Equipment Ground Pressure

[Forest Meister]

I am working with a landowner who is absolutely adamant that an empty 5 axel forwarder with 22" tires that used his gravel driveway caused depressions in the tread ways that were not there prior to the single trip of the equipment.  No matter how I look at it I can see nothing that even resembles any new depressions. 

Not sure facts will work on this guy because he dismisses the obvious  fact that the skidder was much wider than the existing "ruts" that he is trying to blame on the equipment.  That aside, does anyone know of a simple and straightforward website that lists the general psi ground pressure of wheeled logging equipment?  I can find the psi ground pressure for cars and trucks (25 to 30 psi) but nothing reliable for logging equipment.

Any help on this would be greatly appreciated. FM

[barbender]

What do you mean by a 5 axle forwarder? I have seen 4, 6, and 8 wheeled forwarders, and Ponsse does make a 10 wheeled model. You might check Ponsse's website for ground pressure specs of their various models. It sounds like the landowner is trying to get some free road work, so I don't know if it will make much of a difference.

[g_man]

I am pretty sure the ground pressure of wheeled vehicles is the same as the tire pressure. As you increase the load the tire flattens out to give you more area contacting the ground but the tire psi and ground pressure remain the same.

gg

[John Mc]

I am pretty sure the ground pressure of wheeled vehicles is the same as the tire pressure. As you increase the load the tire flattens out to give you more area contacting the ground but the tire psi and ground pressure remain the same.

I've heard that as well, but I've also heard that that only refers to ground pressure at the surface. It's supposedly different as you go below surface pressures. Not sure whether that makes a difference or not in this case. The whole point of multi-axled forwarders is to reduce ground pressure when fully loaded. Not sure how it could cause ruts in a gravel driveway when empty.

[Holmes]

 I do a general surface area on the ground and divide it by the weight of the vehicle.  Lets say you have 10" wide tires and they have 10" of tread sitting on the ground, 10x 10 = 100 square inches.  4 tires times 100sq." = 400 sq. inches on the ground supporting a 12,000 lb vehicle, = 30 pounds per square inch ground pressure.  Same vehicle with heavy lug tires, tractor tires, with half the surface area contacting the ground 50 sq. inches x 4 tires = 200 sq. " on the ground  12,000 divided by 200 = 60 pounds per square inch of pressure on to the ground.  That is why the lug type tires imprint into surfaces.

[treeslayer2003]

i think holmes is right. i won't do the math but i'd say under 10psi is around what you are dealing with. i can tell you a empty skidder [540] with 28s will almost walk on water.

[Gearbox]

I thought that I read a 1270 TJ was about 7 or 8  that may have been with the tracks on Loaded 8 wheel fordwarder can't be much more . Gearbox

[chevytaHOE5674]

On a soft dirt woods road my 3/4 ton diesel pickup leaves deeper tracks than our empty 8 wheel forwarder.

[lopet]

All nice and good, but I doubt that all this math explained to somebody with no common sense will not have an impact.
Good luck on that one .

[treeslayer2003]

i am sure that land owner is looking to get his road fixed for free. ya run into that kind every so often.

[teakwood]

A foot from a human has more ground pressure than that empty forwarder!

[Gadrock]

I do not know the psi info, but I can tell you we DO NOT ALLOW SKIDDERS ON OUR ROADS IF WET.

a skidder will ruin a road in no time flat. The one I use now has 30.5 tires and only weighs 33000 and many of the others like T Cat and Caterpillar weigh lose to 40000, depending on which model and angle of the stars and moon.

see if you can settle the problem with a quick workover with the dozer. And get your local forester to be a witness along with pictures. Sometime it is a matter court decisions, where a professional's view and witness could be compelling info.

david g

carry on

[chevytaHOE5674]

a skidder will ruin a road in no time flat.

That's a skidder not a forwarder. Skidders are made to "bite" into the ground and pull the wood where a forwarder is made to float and carry the wood on its back.

[sandsawmill14]

I am working with a landowner who is absolutely adamant that an empty 5 axel forwarder with 22" tires that used his gravel driveway caused depressions in the tread ways that were not there prior to the single trip of the equipment.  No matter how I look at it I can see nothing that even resembles any new depressions. 

