Tyre pressure too high?

[JerraD4D Lurker Find all posts View Profile Close JerraD4D]

Hmmmm. That threat was a good read. I'd concur that there is perhaps no perfect answer; or rather what works for some simply doesn't for others. But for what's it worth, I run BFG ATRs on the 150 and although they are quite new, I have found 38-40 psi to be a good start point. When I picked the car up from the tyre centre (only a week old at that stage) they had inflated the tyres to 48 psi! Well, after a bit of experimenting 40 seemed OK. Anyway, math is not my strong point, so 38-40 = road; 26-30 = dirt / coarse gravel and 16-20 = sand. I'll wait and see how they wear, but even on my last 4x4 tyre dealership was adament I needed to add about 6 psi on recommended inflation level due to change to LT versus passenger.

[butane8 Avid PP Poster! Find all posts View Profile Close butane8]

i am running MT atz (5rib) on a 120.. 43psi front , 41 psi back ...
but i use the scruff marks on the tyres to maintain the right pressure under different loads, and different usage...

i could nearly go 1 psi higher in the front.. and one lower in the back. for scootin' around town .
. the pressure i run suits the towing set up of the vechile... on the open road. i load my rig up so differently every trip that i look at the scuffs to see how its travelling .. those numbers suit my setup and the way i drive... cheers butane,,,

[butane8 Avid PP Poster! Find all posts View Profile Close butane8]

Thats interesting I thought most people had the back higher than the front, what's your reason for having the front higher?

guess it's lighter in the back than the front .... reading the scuffs.... butane

[Anth120playdo Banned Find all posts View Profile Close Anth120playdo]

Thats interesting I thought most people had the back higher than the front, what's your reason for having the front higher?

Rear pressure should only be load dependant.

Front does steering/cornering most of the braking, add they are also drive wheels, they tend to be able to roll more, therefore can cause edge wear, using higher pressures in he front help reduce this. Slowing down on bends/turns will help a lot more. Higher pressure in the front will support the tyre more in emergency braking, more braking pressure/stopping traction before the wheels lock up or abs kicks in - braking increases load on front, reduces load on rear.

Don't overdo it, more air = less footprint, and less traction, not to mention a much rougher ride.

[AJ120 Out of control poster! Find all posts View Profile Close AJ120]

Thanks that makes sense.

I'm happy with my front pressures but you have made me think about my back, I might try reducing it to see if it feels better.

Thinking about it though, on a long drive it will change a lot as you burn off 150L of fuel.

One of the fuel tanks is behind the axle, so burning that will reduce load on the rear, the other is between the axles so will reduce weight on all tyres. Rarely would you use the full 150 lts, so your probably only talking 100kg or so of fuel burn from full to refuel time.

Given the wide variety of opinions on what is a good pressure just in this thread I think people can get a bit carried away with adjusting pressures for changes in weight. Would you change your tyre pressures if 2 adults sat in the back seat? Probably not, so a bit of change from fuel burn is no big deal.
Sure if you normally run empty and then load up the back, fill up the roof rack and pile the family in a few extra PSI is a good move, but not for minor changes.

Cheers Andrew

[butane8 Avid PP Poster! Find all posts View Profile Close butane8]

One of the fuel tanks is behind the axle, so burning that will reduce load on the rear, the other is between the axles so will reduce weight on all tyres. Rarely would you use the full 150 lts, so your probably only talking 100kg or so of fuel burn from full to refuel time.

Given the wide variety of opinions on what is a good pressure just in this thread I think people can get a bit carried away with adjusting pressures for changes in weight. Would you change your tyre pressures if 2 adults sat in the back seat? Probably not, so a bit of change from fuel burn is no big deal.
Sure if you normally run empty and then load up the back, fill up the roof rack and pile the family in a few extra PSI is a good move, but not for minor changes.

