Tire Selection Tire size change on AWD

[aldanbnb]

I have heard that you should not change the size of the rear tires on an AWD
without changing the fronts also. Something about rears pushing the fronts ect.
My question is with 16.9 R 30 on back and 12.4 - 24 on the front can I change one or two sizes on the back without a problem?
I am trying to save a few bucks on tires as deals come up on certain sizes once in awhile.
Thanks

 

[ovrszd]

What does your tractor do now when driven in a straight line in 4wd?? Your info doesn't list a particular 4wd tractor.

If you install a size smaller on the rear the tractor will "pull". The fronts will slightly spin while driving forward in a straight line.

If you install a size larger on the rear the tractor will "push". The fronts will scoot on the ground as the rears push them along when driving forward in a straight line.

Either situation is very hard on driveline and tires.

My Kubota slightly pulls. It will turn shorter in 4wd without pushing the fronts.

My Ford is neutral, easily clicks into/out of 4wd while driving straight forward. It doesn't like to turn short and will push the fronts.

 

[GManBart]

More than anything else, it depends on the exact model, and configuration of tractor. Some brands will provide a chart of tire combinations that will provide an acceptable ratio.

What model tractor is it?

 

[arrow]

I have heard that you should not change the size of the rear tires on an AWD
without changing the fronts also. Something about rears pushing the fronts ect.
My question is with 16.9 R 30 on back and 12.4 - 24 on the front can I change one or two sizes on the back without a problem?
I am trying to save a few bucks on tires as deals come up on certain sizes once in awhile.
Thanks

Most manufacturers seem to offer a 2% change as being still ok. This is designated to tire height as roll out ratios still configure to a safe point with only 2%. If your current tires in back are say 50" in diameter, then you can reduce this diameter by 2% or 1".

 

[aldanbnb]

Thanks Arrow, That gives me something to go on.
It is a Same Explorer 70 with 16.9 R 30 on the rear and I hope that I can go one size larger.
Thanks

 

[ovrszd]

I believe the next size bigger for you will be 18.4x30. Here's an example of what they look like when compared to a 12.4x24.

 

[ovrszd]

you could only use a 480/70R30 (OD of a 16.9x30 is aprox 58.5", a 480/70R30 is 58.4) you could get by using the same wheel, it will be a bit narrow but will work, any wider and taller you would have to convert wheels and tires on both front and rear. I can help you with the correct tire sizes if you want to explore that avenue, $$$$ solves all problems, but you could get some width by using the 480/70R30 aporx 19.3" wide section width.
Steve
531-203-0951

When my front 12.4x24 Titans wear out I'm going metric to gain some width.

 

[budepps3760]

Like your explanation of English terms. Sadly many have lost the basics of communication this day and age.