Not sure facts will work on this guy because he dismisses the obvious  fact that the skidder was much wider than the existing "ruts" that he is trying to blame on the equipment.  That aside, does anyone know of a simple and straightforward website that lists the general psi ground pressure of wheeled logging equipment?  I can find the psi ground pressure for cars and trucks (25 to 30 psi) but nothing reliable for logging equipment.

Any help on this would be greatly appreciated. FM

if it was me i would give him a couple loads of gravel upon him signing a release that he was satisfied. thats just to save the headache because if there is no damage he cant do anything but complain but the way it sounds a couple loads of gravel is probably what he is after and he is just being a smiley_smelly_skunk (not the animal i was looking for but it'll work ;D ) maybe you will get it worked out fairly easy but i would not be out alot of money to satisfy him if you did nothing wrong. GET SEVERAL PICS OF HOW IT IS NOW in case he does try to cause you trouble. i had a round with a doctor 1 time over a chipped  brick >:( those pics could be prices in the end. ;)
by the way he still has a chipped brick and thats been over 10 yrs ago :D :D ;D

[John Mc]

If you are certain he has no valid reason for demanding you fix his road, I don't know that I would be giving this guy anything, unless you feel there was some way your activity caused it.  If you offer to give him gravel, it could be taken as an admission of guilt, and subject you to further obligations (grading the gravel or?).

Offering something where nothing is owed will just encourage him to pull this stunt on the next guy, and may encourage others to make similar demands.

[edited to correct typos]

[sandsawmill14]

If you are certain he has no valid reason for demanding you fix his road, I don't know that I would be giving this guy anything, unless you feel there was some way your activity encouraged it.  If you offer to give him gravel, it could be taken as an admission of guilt, and subject you to further obligations (grading the gravel or?).

Offing something where nothing is owed will just encourage him to pull this stunt on the next guy, and may encourage others to make similar demands.

this is a very good point

[John Mc]

I'll admit I'm rather stubborn/biased in this area. I'm happy to try to work out a compromise with someone who is willing to discuss things rationally, and has at least some basis to make their claim. However, if someone is just being a jerk, trying to pull one over on me, or threatening me, I'll spend several times the amount in question (in both $ and in my own time) just to make sure th ejerk doesn't get away with it.

[treeslayer2003]

I'll admit I'm rather stubborn/biased in this area. I'm happy to try to work out a compromise with someone who is willing to discuss things rationally, and has at least some basis to make their claim. However, if someone is just being a jerk, trying to pull one over on me, or threatening me, I'll spend several times the amount in question (in both $ and in my own time) just to make sure th ejerk doesn't get away with it.

x2

[barbender]

I'll admit I'm rather stubborn/biased in this area. I'm happy to try to work out a compromise with someone who is willing to discuss things rationally, and has at least some basis to make their claim. However, if someone is just being a jerk, trying to pull one over on me, or threatening me, I'll spend several times the amount in question (in both $ and in my own time) just to make sure th ejerk doesn't get away with it.

X3

[John Mc]

... I'll spend several times the amount in question (in both $ and in my own time) just to make sure the jerk doesn't get away with it.

Which may be a bit odd, since I'm also the guy that is usually seeking common ground and trying to find solutions that everyone can live with.

[Forest Meister]

To close out the job and be done with it the logger and myself we put thirty yards of gravel along about eight or nine spots the length of the half mile long driveway where the owner said the empty forwarders with 24" tires made depressions a foot or less wide in the tread ways.  A dozer spread the gravel where it was "needed".  In the end he appeared to be happy as a hog in mud. 

But just as we all expected the guy is still not letting facts change his mind about the "damage" caused by the evil forwarders.  Odd thing though, the loaded gravel trucks had to drive in the tread ways the full length of the road so they could turn around and drop gravel on the way out.  Not a word was uttered about that and I believe we are talking about more weight than the empty logging equipment.  As my mother used to say when I was a kid:  "It takes all kinds to make the world go 'round".  FM

[edkemper]

Perhaps it's gotten to a point where buying a GoPro camera to document your work is in order. Transfer the video to a DVD and go to the next project. Keep the DVD's in storage in case of future problem.