Cheers Andrew

that pressure is what i use all round , normally my rig gets filled up to the hilt with juice( 98 ) and loaded up with a decent trailer , full of deliveries for the farm.
i come home with a empty rear tank , empty trailer and no food or grog, in the rig....... then i use the rig for a toy around town till i finish maintaining it for the next road trip .. once a month it happens...
but the tyre pressure's i run, empty or full ( load ) havent change since the purchase of the mickey thompsen's atz"

evan in winter i may up the setting one pound , because of the scuff, and i do! but the tyre scuff's will tell you what the brand of tyre to the weight you run ... the pressure it like's , front and back , dont be scared too play around with how the scuff works , under pressure change...

just stay away from round abouts and hard corners when reading test scuff's under pressure changes the best bet is to spray some trye shine over the corner, of the tyre, and take it for a quik drive , drive normal.

the scuff's will stand out , then you will know what to look for under different load conditions.... cheers mate butane

[MalG Lurker Find all posts View Profile Close MalG]

I ran my factory fitted Grandcraps at the recommended 29psi and found that I was getting bad wear on the outside after only 16k kms. I had the alignment done and upped the pressure to 38 after reading the blog and noticed that the wear had not increased except for the front left tyre. The wear was so bad that the tyre needed replacing. I bought a new tyre and changed the other front tyre with the never before used spare so as to even up the front tread. I then noticed the front left tyre wearing on the outside again and asked Toyota to do the wheel alignment as I was sure this was to blame. They did the alignment and the Service Consultant said that it was not the issue but that Prado's wear more on the left as they are heavy and also blamed round-abouts! Now, I have driven many and various fourbys over the last 20 years, from Landy series 2 & 3, 110's, Disco's and a Toyota Trooper the length of Mozambique, and have never heard such a load of crap. Anyone?

[Corigator Avid PP Poster! Find all posts View Profile Close Corigator]

MalG
My front left certainly wears out quicker than the others. It may be round-abouts but driving on the left means that every trip will be a circuit with more left turns than right. Perhaps the left side of the road is a little rougher also.

Not really sure of the reason but it certainly does wear more on the front left. I rotate the spare on the left as well, so that evens the wear.

[Hutch Addicted PP Member Find all posts View Profile Close Hutch]

MalG, If u have a 120 that is certainly the case mine was the same and many more like it that I now of, however my 150 isn't the same though don't have any issues with it.


Hutch- 2012 Prado 150, some TJM Kit.

[AJ120 Out of control poster! Find all posts View Profile Close AJ120]

Cant say as I have ever noticed extra wear on the left front of mine, but then again I'm not a city slicker going round roundabouts all day long either

Cheers Andrew

[jss Moderated member Find all posts View Profile Close jss]

My grandcraps are nearly stuffed with 30k on the clock. The outside edges are trashed because where i live is roundabout city. I'm running about 44-46psi cold just to try and get some better center wear. But on the up side in another 5k i'll be getting some better rubber. i'm thinking Pirelli Scorpians should do nicely.

Cheers
James

[mjrandom Out of control poster! Find all posts View Profile Close mjrandom]

My grandcraps are nearly stuffed with 30k on the clock. The outside edges are trashed because where i live is roundabout city. I'm running about 44-46psi cold just to try and get some better center wear. But on the up side in another 5k i'll be getting some better rubber. i'm thinking Pirelli Scorpians should do nicely.

Cheers
James

Caloundra?

[jss Moderated member Find all posts View Profile Close jss]

Caloundra?

Pelican Waters. I go through 4 just to go to the local shop which is probably about 600-700 meters. 7 to get out of pelican one way and 9 to get out the other. Roundabouts suck.

Cheers
James

[yowie Advanced Member Find all posts View Profile Close yowie]

Drive over them (if no cops about)

[mjrandom Out of control poster! Find all posts View Profile Close mjrandom]

Mate lives there off Sir Joseph Banks Dr. It gives me the absolute shits driving there and back. We were there on Friday night.

I think roundabouts do contribute to the wear and rotating tyres is the only way to address it. The other thing is the Dunloops are soft in the sidewall.