Air Pressure in Loaded tires.

[Diamondpilot]

I agree with most here. I bring mine up to the normal pressure. Just pull the tractor with the valve stem at 12 o'clock and check them.

Chris

 

[Movintgt]

I may be making a stupid point but here goes! What about the extra weight exerted on the tires when you have something on the 3PH? I'm thinking along the lines of say a 400 pound implement whose center of gravity is say 5 feet behind the axil of the tractor. If my memory serves me, the torque on the axil/tires would now increase by 2000 pounds. Wouldn't that cause some bulging of the sidewalls and thus wear on the outsides of the tire. I imagine that it's not much of a problem when the implement is engaged with the ground but when you are transporting or say moving 600 pound hay bales on a bale spear for some distance, wouldn't you want the tire pressure more in line with a load and not so much an empty tractor. And not to put too fine a point on it, the torque with any load increases a great deal when bouncing around during transport. Could that cause problems if the pressure is too low? Please tell me if I'm over-thinking this!

 

[Mace Canute]

Movintgt, that's correct. Tire pressures need to vary with the weight they support. This is easily evident when you think of the front tires on a tractor with a FEL compared to the ones on a tractor with a 3PH mounted implement. What's correct for one is totally inappropriate for the other. It holds true for rear tires as well, of course.

I posted this before in this thread, post#16 to be exact...

"Tires are designed to operate at maximum efficiency when they are at their Rated Deflection. With the tractor on a hard surface, deflection is the distance from the axle center to the ground surface divided by the distance from the axle center to the top of the tire. In technical terms, deflection is the value of the loaded radius of the tire compared to the unloaded radius. Rated deflection is the amount of deflection when the tire is deformed to its optimum or design footprint. Rated deflection for radial tires is about 85%, for bias tires it is about 90%. The correct pressure to achieve rated deflection depends on the load the tire is carrying. A correctly inflated radial tire will have a significant sidewall bulge or "cheek'. It may look low or flat but it is not. If you inflate a radial tire by "eyeball" until the sidewall bulge looks like that of a bias ply tire, you lose most of the performance advantages of the radial tire."

 

[Soundguy]

wow.. and to think all these years I've just looked at the tire on the ground and aired it up till it looked good and went about my work.

no micrometer.. no tricorder.. no crystal ball.. and not nearly as much thought about it as going on here ???

soundguy

 

[RickB]

wow.. and to think all these years I've just looked at the tire on the ground and aired it up till it looked good and went about my work.

no micrometer.. no tricorder.. no crystal ball.. and not nearly as much thought about it as going on here ???

soundguy

You & me, Sounder. You'd think our tires wouldn't last a week.

 

[Soundguy]

After reading this thread, I'm expecting to go home and find all my tractor tires flat.. especially the loaded ones..

soundguy

 

[Movintgt]

Mace
Thanks for reminding me to read posts closer, or at least when I'm not on the phone.

 

[SPYDERLK]

You & me, Sounder. You'd think our tires wouldn't last a week.

Bet your valves last longer tho.
larry

 

[Don87]

Movintgt, that's correct. Tire pressures need to vary with the weight they support. This is easily evident when you think of the front tires on a tractor with a FEL compared to the ones on a tractor with a 3PH mounted implement. What's correct for one is totally inappropriate for the other. It holds true for rear tires as well, of course.

I posted this before in this thread, post#16 to be exact...

"Tires are designed to operate at maximum efficiency when they are at their Rated Deflection. With the tractor on a hard surface, deflection is the distance from the axle center to the ground surface divided by the distance from the axle center to the top of the tire. In technical terms, deflection is the value of the loaded radius of the tire compared to the unloaded radius. Rated deflection is the amount of deflection when the tire is deformed to its optimum or design footprint. Rated deflection for radial tires is about 85%, for bias tires it is about 90%. The correct pressure to achieve rated deflection depends on the load the tire is carrying. A correctly inflated radial tire will have a significant sidewall bulge or "cheek'. It may look low or flat but it is not. If you inflate a radial tire by "eyeball" until the sidewall bulge looks like that of a bias ply tire, you lose most of the performance advantages of the radial tire."

My point exactly.

 

[pat32rf]

When I got my JD new, some kid(?) at the dealership had inflated the tires to the pressure rating on the sidewall. That lasted about 100yds when the seat switch kept shutting things down everytime I hit a bump.....Since then (4000hrs) they have been inflated to where they "look right", (except for a few times when they got flat on the bottom due to various foreign items.)