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Thread: Front vs Rear Tyre Pressures

  1. #1
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    Front vs Rear Tyre Pressures

    On a D2, the recommended front tyre pressure is in the order of 28 psi, but 38 on the rear. I have read a number of posts over the years that recommend upping the front pressures to roughly the same as the rears.

    I have to admit I have followed this advice and run both at the the high end of 38-40, given I usually carry a load of tools/other junk.

    The RRC has a similar 28/38 type recommended PSI.

    Would anyone like to comment on impacts of the front increase eg wear (tyres and also other components), handling etc.

    Cheers
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  2. #2
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    I have a defender and as a general rule I normally run the pressure front and rear when unloaded and 2psi more when loaded.

    An approach is to roll above a weight bridge and get you front and rear axle weights.

    The last time I weighed my defender...it was not loaded...given there is only 120kg difference I’m happy running he same pressures front and rear.


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  3. #3
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    I tried the 28-38 pressures when I first bought my D2a with the crappy 225/70/16 road tyres fitted and the front tyres looked to be under inflated and had a definite bulge/larger footprint even before I fitted the bullbar, winch and extra lighting.
    I now have 245/70/16 Yokohama's fitted and I run these at 38psi front and rear on the hard top now and down to 22psi front-25 psi rear on the beach and 28psi front-32psi rear for general off road work and the tyres look to have the same footprint at these pressures.
    I would imagine that having these tyres running at the recommended pressures when the CDL is engaged would cause problems.
    The tyres have now done about 50k and the wear is nice and even with no sign of over or under inflation at the pressures I have been running them at.
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  4. #4
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    I've run this set at 36 all round,, and with the edges on all 4 now getting thin it seems I should have been running more---
    The trade off is its not as comfortable as 28 but thats just 18's in general,,,
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  5. #5
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    The 28-38 recommended pressures are for European conditions I think, Here in Aus with an ambient temperature of 40C+ in many parts and God only knows how hot the road surface itself gets would have a dramatic effect on tyres running at 28psi at highway speeds one would think.
    You only get one shot at life, Aim well

    2004 D2 "S" V8 auto, with a few Mods gone
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  6. #6
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    I have always run mine at 28 front and 35 rear ( no load) and have absolutely normal wear on all tyres. I run 255 70 16 BFG ATKO and their load rating is so high that even at that the ride is quite harsh.

    Towing I increase the rears to 40.

    The reason is AFAIK that the front of a Disco or RRC is lighter than the rear particularly with a load in or towing with the towbar weight actually lightening the front. A bull bar and winch added may require a higher pressure but stock I have found 28 to be fine.

    Tyres are part of the damping of the suspension and higher front pressures amplify any potential problems like shimmy or impact damage like radiator failure.

    Regards Philip A

  7. #7
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    ive read somewhere the front was set lower to fix an understeer problem
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  8. #8
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    Quote Originally Posted by Eevo View Post
    ive read somewhere the front was set lower to fix an understeer problem
    I find it just wanders less/tracks straighter, overall less 'nervous' with close to the recommended pressures.

    I started running it the way I did the Deefer, even all around, but it was definitely nicer running lower in the front.

  9. #9
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    the pressures are like that to make the vehicle handle in a particular way.

    There was a point about weight, the D2 is 1.1t front, 1.2t rear
    Point about understeer, 28psi will induce understeer.

    In a nutshell, running pressures at the front at 28psi instroduces stability into the vehicle. It makes the front end tend to push when cornering hard and takes the sharpness out when turning in. I think it also removes some twitch from the trear. I really do think that 28psi is on the limits of the factory fitted tyre and it does create a notable amount of push even with alternative tyres.

    Running the tyre pressures higher in the rear gives them more traction and increases stability by controling lateral movement which is exacerbated by the longer overhang on the D2.

    So, at the recommended pressures you should be able to turn in and corner, and when traction starts to run out, it should just push but not twitch.

    If you check your pressure guide, it also tells you to go to maximum recommended (by LR) pressure when towing irrespective of the trailer. The D2's overhang makes it more susceptable to twitching and then hooking a trailer onto the back magnifies the twitching so by upping the rear pressures it helps to control the amount that it twitches by controlling the movement in the tyre, so it makes it a lot more stable and easier to drive when towing.
    Cheers
    Slunnie


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  10. #10
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    What about when using 260 70 16LT tyres? Does that change things?
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