Tyre pressures for on road driving - 2004 110

[Mellow Yellow]

G'Day All,

I recently put a set of BFG Mud Terrains on Peril and didn't check what the tyre guys had put in them them until I went off road recently and aired down.

They had put 36psi in the front and 45psi in the rear (might explain the harsh ride unladen around town!).

On the front is a winch bar and winch. At the rear is a cargo barrier, tow bar, 160 litres fuel tank (half full around town), two auxiliary batteries and a drawer system (empty around town). On top a full length Rhino Rack.

The Defender hand book says 28psi front and 48psi rear under all conditions. I find this odd as :-
(a) the rear is 20psi higher than the front.
(b) the load is typically only the driver and not much else or loaded up with a passenger, frig, recovery gear, spares, tools, camping gear, full fuel tank, food, clothes, etc and towing a trailer - so why not an unladen recommendation and a laden recommendation?
(c) 48 psi is very high in my experience.

I would have thought 32psi in the front whether laden or unladen. For the rear, 36psi unladen and 40psi laden.


I'd appreciate knowing what tyre pressures others run (and why)?

Ta!

[Fraz]

I have a 130 with BFG ATs (soon to be MTs :)), and I put 40 psi in front and rear, as they look flat when sitting there - unladen.

When doing bigger trips with alot of gear in the back, Ill put the back to 45psi, which improves the ride considerably. It doesnt feel like jelly, and they look just as they would when unladen.

Ill be interested to see what others use though, and how different these pressures are for 110 v 130.
Fraz

[stig0000]

i have 265/70 i think:wasntme: MTR muddies,, and run them at 35 allround,, and do a rotate balance and alingment every 5k, all of them are wering perfict, iv done just on 25k i recon with the muddies, and with alot of 4wding and road driving and still no were near half worn:D, i cant be more happy, im expecting 60-70k easy out of them, ;)

[Psimpson7]

I run 255/85 r16s BFG MT's at about 32psi front and rear

[dmdigital]

Towing the Kamper on sealed roads I run my rears at 64psi and fronts at 40psi

Off road I drop them to 28psi when towing. Or less if conditions dictate.

Normal daily drive 32psi all round. 45psi rear if loaded up.

I'm still running the General Grabber TR's on the Boost alloys on the Puma.

My Tdi I run at 32psi normally - Cooper ST's (I think they left two letters out of the ST:angel:) on steel rims.

[Blknight.aus]

big red runsBFG AT at 32 front 42 PSI for round town work.

36 46 if Im going to be doing sustained periods of 100Kph plus or If Im loaded to near GVM

32 46 if I have the trailer on for an extended trip

40 50 if Im going to be going fast with a full load (think NT)

[BilboBoggles]

Isn't the lower pressure in the front deliberately set to reduce oversteer in severe situations? I remember reading that somewhere, the threah also stated that by running the tyres the same pressure all round the vehicle tends to oversteer in emergency situations and roll on it's back. Does that sound right? I know on mine that if the rear's get soft it tends to flick it's arse out around roundabouts.

(this came up in a thread discussing excuses insurance companies used to get out of accident claims, or other ways to end up in court over an accident)

[Benny_IIA]

Towing the Kamper on sealed roads I run my rears at 64psi and fronts at 40psi

Off road I drop them to 28psi when towing. Or less if conditions dictate.

Normal daily drive 32psi all round. 45psi rear if loaded up.

I'm still running the General Grabber TR's on the Boost alloys on the Puma.

My Tdi I run at 32psi normally - Cooper ST's (I think they left two letters out of the ST:angel:) on steel rims.

:eek:

[Allan]

Isn't the lower pressure in the front deliberately set to reduce oversteer in severe situations? I remember reading that somewhere, the threah also stated that by running the tyres the same pressure all round the vehicle tends to oversteer in emergency situations and roll on it's back. Does that sound right? I know on mine that if the rear's get soft it tends to flick it's arse out around roundabouts.

