TIRES

[maddog2020]

The John Deere 4066r which is the new equivalent to the 4720 is available with the larger 19.5x24. Just thought if I was going to replace the tires I would go with the larger ones. Probably wont gain anything other than to have bigger tires.

 

[RayIN]

Or look up the RC (rolling circumference) of the tire, which is effective circumference taking into account expected tire bulge.

Would that not be entirely dependent on inflation pressure?

 

[hayden]

Would that not be entirely dependent on inflation pressure?

Yes, and I expect it's based on the recommended pressure based on carrying weight. Measuring the diameter with a tape will depend on pressure as well.

 

[sandman2234]

Put a mark on the tire at the bottom of the circle and mark the ground at that point, then drive it forward till the mark is in the same spot and mark the ground again. Measure between those marks on the ground an you will have the rolling circumference.
David from jax

 

[CobyRupert]

Knowing the actual rolling circumference is the best way to know how you will be changing the tire speed (for a given gear, and the ratio with the front tires when in 4wd). If the tires are 3” taller the most the circumference can change is 3(pi) inches, or about 9.42 inches, or less.

…but why are the tires taller? Wear? Aren’t new just wider?

 

[dodge man]

Taller tires are usually considered better are’t they? Better traction? Otherwise big ag tractors would be running smaller tires. I went from a Kubota BX to a JD 2025r instead of a 1025r for the bigger tires. In the OP’s case it might not be worth the effort and expense to go bigger but I understand why he might want to.