repete
Veteran Member
Lets assume that from the factory with new tires, both front and back are matched in rolling speed. The front tires are is in sync with the rear tires.
If we use the formula R (tire radius) times 3.14152 (Pi) then we get circumference. Lets say the tires when new, with no load in the bucket, have a radius of 15" on the tractor. That gives us a circumference of 47.178 inches. Remember that at this point the gearing is perfect to match the rolling speeds of both front and rear axles.
Now lets say we have used the tractor for a few years and the tires are down by maybe 3/4" in tread height on the front. Let's further assume you have 400 pounds in the bucket causing the tires to "squish" under the weight maybe 3/4". That gives a combined reduction in the radius of 1.5"
Again using the circumference formula but changing the radius to 13.5" we get a circumference of 42.410 inches.
There now exists a conflict in rolling axle speed between front and rear. This will be taken up by one or the other axle forcing the tires to skid on the ground surface (the ground covered must be the same). By shifting out of 4WD you eliminate the conflict and allow each axle to have independent rolling speeds.
I use 4WD only when I need it.
My two cents.
If we use the formula R (tire radius) times 3.14152 (Pi) then we get circumference. Lets say the tires when new, with no load in the bucket, have a radius of 15" on the tractor. That gives us a circumference of 47.178 inches. Remember that at this point the gearing is perfect to match the rolling speeds of both front and rear axles.
Now lets say we have used the tractor for a few years and the tires are down by maybe 3/4" in tread height on the front. Let's further assume you have 400 pounds in the bucket causing the tires to "squish" under the weight maybe 3/4". That gives a combined reduction in the radius of 1.5"
Again using the circumference formula but changing the radius to 13.5" we get a circumference of 42.410 inches.
There now exists a conflict in rolling axle speed between front and rear. This will be taken up by one or the other axle forcing the tires to skid on the ground surface (the ground covered must be the same). By shifting out of 4WD you eliminate the conflict and allow each axle to have independent rolling speeds.
I use 4WD only when I need it.
My two cents.