100 series performance in soft sand (1 Viewer)

[divemedic]

Oh, and for anyone who thinks @divemedic is providing his own mathematical arguments, he literally is directly copying and pasting from "Outback Joe's" website while criticizing "Chaz at jeep parts r us."

Ridiculous.

Why Wide Tyres Don’t Help In Sand

Why You Shouldn’t Support Mandatory Vaccinations Last updated 25/08/2020 Click here for an article on how to drive in sand On the surface it seems like a reasonable assumption that wide tyres or &…

outbackjoe.com

I did, as people are more likely to read the post vs follow a link.

I also changed metre to meter, and removed hyperlinks.

I did this for readability not to take credit. I do concede this to be plagiarism, however that is not the intent.

 

[nukegoat]

I'm done here folks! Let the reader decide!

Have fun, outback joe

 

[flintknapper]

Another big issue, though, is that there is sand and then there is sand!

Now, from my limited experience, fine powder sand inland can be a different beast altogether.

^^^^

You got that right. In Deep East Texas we have areas of 'Sugar Sand' and it NOTHING like the sand you find at your average beach or sand dunes. When 'dry' it is horrible to try to get across.

If you plan to traverse Sugar Sand (my best advice is just to stay off of it) you'd better have as much flotation as possible, keep your speed up, make wide sweeping turns and keep your phone charged...because chances are excellent you'll be calling someone to help extract you at some point.

 

[WarDamnEagle]

Tall and skinny in the Middle East....at least with Land Cruiser pickups. Obviously air down and, yes a longer contact patch is better than a wider contact patch given equal square inches of contact. The longer contact patch digs in less. I think it’s as simple as that. Neither tire, aired down or not, will sink unless it’s moving.

Take a 6” long 2x4, lay it on flat sand and while applying the same pressure pull it backwards a few inches. Do this experiment with the 2x4 lengthwise and sideways and see which one piles up more sand.

 

[nukegoat]

Tall and skinny in the Middle East....at least with Land Cruiser pickups. Obviously air down and, yes a longer contact patch is better than a wider contact patch given equal square inches of contact. The longer contact patch digs in less. I think it’s as simple as that. Neither tire, aired down or not, will sink unless it’s moving.

Take a 6” long 2x4, lay it on flat sand and while applying the same pressure pull it backwards a few inches. Do this experiment with the 2x4 lengthwise and sideways and see which one piles up more sand.

Well, when I drive, my tires are rolling, not skidding. This experiment is hilarious

And you don't need the same number of square inches of contact patch. A wide tire gives you both a long AND wide contact patch. Durp!

How about going to the sand and using the skinniest tires you can find versus a fat ol 'flotation' tire?

 

[flintknapper]

We’re all still waiting for something with substance.

Here's some substance:

Not all things in the REAL world can be explained mathematically, nor do they necessarily adhere to concepts or theorems.

Some of what you've stated/cited is true, other parts of it ignore many variables. To your credit... you alluded to some of the 'faults' present in your proposal.

As for 'healthy debate'....I doubt that is what you are looking for. More likely an opportunity for another academic to show us how smart he is.

Maybe, you'll get some 'takers'...we'll see.

My advice to folks: Spend your time on something more useful.

 

[nukegoat]

^^^^

You got that right. In Deep East Texas we have areas of 'Sugar Sand' and it NOTHING like the sand you find at your average beach or sand dunes. When 'dry' it is horrible to try to get across.

If you plan to traverse Sugar Sand (my best advice is just to stay off of it) you'd better have as much flotation as possible, keep your speed up, make wide sweeping turns and keep your phone charged...because chances are excellent you'll be calling someone to help extract you at some point.

You probably need to run skinnier tires

 

[WarDamnEagle]

Well, when I drive, my tires are rolling, not skidding. This experiment is hilarious

And you don't need the same number of square inches of contact patch. A wide tire gives you both a long AND wide contact patch. Durp!

How about going to the sand and using the skinniest tires you can find versus a fat ol 'flotation' tire?

Actually if your tire didn’t “skid”, even on asphalt, your car would never move forward. That is an indisputable law of physics. (Second edit: I should have said fact based on the laws of physics. My mistake.)

A wider tire will not give you wider and longer at the same pressure assuming the same tire flex. I don’t think you understand. For any given pressure a tire will have a fixed contact area. If it’s wider it can’t be as long. That assumes similar tire construction (rigidity) and the same pressure.

Edit: skinny is only better to a point. Once the tire cannot extend itself because it’s flat against the rim then you are outside of this discussion. So, no, a bicycle tire on an FZJ75 isn’t going to be better.

