Ground pressure

[CTyler]

</font><font color="blue" class="small">( Is it one of those neighborhoods where you have to mow your lawn in a certain way or the 'owner's association' won't invite you to the Saturday night social ??
)</font>

Don't forget the roller to make it lay the pattern correctly.

 

[Renze]

Yes, many people with little knowledge have different wishes...

At the park my brother lives, the owners association allows a 6x6 dump truck with rigid tandem on their asphalt roads, but not a tractor and 18 ton dumper on a steered tandem with flotation tires. The tractor and dumptrailer have a lower ground pressure and have less sideway friction (when turning)than a rigid tandem, but because it looks bigger, they dont want it..

My brother has to fool them with similar discussions, ground pressure, sideway friction of tandems, to get construction transport near his house... What arguments he uses in the discussion, depends on what transport he needs to get allowed... /forums/images/graemlins/grin.gif

 

[Hambone]

That is exactly what I said. That is what we also do. But, trying to convince will take some actual facts, to them this is hearsay.
I guess they want it in writing from some expert??
Pretty aggravating. So tomorrow I will be traveling 5 1/2 hours one way to get another truck from another division. Such a waste of time and money, unless of course I am wrong about the pressure.

 

[keeney]

Its probably more of a total weight thing. A Dual-Aale truck or trailer will have a lot more total weight than a single-axle.

Most road restrictions are like 7 or 9 tons "per-axle", though, so this doesn't make a lot of sense.

- Rick

 

[timb]

Hmm. To avoid too much tractor-geek status I guess I shouldn't post the spreadsheet I did at one time comparing ground pressure between the old tractors I know and various sized of modern CUTs and utility tractors. /forums/images/graemlins/tongue.gif

I wanted to know how much worse (or better) the ground pressure would be (which is after all the best indicator of potential rut "damage" to the lawn/ground) from what I was used to with the existing equipment.

But I had to guesstimate the contact patch area - never found anywhere that published that spec.

Tim

 

[normde2001]

Talk about ground pressure, I can recall when all farm tractors had iron wheels, and those iron cleats caused some monstrous ground pressure in the asphalt when a farmer would venture onto the highway. /forums/images/graemlins/frown.gif

 

[bigpete]

timb, Absolutely no offense intended. In fact, I consider myself to be a major tractor geek. Self-effacing humor, you know...

I, for one, would like to see your spreadsheet.

 

[Soundguy]

I work alot with the county and DOT road depts ( civil eng... ).. here's there take on this...

They have to categroically deny a vehicle.. that is by class.. not case by case basis. The more axles a truck/trailer has.. the heavier it can be. By saying one rear rigid axle.. they have pretty much limited that road to 26000 pound vehicles.

Otherwise, a semi, with an over dimensional permit and a 50 ton flatbed could roll in with 6 axles, and carry a 112000 pound piece of equipment...

Thos signs are probably like ours that show a picture of a moving van ( uhaul ) and say.. local deliveries only.. or frontage streets only.. etc.

Soundguy

 

[wayneg]

I believe the ground pressure, in terms of force per unit area, will be equal to the tire pressure. This is where the forces will be in equilibrium.

In other words, a tire pressure of 30 psi will have a ground force of 30 psi. The contact area will then be a function of the weight on the tire divided by the tire pressure.

 

[jmc]

Wayneg,

By that logic, the more air you put in your tires, the more your tires sink in.

I think your theory is true if the only source of tire pressure is the vehicle weight. But that only accounts part of the total tire pressure. Most of it is from the air hose, as a preload to keep the tire in a useful shape.

John