Simpson

Submitted: Thursday, Jan 05, 2017 at 15:21
ThreadID: 134052 Views:2831 Replies:8 FollowUps:11
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Hello all..
We are considering doing the Simpson in our Silverado. Width should not be a problem @ 2030 wide it not much wider than 200 series. Wondering about getting hung up in the middle with such a long wheelbase and a huge diff pumpkin ??.. Haven't started looking at which track would be the most suitable. If Anyone who has done it in the Silverado could tell me their experiences that would be good..
Regards Danny
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Reply By: Member - KeithB - Thursday, Jan 05, 2017 at 22:19

Thursday, Jan 05, 2017 at 22:19
We did the Simpson, west to east on the French Line, a year or two ago at the beginning of the season in a locked and lifted 200 series with 33s towing a 1200kg trailer. The track was in good nick and we took it slowly and didn't lose traction once. It may have been a different matter at the end of the season with dry weather and a cut up track.
Just looking online, the SWB Silverado has a wheelbase just 2 inches longer than the 200 series and the LWB is 21 inches longer. Dropping tyre pressures to 20 psi or lower for the sand will reduce ground clearance and make matters worse.
More experienced travelers may have better advice, but the WWA LIne and Rig Road may be the best choice.
Take all the revovery gear you might need, plus spares, a sat phone and plenty of freeboard on your credit card in case you need to be towed out, which I doubt would happen.
Have a wonderful trip and make sure you have enough time to take it all in.
AnswerID: 607251

Follow Up By: gbc - Friday, Jan 06, 2017 at 11:23

Friday, Jan 06, 2017 at 11:23
Dropping tyre pressures will improve the situation no matter what the wheelbase/rampover relationship is. It sounds counterintuitive but it works because overinflated tyres bite rather than float so you lose any sidewall height advantage before you start by not airing down. Years of towing road based boat trailers with zero clearance up beaches has proven this - tyres down no matter what, and if you get stuck you let them down more - rampover is a luxury which is further down the list unfortunately.
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Follow Up By: Member - Stephen L (Clare SA) - Friday, Jan 06, 2017 at 11:36

Friday, Jan 06, 2017 at 11:36
Hi Keith

First of all without being negative, but your comments:-

"Dropping tyre pressures to 20 psi or lower for the sand will reduce ground clearance and make matters worse."

This is the most misleading information that you can give to any vehicle in soft sand. It is drivers that do not drop tyre pressures that are true vandals of the desert and cut the hell out of the tracks and make it harder for the following vehicles.

Just wondering when you drove the Simpson Tracks, what tyre pressures were you running and at what speeds were you travelling. My advise for any new drive to the Simpson is to start at 14psi and you will be able to crawl your way slowly over the dunes and not cut the track up, and clearance is never an issue.

Cheers


Stephen
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Follow Up By: Member - KeithB - Friday, Jan 06, 2017 at 13:38

Friday, Jan 06, 2017 at 13:38
Stephen,

I think you have misinterpreted what I said. Dropping tyre pressures for sandy conditions is vital, but it does also reduce ground clearance. This is an objective fact. To suggest high pressures to maintain ground clearance is madness.

We started from Mt Dare with 13-16 cold and 13 on the trailer, which went to 16-19 hot and had no problems. I monitored tyre temps with a digital meter whenever we stopped - more out of curiosity than anything else - and they stayed at about 55 degrees.

We went nice and slow and saw no need to rush dunes at any time. The only runup was to get the trailer happily up the Chicken Track at Big Red, with all diffs locked. Did 26 l/100 for the crossing with 3.4 tonnes vehicle and 1200kg trailer. We did not lose traction and did not damage the track, which I mentioned was in good nick earlier in the season.

A lot of people suggest tyre pressures without mention of whether they are hot or cold pressures. Dave at Mount Dare once told me that a lot of people pull up for the night after failing to crest a dune and then find the same dune easy going in the morning, after the tyres had cooled down.

