A friend has 180/85D12 tires on the front of a Kubota. That size is hard to find. The info I get for that size is 24.1" high with a rolling circumference of 71. He has found tires in size 600-12 that are 23" high with a rolling circumference of 69. Would it be OK for him to use that size for the 2 fronts or would it mess something up on a 4x4 tractor?
Changing tire sizes.
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millertire
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We can get you a 180/85D12 Titan Tru Power, $198.00 each + shipping. Call 419-335-7010 8am-5pm EST, Mon-Fri. Ask for Ed
Atypical_decorum
Silver Member
Check the lead lag ratio/RCI. If it's still within the acceptable percentage (1% to 5%), you should be fine.
1stDeuce
Gold Member
Most tractors have some front lead, meaning in 4wd the front tires are covering just a tiny bit more ground than the rear. Putting a smaller tire on the front will reduce (or eliminate) that lead, which is better for straight line... My $0.02 is that he'd be fine.
FWIW, I gave my tractor slightly more lead with a tire change and I like it better because most of my 4x4 work is loader work, with a lot of turning. I get no binding at about 1/3 of full lock instead of closer to straight. More lead makes it turn without so much crabbing in 4wd, but going straight I can see the front tires pulling more... I just don't use 4wd going straight on harder surfaces where it isn't needed anyway...
Good luck!
FWIW, I gave my tractor slightly more lead with a tire change and I like it better because most of my 4x4 work is loader work, with a lot of turning. I get no binding at about 1/3 of full lock instead of closer to straight. More lead makes it turn without so much crabbing in 4wd, but going straight I can see the front tires pulling more... I just don't use 4wd going straight on harder surfaces where it isn't needed anyway...
Good luck!
I have a Ford 4500 . I have replaced one of the tires with trelleborg 440/70/24 . I just use for moving hay and mowing . it has been on as a mismatch for over a year. I was just told that it will ruin the seals etc. Is this true. It is an old tractor 1967-1975 It is never on hard sueface
1stDeuce
Gold Member
Assuming the new tire is close in size to the old tire, you're not going to cause any problems running a slight mismatch. No seal problems for sure. (What fool suggested seal problems from a slight tire size difference? Unless the tractor is always leaning 10° to one side, I don't see how any seal would care...) Run it!
Texasmark
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The reason for the front "lead" of a few percent is that keeps the rears from pushing the front around a curve and lets the fronts pull the rears around the curve.