Hi I'm now the proud owner of a 97 V8i Disco which is shod with 245/75/16 BFG Long Trail tyres. This seems to be the largest tyre that can be fitted without modification and it does seem rather close to the bodywork. This size is not listed in the handbook so I don't know what pressures I should use.

The BFG's are prefixed LT before the size 245/75/16 (whatever the LT means?) but the only reference to pressures on the sidewall is for the max load which is 1380 Kgs at 80 PSI cold!!

There is no way I'm pumping these up to 80PSI

but then I'm sure each wheel is not carrying 1380Kgs each

Without a weighbridge I can't tell what weight I have on the front or rear tyres and BFG wouldn't have known what load these tyres would carry on each vehicle model when they moulded the tyres. The correct pressure must surely be related to the weight they are carrying?

The handbook has significantly different pressures for the front and rear tyres in both the 205 and 235 sizes specified, so presumably this would also be true for using the 245 section.

Has any body actually got a recommended pressure for this size?

 

80 psi max is an e rated tire, about 40 seems to

 

80 psi max is an e rated tire, about 40 seems to be a good pressure for the weight of these trucks, but I depends how much weight your are carrying

 

And 245 /75/16 will rub in the rear at full flex with a 2" lift

 

The Disco 1 weighs at least 4500 pounds. I would think that the front axle is carrying more weight than the rear only because of the engine(I could be wrong). Assuming all things equal, that's 1125 lbs for each tyre to carry. So running at near max pressure(I'd say 40-60psi) would not be a bad idea, especially if you are carrying stuff(people, gear, donuts, etc.) It also depends on what you are doing. I always run max pressure in all my vehicles unless I am going offroad.

 

Running half psi does not equal half capacity.

 

Best rule of thumb for an 8 or 10 ply 245 or larger tires is 38 to 40 pounds all the way around.

 

235/70R16 is the OEM size for a DI.
"LT" means "light truck", so LT245/75R16 translates into "light truck 245/75 radial 16" rim."
A "P" means "passenger", meaning theya re for passenger cars and trucks and have a lower weight rating as well as a lower max PSI and of course fewer plies of tread and sidewall.
You have a "E" rated tire, which is a 10 ply tire, meaning 10 layers of rubber which gives it great strength, rougher ride usually, but a better built tire overall.
40psi would be a good all around pressure, I run mine at 35psi.
Run them to soft and they will wear out faster, run hotter and lower your MPG, run them to hard and you will have less contact with the road, they will hydroplane easier in the rain and you will loose snow and off road traction too.
You can play around with the PSI to what works well for how you drive, where you drive and how much weight you carry.
On the farm growing up we ran 10 ply tires and kept them at 80PSI, but the pick up was usually loaded with firewood, hay, or pulling a trailer.

 

Thanks for all the replies chaps.
My thinking is that the optimum presssure will be whatever keeps the tyres correct shape when it is loaded up by being fitted to the vehicle. I note that the standard 205 size tyre has a higher pressure than the 235 alternative and in both cases the rears are significantly higher than the fronts. Presumably because the smaller section will be more deformed by the weight of the Discovery than the 235 and perhaps there is more weight on the rear. If I'm right the 245's being bigger would be less deformed by the weight of a Discovery and so would probably have a lower optimum pressure than even the 235's but I suspect 25 or 26 PSI on the front would be OK and 35ish would be OK for the rear. At the moment they are about 40 PSI all round and the ride is quite harsh. I'm sure the advice here, to experiment is the right course but I'd be happy to benefit from other owners experience. Any further opinions?