I do wonder whether a 121 inch wheelbase and low ground clearance might be an issue when the dunes switch direction at the crest. Mandatory reduction of tyre pressures for sand will reduce ground clearance.
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Follow Up By: Michael H9 - Friday, Jan 06, 2017 at 13:47

Friday, Jan 06, 2017 at 13:47
I think what Stephen is saying is that reducing tyre pressure on a firm surface will certainly reduce ground clearance, but reducing pressure on sand will keep you on top longer. Any increase in clearance by higher pressures on sand is eaten by the tyres sinking further into the sand.
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Follow Up By: Member - KeithB - Friday, Jan 06, 2017 at 14:46

Friday, Jan 06, 2017 at 14:46
Good point
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Follow Up By: Member - Stephen L (Clare SA) - Friday, Jan 06, 2017 at 16:24

Friday, Jan 06, 2017 at 16:24
Hi Keith

No worries and yes I did misinterpret your pressures. You did the correct thing with pressures, but unfortunately not all people do the right thing.

On one of our solo Simpson trips, we could hear a convoy of Tag a long vehicles in front of us having all sorts of trouble getting over the dunes as we were heading west after Big Red. Some of the group were having more than 4 attempts to get over the dunes, on what I could only says as easy dunes to cross. The track was a real mess to so the least and it turned out that there were 9 vehicles in the group.

We held our comments to ourselves thinking that they must be new to sand driving and not knowing their ability, until we heard the guy in charge of the group ask a few of them what tyre pressures they were at........45psi was the reply over the radio, then the leader said try dropping them by 10psi to 35 psi.

I will not tell you what I said to Fiona about these Cowboys and the so call leader. I jumped onto the radio and made contact with one guy that was last and having all sorts of trouble, asked him to stop and I will be there shortly.

We caught up with him in around 15 minutes and he was in all sorts of a pickle, thinking he was going to be left behind and he thought that there was no way he was going to be able to cross the desert at his current rate. Having a chat one on one, we found out the group was 9 vehicles and they had all paid over $2500 just be be lead across the Simpson. When I asked why was he running far too high pressures, the reply was that was what the leader had told them to run, with horror stories of running lower pressures. To make him feel better, I told him to trust must and take no notice of the leader. We dropped his pressures to 18psi hot, knowing they would be around the correct pressure when cold. I told him not to use speed, but just take his time. Then for the dune that had halted him, he went up with easy. He sat at the top and the smile on his face told a thousand word, and I told him I would follow him until he caught up the to the rest of the group that left him alone in the desert.

The rest of the group were having lunch at the Eyre Creek Crossing, where he again made contact with his group. I wished him all the best, and asked him to tell the others in the group to drop their tyres down to the same as I had put his.

That was the last we saw or heard of the group until a few days later at Dalhousie. I greeted the chat that was having all the trouble and asked how did the rest of the group go? He said that only 2 other vehicles dropped their pressures down and they were the only three vehicles that had no more trouble getting over the dunes. He did say that when he asked the leader about the high tyre pressures that they were running, the so called leader called me a smart arse and a few other choice words and who was I to question his experience.

You can now see why I have a dislike for drivers with high tyre pressures in the desert and people who rip people off in the so called Tag a Long groups and do not do the right thing in helping them drive responsibly in the deserts.



Cheers



Stephen
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Follow Up By: gbc - Friday, Jan 06, 2017 at 16:39

Friday, Jan 06, 2017 at 16:39
Couldn't agree more. There isn't an argument about what is right, yet some still don't get it.
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Follow Up By: Member - KeithB - Friday, Jan 06, 2017 at 17:40

Friday, Jan 06, 2017 at 17:40
Someone should invent a hat with brains and hand them out for free.
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Reply By: Blown4by - Friday, Jan 06, 2017 at 00:23

Friday, Jan 06, 2017 at 00:23
If your Silverado is similar to one owned by a friend of mine, the auto trans cooler is mounted just in front of the rear axle and is very susceptible to stone damage from the front wheels. It also hung down fairly low and the mounting brackets being of insufficient strength failed. If yours is the same I would consider at least guarding it whilst not restricting air flow or better still, re-positioning it. He has also found that whilst these vehicles have a high GVM/GCM they are made primarily for use on sealed roads in USA as are many of this type of imported vehicle. Being of fairly light construction he found on rough roads/corrugations, etc. cracking on brackets securing the front bumper and other similar fabricated items was problematical. Not knocking the vehicle, just relaying his experiences.
AnswerID: 607256

Reply By: Les - PK Ranger - Friday, Jan 06, 2017 at 10:48

Friday, Jan 06, 2017 at 10:48
If yours is a SWB as mentioned it should be ok.
If LWB you could have some issues on all 3 main lines.

