Thread: Tyre pressures, front to rear?

heed the tyre manufacturers again

Er , I think you may have missed the point . We are not talking about tyre manufacturer recommendations. We are talking about vehicle manufacturer recommendations. While it is arguable that manufacturer recommendations may be too low and they emphasise ride probably more than handling in the ride/handling compromise, the vehicle manufacturer recommendations are a good starting point, and always backed by research.

I googled as you suggested but found no firm info other than all the tyre companies recommending that the tyre placard is a good starting point, and none on the Advanced driving sites.
Perhaps you could educate us .
Regards Philip A

hi pedro,
i have always run mine at the book pressures, although if not loaded, would drop the rears a couple of pounds.
mostly it's loaded.
when i picked duggy up in steak and kidney the tyres were at 40, as the previous owner said he always ran 4wd tyres that hard.
i drove it 200 km to my first fuel stop.
it drove like it was on a skating rink, apsolutely unpredictable front wheel directional control, i thought a wheel alignment was in dire need.
anyway when i stopped for fuel i dropped the pressures to book figs for the larger tyres, 26 / 34 i think,
it drove like a new car, comfort levey was way better, road holding was like it should be, land rover race tuned suspension, and i still run those pressures today.
i just went to bris vegas today and back today, and although the tyres are now really close to their useby date, it steers like a two ton race car,
given that it is being driven by a nutcase with a right foot used to 8 cylinders of raw power and duggy has half of all that,
the drivers side floor is getting closer to the ground each day

Pedro, I did when I first got the D2a ... but it seemed a bit strange to me ... and after a bit of research I was reccomended to go 10% above the tyre placard. I've always run my tyres a litttle higher than rec', but 10% over in the rear unloaded is too harsh ... but the 10% over in the front (33psi) feels good ... new front tyres help too. I ended up dropping the rears to 36psi for daily driving (up to 5 people) and up them as more load is added.

You might also note that the front tyre pressure rec's are different for a D2 (28psi) and a D2a (30psi) ... the rears are them same.

Kev..

I run 235/85 on my Disco. Does that make a difference? Should I try Defender pressures (defender size tyres, rough weight)

What are Defender pressures?

Remember,all D2's with 16" rims came out with Michelin XPC's.The pressures on the tyre placard give the best ride & handling from the OEM tyre's.They don't give a rats about fuel economy or tyre life.
I always ran the XPC's at around 32 to 34PSI all round & found no problems & also got over 80k a set.This was unloaded.

I have just replaced a set of BFG A/T's on the D2a i have now & they did over 80k as well.These were generally run at around 36 to 38 psi,& 40 on a run.If pressures were run any lower,the A/T's ran very hot.

The worn BFG's would have gone longer,had around 5mm of tread on them,but were very badly chipped & cracked,i think from age.I was doing a long trip in remote area,so decided to replace them.

I always rotated them every 10k.

Just my 2 cents worth

I thought the vehicle placard was based on OEM tyres which were HTs, so relatively low and biased towards on road handling. I'm running my ATs on 32 front and 36 rear and it feels good.

I read something about this years ago. The reason for the pressure difference is to promote higher speed stability into the discovery.

From my experiences in developing them, the rear of them needs roll control, especially as the ride height comes up otherwise they become unstable and twitchy. I think the lower front pressures is to make the initial turn in not too sharp as it is hard to make the rear perform as well as the front in that part of the turn especially as the weight shifts.

When I bought my last set of Michelins (99V8 D2), the tyre shop (Jax) told me that 40 psi all round was ideal. Nevertheless I have always used 32 in the front and 38 in the rear unladen and 48 psi fully loaded with the van. I changed the rear tyres first time at around 90,000km and the front a little later, but they might have been rotated before I bought it. The second set I replaced at 180,000 km together. I personally find 40 psi in the front gives a harsher ride and less impressive braking and steering than the lower pressure.