Thread: Tyre Pressure? - General Grabber AT2

Originally Posted by grumpybastard

Well i finally have a new set of General Grabber AT2's (255x60x18) fitted replacing the Wranglers (255x55x18) on the D2... Yay!

Now i know a few fellow Aulroians have the same tyres and set-up as me, so im wondering what tyre pressures you are running on the bitumen?

Im hoping it will save me a bit of time messing around finding whats the best pressure ...

When i picked it up with the new tyres it was running 40psi all round, im currently running 35 in the front and 38 in the rear.

Suggestions?

Thanks
Matt

Hey there Matt, good to see you on again.

I normally run the same pressures all round unless heavilly loaded when I bump up the pressures in the rears.

Being GG AT2 Im pretty sure it should be 10 ply so they should be pretty right at about 35 to 40 and about 18 to 20 off road.

Just a quick question, did you get them through Jamie?

I think where you are on road is on the money. Offroad I'd be very careful under 25psi not to damage the rims.

I ran mine at 32 on the front and 46 on the rear but would drop them to 42 on the rear if I was running empty....

28/48 as per the placard made the front to squirmy for my liking and every bump i hit felt like it was going to launch the tail when I was empty.

on the sand (beach sand not hard pack) Id drop straight to 15 (but I carry a compressor and have the spare at 80psi with a hose that would let me cross inflate yes the spare at 80 has enough wind in it to bring the 2 fronts up over 30) use 12psi as the emergancy soft setting but they will stay on at as low as 8psi so long as your not giving it too much right boot.

stay under 40Kph if your pressures are under say 20ish psi

I'm looking at these and would love to see a pick of your rig with them on.. Any chance of a photo to help me decide?

Bridgestone conducted a study in to this and from memory they found that generally in Australia the Tyre placard on the vehicle +10% was about right. (Not including specialty tyres of course, these were based on LT construction AT tyres)

Originally Posted by Blknight.aus

I ran mine at 32 on the front and 46 on the rear but would drop them to 42 on the rear if I was running empty...

Have asked this before, but I can't see why you would run higher pressures in the back when it is empty. After all, the front has plenty of weight in it all the time (engine and front seat passengers) whereas the rear, is empty more often than not. Even when loaded, the rear is not often that much heavier than the front.

I run 35 psi (245kpa) all round for highway use, and do increase pressure in rear by a few pounds when loaded or towing. Unlike some, I am a believer in reducing pressures (and speed accordingly) on gravel roads.

Originally Posted by Blknight.aus

I ran mine at 32 on the front and 46 on the rear but would drop them to 42 on the rear if I was running empty....

28/48 as per the placard made the front to squirmy for my liking and every bump i hit felt like it was going to launch the tail when I was empty.

on the sand (beach sand not hard pack) Id drop straight to 15 (but I carry a compressor and have the spare at 80psi with a hose that would let me cross inflate yes the spare at 80 has enough wind in it to bring the 2 fronts up over 30) use 12psi as the emergancy soft setting but they will stay on at as low as 8psi so long as your not giving it too much right boot.

stay under 40Kph if your pressures are under say 20ish psi

That would be about 15PSI from max inflation pressure on most LT tyres which is normally around 65PSI.

I have heard of people doing this before but I have heard of tyres separating without doing a turn off the wheel carrier after sitting for months/years with those sort of pressures in them.

Originally Posted by numpty

Have asked this before, but I can't see why you would run higher pressures in the back when it is empty. After all, the front has plenty of weight in it all the time (engine and front seat passengers) whereas the rear, is empty more often than not. Even when loaded, the rear is not often that much heavier than the front.

I run 35 psi (245kpa) all round for highway use, and do increase pressure in rear by a few pounds when loaded or towing. Unlike some, I am a believer in reducing pressures (and speed accordingly) on gravel roads.

Im with you there Numpty 100%

My Disco handles much better with even pressures in the tyres and I get great wear out of my tyres.

When loaded you do need to bump them up a bit but generally even with the tent on the roof I have them around the 35-40 range depending on where Im going and what Im carrying.

GB has been in my Disco with softer than normal tyres trying to keep up with Hiline coming down from Tolmie and saw how much it squwirmed around on the road with around the 28PSI in them.

empty is figurative given I carry a fair swag of stuff all of the time my empty is significantly heavier than other peoples empty.....

and Im aware of the 80psi causing tread seperation issues but since I work in a workshop with a balancing machine and heavy duty hoists my tyres enjoy 5k Km rotations. so that pressure is only every in any one tyre for 3 months or less.