Many dunes have the easy way over, and a harder line, usually over the more peaked dune tops, which could be a ramp over issue.
Take the easy gradual line, usually gradually countouring up the dune.

The other thing with longer wheel base vehicles, dunes on all 3 lines do have some twists and turns plus 'holes' on top that a LWB could have trouble with.
Rig Rd has quite a few of these, though last 2 day crossing (it was hot) it was a very easy drive in general for normal size vehicles.

Personally, in the future I'm now going to avoid French Line after the last 2 crossings, it is just an undulating mess from near Knolls almost to Rig junction.
Much prefer WAA line, which could be your best choice.

Not sure of your intended direction of travel, but West to East is likely easier for you with the gradual incline side of the dunes predominant, and I would go Rig Rd - WAA - Knolls, then the usual French line to Poeppel, and QAA to Birdsville.
AnswerID: 607269

Reply By: Member - Stephen L (Clare SA) - Friday, Jan 06, 2017 at 11:26

Friday, Jan 06, 2017 at 11:26
Hi Danny

The biggest thing that many new drivers in the Simpson under estimate it tyre pressures, they stay far too high, and in return cut the hell out of the tracks.

You will only be travelling slow, between 20 - 40 kilometres per hour. You are not going break neck speeds to roll your tyres off of a rim.

The lower the tyre pressure, the greater the footprint while in the soft sand and it will look after the tracks, make your drive so much easier and make getting bogged that little bit harder.

Seeing you are a first time Simpson driver, start at 14 psi and you will not have any problems, and the 20psi stated above is too high.

Have a great drive.



Cheers



Stephen

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Follow Up By: Les - PK Ranger - Friday, Jan 06, 2017 at 11:53

Friday, Jan 06, 2017 at 11:53
Good advice on tyre pressures Stephen, THE most important thing in taking pressure off your vehicle / making best progress, after actually using 4WD !! (Some seem to take pride in saying "I did it all in 2WD !!)

But I'd definitely advise do it progressively if travelling west to east (supposedly easier direction) as the dunes in the west are quite significantly smaller, and as you travel east they get larger right through to QAA, which I'm sure most would agree has most of the larger dunes.

It will depend on tyres too, brand, size, type, sidewall stiffness, as to what best pressures are.
The best tyres for this travel have high side walls, stiff AT LT construction, light tread pattern, and don't bag sideways too much, but more lengthwise for longer footprint.

This is all based on the desert generally being dry, sand soft . . .

I'd say with full load in the west region, you could easily start at 22 / 24 or so at Dalhousie, get out to Purni go 18, hit Rig / WAA then after those couple of easy days then go maybe 16 minimum, if needed considering the weight of this beast he's driving.

As he heads more east, and gets to the larger dunes, then the vehicle weight with less fuel, water, beer, food, etc, will allow lower pressures to tackle these dunes and of course get over Big Red.

If he's going east to west, he will have full loads, biggest dunes, most dug up tracks, afternoon sand will be difficult on those steeper sides, especially if dry.
Tyre pressures slightly higher will give the similar footprint as a few psi higher under full load.

I'd much prefer (if in the OPs case) going west to east so it sort of balances load weights / terrain difficulty / tyre pressures very nicely.
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Follow Up By: Member - Stephen L (Clare SA) - Friday, Jan 06, 2017 at 12:53

Friday, Jan 06, 2017 at 12:53
Hi Les

Travelling from the west is easier, a sit is a gentle approach to the dunes.

