How do I use tyre pressure to get better handling on different surfaces? - Page 2





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  1. #21
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    Default Re: How do I use tyre pressure to get better handling on different surfaces?

    As said:- First tell us how long is a piece of string.

    The problem with tyre pressures is, every thing changes constantly. The beach today 1.8 is ok, tomorrow on the same beach 1.2 is too hard......

    Weather, temp of road, temp of tyre, weight of vehicle and load, altitude, type of sand, type of gravel, speed, size and type of tyres, type of 4x4 and driver, etc, etc. AND TYPE OF DRIVING STYLE or mood.

    There is no such thing as the perfect tyre pressure for a road trip, unless you can guarantee no changes. short trips yes. Or doing a 4x4 trail, you go to recommended pressures, and pump up when finished.

    It is impractical to stop and change your tyre pressure every time the conditions change.

    For example driving down to CT from Durban, using as many gravel roads and passes as possible. To stop each time to change tyre pressure, will drive you crazy.

    There are good guide lines, as already posted for different conditions.

    So you look at the extremes. Every one of us has tried (and still try) that quick short beach drive without dropping pressures. Most of the time it's a no go. At Haga Haga there is a short 150m beach drive, (momentum has to be slow as it is a swimming crowded beach) we all try get by without changing the pressures, most of the time it's ok, as it is close to water. But many get stuck.

    Basically unless it is one type of condition/surface i.e. sand, mud, rocks, etc. Most of long distance 4x4 driving is done with the incorrect pressure for the conditions. too hard or too soft.

    You need to find that magical pressure in between, one that suits you and your vehicle.

    My farm cruiser - muds: occasional tar road, mainly off road farm use. I keep below 1.0. If I go to town 75kms away I pump to 2.2 due to no power steering.
    My work cruiser- muds: slow - short tar driving (speed limit max 100). lots of gravel. I keep at 1.6.
    My V8 cruiser, all terrain. used for long distance holiday fun and towing. I keep between 1.8 and 2.2 depending what I am doing.

    Altitude has a huge affect. take a drive from the heat on the coast to the top of cold sani, pressure changes hugely. if I leave home, drive the gravel and tar roads from home to sani - with the altitude and cold my low pressure alarms come on and the tyres are far too soft for the twisty roads in Lesotho

    BASICLLY most of us run a bit too hard, find the middle ground that suits you and then adapt the driving style to suit the road conditions. Unless it is specialists driving conditions as above.
    Current off-road vehicles: *** Great family accommodation. See Facebook, Google maps and airbnb. Wild Wind Ranch/Mkulu Kei
    * 1975/8 SHREK Land-Cruiser FJ40 DIESEL P/U, BFG 31x10.5 muds. 2 x 1.6 ton tirfor winchs
    * 1994 Land-Cruiser J70 DIESEL P/U, my truck recovery vehicle. 15000 warn winch. And 3.5ton tirfor winch. Back full of appropriate sized recovery gear. BFG31x10.5 muds
    * 2014 Land-Cruiser LX V8 76 DIESEL STATION WAGON, BFG's 285 all terrain.
    * 1988 HILUX TOYOTA 4x4 D/C.
    SOLD 2020 Jan.
    * 2011 HILUX 4X4 P/U, BFG 31x10.5 all terrain
    * 1999 PAJERO 3.5 V6 Mitsubishi (sorry not a Toyota), BFG 31x10.5 all terrain
    * 2006 FORD ranger 2.5 diesel. 4x4, (what was I thinking, also not a Toyota!) I have a spare 5000 warn winch I might fit.
    * 2011 Isuzu bakkie 4x4
    * FIONA - Rhino Yamaha 660 4x4. Warn winch. Mud tyres
    * 4x4 trailer, 1987, BFG all terrain
    * GSA 1200 BMW ADVENTURE LC 2018, the closest motorbike to a land cruiser
    * A Massey Fergusson 375 tractor. Not BFG's and not a 4x4




  2. #22
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    Default Re: How do I use tyre pressure to get better handling on different surfaces?

    It probably goes without saying, but here goes. Higher pressure on tar should result in better fuel economy. Lower pressure on tar should provide better traction (ex. circuit racing).

    Now I have some questions.

    Is lower or higher pressure better for kerb / curb hopping (stone or cement)? I don't want to crack by allies (aluminium wheels).

    So, are you saying that one needs to add pressure when driving from CT to JHB and if so, what is the usual drop?
    Renault Duster 4WD Gen1: No Meow

  3. #23
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    Default Re: How do I use tyre pressure to get better handling on different surfaces?


  4. The Following 2 Users Say Thank You to erduplessis For This Useful Post:


  5. #24
    Join Date
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    Default Re: How do I use tyre pressure to get better handling on different surfaces?

    With my vehicles and trailer I do a simple test to see how my tyre footprint is after loading the vehicle or trailer. (more so for the trailer)

    On a hard dusty flat surface (concrete floor) wipe the tyres clean with a damp cloth and drive across the dusty floor, you will be amazed (especially with light trailers with big tyres) at how the centre of the tyre bulges and the mid to outside treads do not even come close to touching the ground.

