday, Jul 05, 2005 at 18:10
i run 36 on mine but i am carrying tools and wear seems great...
AnswerID: 118960

Reply By: Steve - Tuesday, Jul 05, 2005 at 19:48

Tuesday, Jul 05, 2005 at 19:48
Cheers Nud. Just had it serviced for the first time by my usual mechanic. He reckons 40 psi for around town is more like it. Feel more like a compromise meself nearer to your pressures, with maybe 40 on the rear when towing.
AnswerID: 118976

Follow Up By: Member - Jeff M (WA) - Tuesday, Jul 05, 2005 at 22:11

Tuesday, Jul 05, 2005 at 22:11
Absolutally, I even run 40psi in my Work car (Toyota Echo!!).

I run the 31" MTR's on the surf betwen 40 and 44psi depending on load for on road use.
FollowupID: 374176

Reply By: BenSpoon - Tuesday, Jul 05, 2005 at 20:47

Tuesday, Jul 05, 2005 at 20:47
I usually run 40-42 in mine, but on the recommendation of another club member I am running 52 on my MT/Rs. They are running quieter, seem to be tighter on the road, and I certainly have not noticed any ill effects. I am told this is the only solution a few club members found to prevent rubbing off the outside shoulders of tread blocks (which is generally associated with under inflation), as I have experienced.
AnswerID: 118991

Reply By: 120scruiser - Tuesday, Jul 05, 2005 at 21:31

Tuesday, Jul 05, 2005 at 21:31
Have run 32 front and 34 rear on road and so far have 47k out of BFG A/T's and still have heaps left. When out bush I usually drop to 28 all round. No punctures.
Thats on an 80 series.
AnswerID: 118999

Reply By: Steve - Tuesday, Jul 05, 2005 at 21:53

Tuesday, Jul 05, 2005 at 21:53
cheers guys. Think I'll experiment between 36/40 ish. Ben: when you say "tighter" I take it you mean more grip? Although I'd've thought lower pressures would give more grip.
AnswerID: 119003

Follow Up By: Member - Jeff M (WA) - Tuesday, Jul 05, 2005 at 22:15

Tuesday, Jul 05, 2005 at 22:15
Lower pressure mean the tyres suirm all over the place and have less grip, it also means the middle of the tyre is not contacting as well.

I also learnt in my driver training course ( and it makes sense ) that in the wet higher pressure are a good way to prevent aqua plaining as the tyres are shaped in such a way as to cut through the water instead of floating on top of it.

I've always found higher pressures make even the littlest of cars perform and feel much safer on the road. (and I have been known to drive like a mad man in some of these little cars).
When you throw a car around a corner at high speed with soft tyres they roll onto their sides, do it with hard tyres and they stay in shape.
FollowupID: 374178

Follow Up By: BenSpoon - Wednesday, Jul 06, 2005 at 14:57

Wednesday, Jul 06, 2005 at 14:57
IMHO, Tighter= more responsive. They hold a straight line a little better (I have a few inches of lift and no castor correction so it has been a drama in the past) and they seem to take corners a little nicer. Before it was a case of turn the wheel, car starts to turn, then the body roll kicks in as you round a bend. Now its more turn the wheel and the body roll follows straight after- there is no delay anymore.

Its hard to describe I guess, but I'll be sticking with the higher pressures until I see a downside, like excessive wear in the middle or something else. As always, if you are going to put the pressure up, check the sidewalls for the max safe pressure, and consider/test effects of temp and load on the pressure.

Re sticking to the car's placards (post below)... I dont believe my placard states anything about over diameter and width tyres and how to improve handling with a lift kit., hence the experimenting.

Just cast your mind back to the days of buggy factory suspensions in Falcons- when ford came out saying "Drop your pressures to give a smoother ride" With the bodyroll I've got, I dont need anything adding slop to my steering.
FollowupID: 374257

Follow Up By: Member - Jeff M (WA) - Wednesday, Jul 06, 2005 at 15:08

Wednesday, Jul 06, 2005 at 15:08
Actually there's another common misconception too.
People who say crap like "don't pump your tyres up to much when it's hot, cos they'll blow out".

Higher pressures are better for hotter tempetures. ie if your driving up north on the highway a higher pressure is going to give you LESS chance of a blowout.

Reason being:

Grab a bit steel fence wire. Then bend it. Bend it back. Bend it again. Do it over and over and see what happens. What will happen is it will get REALLY hot then snap.

That's what the sidewalls of your tyres are doing everytime they come around and make contact with the groud. If the tyre pressure is low, the sidewalls bend (so does the steel belt). Then it leaves the ground and straightens. How many times a second do you reckon that's happening at 110km/hr!!?? Higher pressure = less bending.
FollowupID: 374260

Follow Up By: BenSpoon - Wednesday, Jul 06, 2005 at 17:36

Wednesday, Jul 06, 2005 at 17:36
True. I once came across a bloke whilst I was living in karratha that had that- He had blown 2 tyres on his mazda sedan previously from what I gathered was underinflation, and he figured if he tried a lower pressure still it would fix it.
He attributed it to heat build up from driving on the hot road. I figure its pretty simple- hold your hand over your tyre after you've done 100km. If its roasting, you've got something amiss.

For a tyre to blow out from excessive pressure, I reckon it would have to de a defect, or a ridiculous pressure in the tyres, considering most people run on 40 odd, and safe pressures are often up to 65 odd psi.
FollowupID: 374295

Follow Up By: Steve - Wednesday, Jul 06, 2005 at 18:31

Wednesday, Jul 06, 2005 at 18:31
65????? Jeez, that's twice the handbook figure on a '98 LC100.

I'm going up to the Whitsundays in about 6 weeks' time. Towing 1.5/1.6 ton van with ride bars. Normally do around 100/110 kph wind and rain permitting. Do you reckon the ride bars equalise the load sufficiently to have the same (say, 40 psi?) pressures front and back. It's about 4,000 ks return, towing, so would like to get it right or near as.
FollowupID: 374306

Reply By: Steve - Wednesday, Jul 06, 2005 at 08:57

Wednesday, Jul 06, 2005 at 08:57
Well I never. I've always dutifully followed the handbook. Thought I'd be pushing my luck increasing by more than a pound or two (psi). I'll be weaving all over the place today to see the difference;)
AnswerID: 119061

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