(this came up in a thread discussing excuses insurance companies used to get out of accident claims, or other ways to end up in court over an accident)
I dont think any Defender is up with a Nissan GTR at a round about drift demo. I am more likely to think the change in tyre pressure is load oriantated. No beem axle vehicle is ever going to handle and a Defender, At the end of the day is a tidy truck. Around town my son sets his tyre pressures on his BFG muds at 35 all round, the s1 Disco short wheel base doesnt like high pressure, in fact at 45-50 its un driveable on the road. My SVX with 8 inch rims and big mud rubber is happy at standard pressures. I think its all to do with your chassis/suspension setup

Allan

[Psimpson7]

Isn't the lower pressure in the front deliberately set to reduce oversteer in severe situations?

Wouldn't work IMO. Harder front tyres would increase the likelyhood of understeer, removing oversteer.

My 90 will drift quite amusingly on the brakes. It used to be hugely entertaining but the 2" lift has made it more rolly.

[Mellow Yellow]

Thanks for all the input. Much appreciated and very helpful.

What is clear :-
(a) everyone runs 32psi or above
(b) running the same pressure in all tyres is common but not universal
(c) increasing the rear tyre pressure when loaded is common but not universal (maybe some only carry light loads)
(d) the tyre pressures in my Land Rover manual (28F & 48R always) are not used by anyone.

In my original post I said; "I would have thought 32psi in the front whether laden or unladen. For the rear, 36psi unladen and 40psi laden."

As I typically don't exceed 100kph, I think that I'll only change tyre pressures based on whether I'm unladen or laden (i.e. heavily loaded & towing). [If I'm in the NT, this might change!]

The most suitable pressures for me now appear to lie in the range :-
Front 32psi to 36psi
Rear 36psi to 45psi.

So, I'm going to see if the following works for me :-

Unladen 32psi Front 38psi Rear
Laden 35psi Front 42psi Rear

Thanks for all your help.

[Blknight.aus]

thats how I did it for my tyres, experimentation. and you have to go through it all over again when you change or rotate the rubber.

[bosvit]

I have a 130 with BFG ATs (soon to be MTs :)), and I put 40 psi in front and rear, as they look flat when sitting there - unladen.

When doing bigger trips with alot of gear in the back, Ill put the back to 45psi, which improves the ride considerably. It doesnt feel like jelly, and they look just as they would when unladen.

Ill be interested to see what others use though, and how different these pressures are for 110 v 130.
Fraz
IMO that's because BFG ATs are a square tyre so they always look a little flat compared to a more standard shape like a Cooper etc.

If your BFG ATs do not have their outer and inner edges on the tarmac unladen you are over psi and will get too much centre wear (and not real good handling)

I've had BFG ATs on a lot of different utes for work, but went with Cooper ATs on my 130 due to cost and the fact that the squarer BFG ATs tend to follow the ruts on bitumen at speed more.

I run 38psi front (heavy bull bar, no winch) and 42ish psi rear unladen and 50ish psi laden or 55ish psi really laden eg 2.3 tonne boat, camper trailer on tray plus all our gear etc.

[bcj]

I run standard pressures in 110 c/chassis-though only round 40 in rear unloaded.I find this best as local council gone roundabout crazy-I think the larger footprint from front wheels and some sidewall flex help with cornering- I do run 7.50r16 tyres though.I live on gravel road and I like the softer ride at 28 as well.When driving in paddock I leave pressures as is-never get stuck.
Maybe 28 & 48 pressures best suit design parameters for defender-not actually best pressure for extended hwy use or larger/different tyre sizes.
Brett

[ramblingboy42]

I know I'm driving a D2 and not a fender but I set mine at 46 allround. So far 60k on Geolanders. as for understeer/oversteer, if you have lower front pressures, basically your car will understeer. D2 drivers can get great handling from their ace assisted vehicles just by increasing front tyre pressures.....or decrease rears. I personally believe most people dont drive their vehicles at optimum tyre pressures. Optimum does not mean maximum.