Tyre footprints

Submitted: Sunday, Jun 03, 2007 at 12:55

ThreadID: 46211 Views:3503 Replies:6 FollowUps:6

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Willem

I haven't taken my MFR Super Traction tyres into sandy conditions yet and with a short desert trip coming up soon I thought that doing measurents might give me some idea of where I might be at.

Measurements are only approximate.

Unfortunately I don't have comparisons with my now buggered Cooper STT's which performed very well in sandy conditions. Maybe someone else has those measurements to share.

Front wheel Nissan GQ

MRF Super Traction 12 ply rating 750x16 tubed

Tread width 180mm

Sidewall bulge @ 40psi 40mm
Tread footprint @ 40psi 285mm
Soft sand footprint 285x 220mm

Sidewall bulge @ 35psi 45mm
Tread footprint @ 35psi 290mm
Soft sand footprint 290x225mm

Sidewall bulge @ 30psi 50mm
Tread footprint @ 30psi 295mm
Soft sand footprint 295x230mm

Sidewall bulge @ 25psi 55mm
Tread footprint @ 25psi 300mm
Soft sand footprint 300x235mm

Sidewall bulge @ 20psi 60mm
Tread footprint @ 20psi 310mm
Soft sand footprint 310x240mm

Sidewall bulge @ 15psi 70mm
Tread footprint @ 15psi 320mm
Soft sand footprint 320x250mm

Sidewall bulge @ 10psi 80mm
Tread footprint @ 10psi 330mm
Soft sand footprint 330x260mm

Cheers

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Reply By: warfer69 - Sunday, Jun 03, 2007 at 13:13

Reply By: Member - Doug T (W.A) - Sunday, Jun 03, 2007 at 13:21

Reply By: age - Sunday, Jun 03, 2007 at 15:34

Reply By: Member - Phil G (SA) - Sunday, Jun 03, 2007 at 19:22

Sunday, Jun 03, 2007 at 19:22

OK I'll bite...................
I used two pieces of 9mm ply in front of and behind the tyre to measure footprint length. I didn't measure width because my sidewall doesn't touch the ground :-) But the tread is 220mm across - don't know how you got your 750's to be so wide???

Goodyear Silent Armour 10ply 265/75R16 Load Index 123 (same diameter as your 750R16)

43psi 260mm
35psi 280mm
25psi 300mm
20psi 320mm
15psi 360mm
10psi 390mm
7psi 430mm
5psi 460mm

My conclusion is that you won't be pulling the trailer over the dunes unless you go to 5 psi :-))

Cheers
Phil

AnswerID: 244456

Follow Up By: Member - Phil G (SA) - Sunday, Jun 03, 2007 at 19:28

Sunday, Jun 03, 2007 at 19:28

"don't know how you got your 750's to be so wide???"

Whoops missed the 180mm bit :-))

FollowupID: 505418

Follow Up By: Willem - Monday, Jun 04, 2007 at 05:56

Monday, Jun 04, 2007 at 05:56

Thanks for biting Phil :-)

With the sidewall I took into account that the tread would sink into the sand and the sidewall would stabilise against the side of the cut made by the tread.

Yes, it is going to be interesting to say the least. The Coopers at 15psi handled well in the sand. Maybe that was a tad low and 18 would probably have been OK as well.

An old desert traveller(name unknown) told me once in Birdsville that when he ran his tyres in sand, he ran them at 14psi on the Troopy and at 10psi on the trailer and that this was good enough for the Simpson. He was running radials on splits. Now I am not quite sure whether he did any offtrack stuff. Beadell Tours run MRF Supermilers on their Landy out in the desert and offtrack and it works well for them but they don't tow a trailer.

I will start the experiment on Little Red and see where it gets me....LOL

10psi on a MRF 14ply rating M77, on the trailer, doesnt even look bulged.

Cheers

FollowupID: 505555

Follow Up By: Member - Phil G (SA) - Monday, Jun 04, 2007 at 11:15

Monday, Jun 04, 2007 at 11:15

Willem,
You and your fuel trailer remind me of the Leyland Brothers in 1966. They wrote a book "Where Dead Men Lie" which described their across australia adventure. They had 2 LandRovers, one towing an oversized trailer. Their technique described in the book, was to send the lightweight SWB vehicle with fat tyres over the dune with a long rope and pull the second vehicle and trailer by driving the first vehicle down the dune. They reckon it worked. But after they broke a couple of diffs near Andado, I'm a bit surprised no other damage was reported until they got towards Birdsville. There are rumours around that they may have utilised the newly built French Line but they deny this.
Theres an interesting bit of discussion on the French Line Site by the workers who were out there.

FollowupID: 505603

Follow Up By: Willem - Monday, Jun 04, 2007 at 16:28

Monday, Jun 04, 2007 at 16:28

Well Phil, Its like this....lol

I would havee loved to buy a ute. But the only ute in which I could fit comfortably sort of, is a new Nissan(or slightly second hand). Both beyond my financial reach.So I ended up with the GQ.

I have seen too many vehicles break from being overloaded. So, against my better thoughts, I went out and bought a trailer. The trailer weighs in at 800kg all up when leaving base. After first fuel changeover it gets lighter all the time.

Last year I dragged the trailer to the Geo Centre of the Simpson, out and beyond the Cleland Hills, along the AB, DCarnegie, Eagle Hwy and then 200km Offtrack to the Calvert Ranges. I broke a Ubolt later in the year on a track at Warraweena. The trailer performed well.

So now I am looking at doing some stuff in the Simpson again. If the easy stuff proves too difficult with the trailer then I will do the offtrack stuff another time.

I am very careful when travelling offtrack and look where I out the wheels so that the ride may be a lot smoother.

Cheers

FollowupID: 505664