Are original general grabber tires suitable for Simpson xing

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Originally Posted by Beckford

Another silly question. What pressure are people running for;

1. Dirt (fire trails)
2. Mud
3. Sand
4. Rocky river crossings

Thanks, Beckford.

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How heavy is your Rig?

A "set" pressure is not really possible.

As a guide though I run around 22psi on sand for a start point.

The rest I adjust to the weight and conditions..

I'll back tombie...

any numbers you get for the "correct" tyre pressure should be treated as a good starting point, based on a whole bunch of factorsyou need to change your tyre pressure, I know some places where you have to bag down as the temperature goes up then air up again at night.

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Originally Posted by rovercare

They'll be fine, unless its boggy, but usually the bypass will be good

I have no idea why people get stuck on dunes, I swear you have to be a little retarded, when you start bogging, dip the clutch, back down and go again, its far easier than having to snatch, I watched people do this getting stuck thing, stupid!, don't be scared to keep the rev's up, on the governor if you have too, this won't hurt your engine and will only make the largest dunes a doddle to cross, momentum is key

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I agree momentum is vital however some dunes, due to previous persons not having the correct tyre pressures, chew the summit of the dunes up and to try and use momentum on these results in you, your passengers, fridge, supplies and other gear bouncing to the point where you do damage to them and yourselves.

We had this problem on numerous occasions and you had to slow down or risk doing damage. When this occurred in some instances by the time you tried to stop, back up and have another go you were already bogged.

More the exception rather than the rule.

Thats what was happening when I went across,a tag along group was going the other way and they left the dune tops like the first day of the somme. Pat

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Originally Posted by Chenz

I agree momentum is vital however some dunes, due to previous persons not having the correct tyre pressures, chew the summit of the dunes up and to try and use momentum on these results in you, your passengers, fridge, supplies and other gear bouncing to the point where you do damage to them and yourselves.

We had this problem on numerous occasions and you had to slow down or risk doing damage. When this occurred in some instances by the time you tried to stop, back up and have another go you were already bogged.

More the exception rather than the rule.

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Dunno, when I went was driving my old boys Factory turbo troopy towing a kimberely camper east to west, only stuck once as there was a zillion people playing on the dunes as we left after the birdsville races and got cut off half way up, don't get me wrong a few times stuck, but dip the clutch in time and simply back down and go again

Tyres at 14psi front 18psi rear and 14psi in the trailer

Also lots of people refuse to lower their pressures less than 20-25psi, which also doesn't help

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Originally Posted by rovercare

They'll be fine, unless its boggy, but usually the bypass will be good

I have no idea why people get stuck on dunes, I swear you have to be a little retarded, when you start bogging, dip the clutch, back down and go again, its far easier than having to snatch, I watched people do this getting stuck thing, stupid!, don't be scared to keep the rev's up, on the governor if you have too, this won't hurt your engine and will only make the largest dunes a doddle to cross, momentum is key

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Momentum is not always suitable though, if the run up the dune is chopped up or across spinifex mounds. It's not always the face of the dune that's the problem, quite easy to get bogged on a wind blown lip off the back of the crest, and I would suggest too much momentum in that case is definitely not the best idea.

Overall though momentum will be what gets you through, but, not everyone will judge it perfectly everytime.

Martyn


Martyn

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Originally Posted by Bushie

Momentum is not always suitable though, if the run up the dune is chopped up or across spinifex mounds. It's not always the face of the dune that's the problem, quite easy to get bogged on a wind blown lip off the back of the crest, and I would suggest too much momentum in that case is definitely not the best idea.

Overall though momentum will be what gets you through, but, not everyone will judge it perfectly everytime.

Martyn


Martyn

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I'm not argueing the actually not making it up the dune, more the silliness in keeping the foot in until your stuck prior to backing down, sure you can't judge every dune correctly, but you can off the power and dip the clutch for a rerun, before chopping up the dune moreso having left big holes and being snatched out

Had no crests to drop off on as the are all on the east side which was the way of approach when i went as we went birdsville to dalhousie

A lot of talk here about momentum being THE way of tackling the sand ridges in the Simpson and although I agree with that I would like to offer the following for discussion.

While momentum is important, as 'Bushie' alluded to, more momentum than necessary can be more of a disadvantage than an advantage. So what do I mean by that? Well, in general, the ideal amount of momentum to clear an obstacle is the amount that enables you to just make it through/over the obstacle. This is often very difficult to judge but naturally improves with experience. If you are willing to tackle each obstacle slowly and with caution, if you don't make it the first time you can then assess where the shortcoming was (maybe a different line, different gear, different tyre pressure or maybe even a little more momentum) but by taking it easy the first time, you'll have far less likelyhood of breaking something and therefore a chance of a second go with that little bit of added experience.

One thing to remember is that if your wheels are spinning and throwing 'rooster tails' of sand (or whatever) out behind you then you have lost traction and are digging your way forward in ever diminishing amounts until you reach a point where you FTP. As soon as your wheel/s start to spin the natural reaction is to push your right foot through the floorboards when in fact, the way to regain traction is to ease off the go pedal. How much to ease off is where your experience comes in as you need just enough to stop the spinning while retaining sufficient gopedal to maintain your momentum.

And for those with TC, I have found that, by using the above method, I have never considered it necessary to disable the TC. Remember also that TC works by sensing a difference in revs between wheels and the way I've observed some people drive, with all wheels spinning madly, there is probably no difference in revs of the spinning wheels so therefore their TC is in effect inoperative under those circumstances.

Enough of a rant for now and probably also enough to generate some comment.

What rovercare said is true too,many people refuse to let their tyres down enough when driving on sand but that said they do drive vehicles that are alot heavier than ours. Pat

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Originally Posted by PAT303

What rovercare said is true too,many people refuse to let their tyres down enough when driving on sand but that said they do drive vehicles that are alot heavier than ours. Pat

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Not disputing Rovercares comments, but Chenz was talking about the Madigan Line and not the usual Simpson tracks. Some may argue, but they are a different kettle of fish.

When letting tyres down for sand driving, I usually start at 22 and so far, have not had to go lower.