Discovery 5 Tyre Pressure

[mkjadams@gmail.com]

Hello all,

Anyone with any advice for tyre pressures I’m running continental cross contact asx 255/55r20’s and towing 3200kg at present I have 44psi front and 59 in the rear but the car seams a bit floaty, any advice we’ll appreciated
Cheers Mark

[shack]

Hello all,

Anyone with any advice for tyre pressures I’m running continental cross contact asx 255/55r20’s and towing 3200kg at present I have 44psi front and 59 in the rear but the car seams a bit floaty, any advice we’ll appreciated
Cheers MarkAlways handy to have a rough idea of axle loadings before doing tyre pressures, do you have any idea on the weights?

The rears do sound pretty high though, what does the owners manual say for that size?

[ramblingboy42]

at 59psi I'm not surprised its floaty, must be understeering something fierce.....I would not drive any vehicle with those f-r variations.

[FAST]

Always handy to have a rough idea of axle loadings before doing tyre pressures, do you have any idea on the weights?

The rears do sound pretty high though, what does the owners manual say for that size?

Totally agree - must use the axle loads and then go to the tyre load tables which are available online.
Rears seem high, but that will not lead to "floaty", in fact the opposite.
Assume that you have the load correctly distributed and ~320kg on the hitch? Lot of people I talk to put weight on the rear of the rig in order to reduce hitch load, which just leads to high polar moments of inertia and instability that could be described as floaty.

[Numb Thumbs]

I agree with FAST. Those rear pressures are really high.

Have you put the rig, fully loaded, over a weighbridge? That will give you your axle loads so you can work out your tyre pressure starting points by comparing the load on each tyre to its maximum load marked on the sidewall along with its maximum pressure. You can do the math - if the load is half the maximum pressure, try half the maximum pressure. This is just a starting point, not a golden rule.

I have always had faith and used the "4 PSI Rule". Measure the tyre pressures cold, drive for about an hour, then check them again. If the pressure has gone up around 4 psi, your are about right. If less than 4 psi, they are too high, so let a little air out and then do it again. If more than 4 psi, the pressures are too low - the overheating has pushed the pressure up - so put a bit more in and try again.

I have Nitto Trail Grapplers in 275/55R20 so my pressures are not relevant to you, but I use 34 front, 38 rear. I tow under 2 tonne with around 140 kg on the ball and use the same pressures.

Cheers
Numb Thumbs ;)

[trout1105]

Hello all,

Anyone with any advice for tyre pressures I’m running continental cross contact asx 255/55r20’s and towing 3200kg at present I have 44psi front and 59 in the rear but the car seams a bit floaty, any advice we’ll appreciated
Cheers Mark

I could be wrong But isn't 51psi the Maximum inflation rate for these tyres?