    It gives a very good indication of the true tyre footprint.

    This also gives a good indication on where the tyre will wear.

    On light/smallish trailers and vehicles the bigger the tyre the lower the pressure can comfortably go. This makes a huge difference on the way the trailer travels and the flexible tyres take the shock on the bumpy roads, like a shock absorber, making off road towing a pleasure.

    Over inflated tyres bulge in the centre, for all vehicles.

    The manufactures pressure recommendations are there to protect the tyres. no the ride.

    HIGH SPEED TRAVELLING stick to manufactures recommendations. I am talking about comfort in the bush and holiday cruising slowish below speed limit speed. Far too many traps and bad drivers out there to travel the speeds we did in the past.

    Having pressure monitors (x6) it opens a whole new world to tyre pressure and how it is affected during travel. I have them fitted to my 4x4 trailer as well.
    Current off-road vehicles: *** Great family accommodation. See Facebook, Google maps and airbnb. Wild Wind Ranch/Mkulu Kei
    * 1975/8 SHREK Land-Cruiser FJ40 DIESEL P/U, BFG 31x10.5 muds. 2 x 1.6 ton tirfor winchs
    * 1994 Land-Cruiser J70 DIESEL P/U, my truck recovery vehicle. 15000 warn winch. And 3.5ton tirfor winch. Back full of appropriate sized recovery gear. BFG31x10.5 muds
    * 2014 Land-Cruiser LX V8 76 DIESEL STATION WAGON, BFG's 285 all terrain.
    * 1988 HILUX TOYOTA 4x4 D/C.
    SOLD 2020 Jan.
    * 2011 HILUX 4X4 P/U, BFG 31x10.5 all terrain
    * 1999 PAJERO 3.5 V6 Mitsubishi (sorry not a Toyota), BFG 31x10.5 all terrain
    * 2006 FORD ranger 2.5 diesel. 4x4, (what was I thinking, also not a Toyota!) I have a spare 5000 warn winch I might fit.
    * 2011 Isuzu bakkie 4x4
    * FIONA - Rhino Yamaha 660 4x4. Warn winch. Mud tyres
    * 4x4 trailer, 1987, BFG all terrain
    * GSA 1200 BMW ADVENTURE LC 2018, the closest motorbike to a land cruiser
    * A Massey Fergusson 375 tractor. Not BFG's and not a 4x4




  6. #25
    Join Date
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    Default Re: How do I use tyre pressure to get better handling on different surfaces?

    Here's a rough guide that you can use on ANY vehicle, carrying any load. I say load, because that seriously affects what pressure you run.

    Measure the distance between the bottom of your rim and the (tar) road when unladen and inflated for daily tar running.......let's say that's 10cm

    Before deflating, get your vehicle laden for the trip.

    For dirt road travel deflate to 95% (9.5cm)
    For any offroading, 90% (9.0cm)
    For LOOSE sand driving 80-85% (8-8.5cm)

    If you do this often enough, you take out the valve, deflate until it looks right, put the valve back and off you go in under 5 minutes. Yes, with enough practice it can be done by eye.

    When you go below 90%, avoid high speed sharp turns. You SHALL take the tyre off the rim.
    Sakkie Coetzee

    Some people say I have a "short temper"....I see it as swift and assertive reaction to Bull!

  7. #26
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    Default Re: How do I use tyre pressure to get better handling on different surfaces?

    ....and if you cover long distances on hot sand, check again after about half an hour. The pressure would have increased quite a bit.
    Sakkie Coetzee

    Some people say I have a "short temper"....I see it as swift and assertive reaction to Bull!

  8. #27
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    Default Re: How do I use tyre pressure to get better handling on different surfaces?

    Our first venture into the SUV lifestyle was with a gen1 CRV, and we still harbour fond memories of back then On standard size tires I went down to 1.8 to soften the drive on gravel, and 1.6 on bad corrugations. These pressures I still run today on all my vehicles as a rule of thumb, and it works a treat. Sand I would do 0.8 rear, and 1bar front to both ensure slippage which engage the 4x4 system, and not have dreaded de-beads. Those worked well for me, but ultimately you will need some testing of your own to find what works nicely for you on the day as heat, load, gravel type, speed, etc. all plays a small part to give you the correct amount of confidence and comfort.

    PS I stuck 215x75 BFGs on it months before selling it, and it made everything worse. Yes, clearance and gravel grip improved though, but it was never a true 4x4 to start off with, so a wasted exercise Just don't do it, even though it looks great...

    youtube clips

    Gen 2 2.8TDi, running with a Lexus heart since 290000kms
    - developed a drinking problem since - V8 inception 2014/03/28
    - looking up after some driver rehabilitation and fine tuning (5.5-8.7km/l) 2015/08/14
    - keep the wheels on the ground at all times - 2014/12/04
    - body maintenance completed -
    2015/02/19
    ------------------------------------------------------------------------------

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