On the other hand we like the extra fun and prefer travelling from the east. The only problem with this is there is no Birdsville at the other end.

As all experienced travellers know, tyre pressures are the key issue for an enjoyable drive across the Simpson.



Cheers



Stephen
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Follow Up By: Les - PK Ranger - Friday, Jan 06, 2017 at 13:08

Friday, Jan 06, 2017 at 13:08
Yes, I'm the same now after going both ways a few times either way has it's pros and cons.

I feel the longer west dune faces, while better for lower slope angle, do get rutted very badly as it's the more popular direction, and many don't give up soon enough and have another go, they sit there bogging in.
The east dune faces though generally sharper, you can usually go up them with a little more momentum no worries.
That sort of balances out difficulty.

You just need to be careful taking on Big Red and the bigger eastern dunes too much with full fuel / water / food etc loads.

The best thing about finishing in the west ? A Dalhousie dip :)
The other way, the pub, and June I had a washdown at the town car wash too !!! Very nice :D :D

I'm now concentrating more on north Simpson trips, regular SA crossings seem to get just too easy once you get a little used to the place . . . even Madigan line seems cushy :D !!
I can see me going through again some trips in the future, it's just a peaceful place to take 4 days or so to camp out there . . . maybe some zig zag of the N-S tracks as well, or maybe accessing north Simpson via other tracks into the NT, though need a DPP then for only a little access use.

Happy travels.
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Reply By: Danny C3 - Friday, Jan 06, 2017 at 13:59

Friday, Jan 06, 2017 at 13:59
Thanks everyone for the replies..
Still thinking ground clearance may be the biggest issue as it is a LWB.. pretty well up with tyre pressure etc as we have done the canning,connie sue,sandy blight etc. but not in the chev.. it has a rear locker so that is a help but don't want to get hung up on the tops of dunes..
Cheers Danny
AnswerID: 607282

Reply By: terryt - Friday, Jan 06, 2017 at 16:33

Friday, Jan 06, 2017 at 16:33
Danny, why don't you see if you can find some dune country a bit closer to you. That way you could have a play and sort things out before you end up stuck on a dune halfway across the Simpson.
Just a thought
Terry
AnswerID: 607291

Reply By: Member - McLaren3030 - Saturday, Jan 07, 2017 at 09:45

Saturday, Jan 07, 2017 at 09:45
Danny, we crossed the Simpson in 2015 and came across a GMC Suburban crossing East to West. He had diff locks so climbing the dunes did not seem to be a problem for him. He also went up & down Big Red with ease at Los speed. Not sure how he coped with ramp over, as we did not get a chance to speak to him for very long. Macca.
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Reply By: Been-Everywhereman - Sunday, Jan 08, 2017 at 08:59

Sunday, Jan 08, 2017 at 08:59
Hi. In 2011 we crossed The Simpson Desert with 7 cars in our group with one of them being a Silverado LWB with a huge 6. something litre v8 diesel automatic.
We left from Oodnadatta and finished at Jervois.
The tracks travelled were French Line then onto the Rig Road then left onto the WAA line all the way to the end and then up to Poeppel Cnr (spelling could be incorrect because it is too early to care). Then due north from there up the Hay River Track.
He (Noel) got stuck on dunes more than any other car due to his length but the hardest thing for him was he sometimes would belly out and had to dig to free himself where we could just back down again without shovel work.
The air intake was at the bottom of the engine area and I remember his engine warning light came on about half way along the WAA line which frightened him (and us) but it turned out to be a fuel delivery problem when he checked his code reader which lead him to check the air filter and it was absolutely full of sand because the air intake acted like a shovel every time he crested a dune it was literally shovelling sand into the air box. He probably emptied 3 coffee mugs of sand out and then the problem was solved.
After that he got stuck on dunes more because he was scared to attack them hard because he knew what was happening now with the air box. He had a lot of fun though but did say it was hard work at (60 years old) and his fuel consumption for the whole trip was 31 litres per 100kms keeping in mind the Hay River part of it was easy driving. Cheers.
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