Trek Comment: Simpson Desert French Line

Correct, it might be remote from shops and garages, but certainly not remote from people.

Keep your weight to a minimum ..weight is a killer.

"Speed is not the answer, just slow and easy, and you will be fine."

Exactly....

People get the word MOMENTUM horribly confused with SPEED.

Speed will simply cause you to get a "Power Bounce" up which will churn up the tracks.

Tyre pressure, correct gear and momentum will get you up and over (almost) every time.

Cheers

Anthony

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Hi Anthony,

I even tire of the frequent expression of "MOMENTUM" which, in physics, refers to the quantity of a moving body defined by the product of mass and velocity.
So there again is the 'elephant-in-the-room'...... velocity. We are stuck with the "mass" from when we load up!

Recommending "momentum" is always interpreted as "speed".

Momentum also appears as energy imparted to a bullet as it leaves the barrel which must then carry it all the way to the target. However, a vehicle climbing a dune typically consumes much of the initial momentum before reaching the top of a difficult dune and then relies upon wheel torque alone to proceed at a constant rate. That the vehicle is capable of achieving this procession is demonstration of its ability to do so from the very start of the climb, so a high approach speed is needless. It is 'using a sledgehammer to crack a nut'.

Striving to gain maximum momentum invariably results in reaching a speed greater than required. It is only necessary to select the correct gear (and thus revs) to enable the vehicle to climb the grade. Much more comfortable and better for the track...... but not nearly as gung-ho. I gave up throwing my vehicle at a dune years ago and enjoy a more comfortable ascent.

As demonstration of the above, observe vehicles climbing Big Red. No vehicle gets far up before resorting to grinding up on power with all initial momentum extinguished. If the vehicle can transit the second half using power alone it may as well have done so through the first half.

The situation where momentum is vital is where the vehicle is incapable of climbing a steep slope by power alone and the climb is short enough for momentum to contribute all the way. But that is not the tough sand dunes.

I agree with your... "Tyre pressure and correct gear".... but believe the only speed necessary is to reach the correct point in the power curve before the climb. And having to change gears under threat is not good. I presume automatic transmissions should look after you nicely, but I wouldn't know about that.

Whew!

" that tyre pressures will be the secret to an easy drive, go high and will will have a trip from hell."
Yep, but then comes a caution to avoid overheating your tyres. Do that and you can destroy them all in a very short time.
Overheating is a direct result of gong too fast for the load/pressure, so keep a good watch on tyre temperatures.
Low pressures and low speeds and it will be easy.
Cheers,
Peter
OKA196 motorhome

It pays to remember at all times, that with any decrease in recommended tyre pressure, comes a resultant decrease in the load-carrying capacity of a tyre.

Conversely, an increase in tyre pressure means an increase in load carrying capacity - up to the tyres limit.

But the over-riding factor is exactly what Peter says - tyre operating temperature.
A good rule of thumb is, feel the tyre sidewall with your hand.

If it's comfortably warm to the touch, that's a good temperature limit.

If the rubber is too hot to keep your hand there for any more than a couple of seconds, the tyre is too hot, and you're risking carcass separation - whereby the natural rubber/styrene-butadiene mix that the tyre is made from, starts to "unvulcanise" from the polyester, rayon, aramid, and steel tyre cords, and the steel bead.

Carcass separation is identifiable by bulges appearing in the tread or tyre wall, as the air leaks into the space created by the separation of the rubber and the cords.

If you want to be really technical, take along an infrared heat gun and utilise it (as per manufacturers instructions) to get definitive tyre temperature readings.

Tyre rubber is capable of working satisfactorily at rubber temperatures of 225 deg F (107 deg C), and up to 250 deg F (121 deg C) for short periods.

However - be aware that rubber is a very poor heat conductor, and the outside of the tyre sidewall or tread is usually quite a bit lower temperature than the inside of the tyre.
The main heat buildup area is in the sidewalls, as the sidewalls generally flex a lot more than the tread.

Cheers, Ron.

Hi Guys,

Perhaps a better word is Traction. The moment you get wheel spin, you are losing traction.

Macca.

Allan, you've broken my head...

...time for a Bex and a good lie down LOL

Cheers

Anthony

"As demonstration of the above, observe vehicles climbing Big Red. No vehicle gets far up before resorting to grinding up on power with all initial momentum extinguished. If the vehicle can transit the second half using power alone it may as well have done so through the first half. "
Climbing Big Red from the west.
No screaming engines and no spinning wheels.
https://youtu.be/T7y61s_2vP0
Cheers,
Peter
OKA196 motorhome

The Perp ....being a self proclaimed nerd will be ready to take on Mount Everest after reading all that jargon LOL :)))

Like I said somewhere... go and enjoy.....plenty of others more than happy to help you ...

"1 OKA with a broken axle, who probably had the best simo experience, sitting atop a huge dune camped out."
Yes, we had a great time camped there for 8 days until the new axle arrived in Birdsville and was delivered by friends.

Cheers,
Peter
OKA196 motorhome

And a fly net:-)

... And Japanese "Safety Boots"

Cheers

Anthony

The flies were biblical just after Easter. Don't go without a fly net for your head.