Tire Tread and Gear Ratios

[RobertN]

Not sure about your application, but when I switched my old Kubota B8200 from R3 turf to R4, the rim size was different was different for turf vs R4. I looked at R1 and the rim size for the factory spec tire was a different size rim too(R1 was narrower tire and rim front and rear).

And, all of those setups varied in height, so matching tires and rims had to be right or else the overall gear ratio would be wrong and cause front end wear.

 

[IH3444]

Alliance 550 Multiuse R-4 Tires | Farm Tire Warehouse

Alliance 550 Multiuse R-4 Tires. Agricultural R-4 Industrial Tractor/Construction Radial tire Developed for Specific Applications on Industrial Tractors, Backhoe Loaders, Municipality and Industrial Tractors dealing mostly with Transport on Hard Surfaces and Compact Construction Machinery.

www.farmtirewarehouse.com

 

[oakhilltop]

It sounds like replacing all four tires of any tread pattern with four new tires of the same size of a different tread pattern may not always work. And maybe even the same tread pattern could be a problem. This seems really f'd up to me. Kinda like bicycle tires where a 26 x 1.75" tire and a 26 x 1 3/4" tire are different sizes.

But it's very possible that I'm still not getting it.

 

[dadohead]

You can figure the ratio by knowing rolling circumference of both front and rear tires then applying the axle ratio the manufacturer uses.
The equation: rc of front x ar, divided by rc of rears.
This will fall anywhere between 1-5% depending on manufacturer.

When I designed tractors at Deere... we'd use SLR: static loaded radius. In later years it got more difficult to get precise numbers from the manufacturers on their tires. Suppliers moving out of the segment? Production moving to low cost countries?

 

[LouNY]

When I designed tractors at Deere... we'd use SLR: static loaded radius. In later years it got more difficult to get precise numbers from the manufacturers on their tires. Suppliers moving out of the segment? Production moving to low cost countries?

The SLR is what I still look for when looking at tires, I have always been surprised that the SLR and the rolling circumference (RC) almost never agrees with the (2πr) with the loaded rolling circumference always being a bit over the loaded radius x 2 x pi., but always a long way from the diameter x pi.

which is what I can change with tire pressure.

 

[SPYDERLK]

The SLR is what I still look for when looking at tires, I have always been surprised that the SLR and the rolling circumference (RC) almost never agrees with the (2πr) with the loaded rolling circumference always being a bit over the loaded radius x 2 x pi., but always a long way from the diameter x pi.

which is what I can change with tire pressure.

Growth of squirm losses within the contact patch.

 

[dadohead]

With the center of the rear axle being the origin (0,0,0) of the tractor model, the SLR determines the "ground plane".... all the lift systems relate to ground. Pretty big deal getting a good SLR number.

"Grown tire" is another number the tire manufacturers used to provide... not so much in recent years. Tires, of course, grow with age. Need to know how much to keep fenders, belly mowers, etc out of their path!