 

[Lumpskie]

W A wide tire gives you both a long AND wide contact patch.

I have no idea why I'm on the 100 series forum... but I've tried to say this same thing on deaf ears myself. My experience has proven that more contact patch is better. I know it defies the simple formula for friction but, in my mind, the limit of traction on a tire in soft stuff isn't the friction surface. It's more like the shear of the surface against itself... if that makes sense. In that way, to more interface you have between the tire and the surface, the more propulsion you can make.

I doubt this makes any sense, outside of my mind. I'll go back to my hole now.

 

[nitteo]

it works for us 100s down here in sandy florida, powder sand (ground up limestone), shelly coarse beach sand, wider more contact is best. at tires do better than mts also.

 

[nukegoat]

Actually if your tire didn’t “skid”, even on asphalt, your car would never move forward. That is an indisputable law of physics. (Second edit: I should have said fact based on the laws of physics. My mistake.)

A wider tire will not give you wider and longer at the same pressure assuming the same tire flex. I don’t think you understand. For any given pressure a tire will have a fixed contact area. If it’s wider it can’t be as long. That assumes similar tire construction (rigidity) and the same pressure.

no, but for the 11ty billionth time in this thread, i'll say it again - you don't have to run the same pressure in a wider tire. You can go lower!

 

[WarDamnEagle]

no, but for the 11ty billionth time in this thread, i'll say it again - you don't have to run the same pressure in a wider tire. You can go lower!

We generally air down here to 22 and if that doesn’t work 17, regardless of the tire. I do this on my 200 series and my FZJ75 pickup even though they have very different tires.

I have to admit it isn’t obvious to me why you can run wider tires at lower pressures? Would like to know though if you would care to explain. I’m by no means a tire or rim expert.

 

[divemedic]

Here's some substance:

Not all things in the REAL world can be explained mathematically, nor do they necessarily adhere to concepts or theorems.

Some of what you've stated/cited is true, other parts of it ignore many variables. To your credit... you alluded to some of the 'faults' present in your proposal.

As for 'healthy debate'....I doubt that is what you are looking for. More likely an opportunity for another academic to show us how smart he is.

Maybe, you'll get some 'takers'...we'll see.

My advice to folks: Spend you time on something more useful.

I have no idea why I'm on the 100 series forum... but I've tried to say this same thing on deaf ears myself. My experience has proven that more contact patch is better. I know it defies the simple formula for friction but, in my mind, the limit of traction on a tire in soft stuff isn't the friction surface. It's more like the shear of the surface against itself... if that makes sense. In that way, to more interface you have between the tire and the surface, the more propulsion you can make.

I doubt this makes any sense, outside of my mind. I'll go back to my hole now.

I understand what you are saying, and generally you are correct. However, in sand their is such a thing as too much. Exemplified by a well designed AT tire performing better than a MT.

 

[divemedic]

no, but for the 11ty billionth time in this thread, i'll say it again - you don't have to run the same pressure in a wider tire. You can go lower!

So a narrow tire cannot air down?

so I’m understanding; if I compare a tire sized 315/70r16 to a tire sized 255/85r16, I can air down further in the 315? Because it’s wider....

 

[nukegoat]

so I’m understanding; if I compare a tire sized 315/70r16 to a tire sized 255/85r16, I can air down further in the 315? Because it’s wider....

Yes

 

[divemedic]

Yes

care to elaborate?

 

[nukegoat]

We generally air down here to 22 and if that doesn’t work 17, regardless of the tire. I do this on my 200 series and my FZJ75 pickup even though they have very different tires.

I have to admit it isn’t obvious to me why you can run wider tires at lower pressures? Would like to know though if you would care to explain. I’m by no means a tire or rim expert.

Because for the very same reason the contact patch is larger - you have the force (weight of the vehicle) distributed over a larger surface area. You require less PSI to support it.

In terms of force, 20 psi over 20 square inches = 40 psi over 10 square inches.

 

[nukegoat]

Care to elaborate?

See above

 

[WarDamnEagle]

Because for the very same reason the contact patch is larger - you have the force (weight of the vehicle) distributed over a larger surface area. You require less PSI to support it.

In terms of force, 20 psi over 20 square inches = 40 psi over 10 square inches.

I’m sorry but it doesn’t work that way. Seriously

 

[Lumpskie]

I understand what you are saying, and generally you are correct. However, in sand their is such a thing as too much. Exemplified by a well designed AT tire performing better than a MT.

Not sure I follow... are you saying a bigger contact patch is worse? Are you making a statement about the biting edges of an AT?