Rear rubber

2-70 · Jul 28, 2008

I was wondering how much road speed I'd gain if I switched from 34" rears to 38" rears. Thanks

55 50 Ron · Jul 28, 2008

Roughly 10%

34 inch tire is 106.81 inches in circumference.
38 inch tire is 119.38 inches in circumference.

a ratio of the two tire sizes calculates to about 10%.

Of course a ratio between 34" and 38" calculates to exactly the same!!! Why didn"t I think of that sooner?

55 50 Ron · Jul 28, 2008

If you have a typical 16 MPH tractor, it would increase it's speed to about 17.6 MPH.

matthewh · Jul 28, 2008

Are you talking about the actual height of the tire. If so I am assuming a small tractor with 18 or 20 inch rims. If so a tire that much taller will typically be significantly wider. Check to make sure it will work on your rims. But you would get 11-12% increase in road speed which might not be but 1 mph on those small tractors.

If you are talking about rim size on a larger tractor the % increase will be much less because as even though the rim is 10% larger the tire portion of the overall height will be about the same for the same width tire on either rim. Considering a typical size tire you might use on those rims you would be in the 7% range (considered same width/height tire on both rims). Again about 1 mph and change on those size tractors.

2-70 · Jul 28, 2008

Thanks for the responses... not as big of an increase as I'd hoped.

Anonymous-0 · Jul 29, 2008

The 11.2x24 is 125in around i just measured it an on the B farmall it runs at least 1 mph faster than the 9.5x24. So you are going that much larger it will go peobably 3-4. Friend has 15.5x24 on his B and was clocked at 16 with radar gun when standard B with 8.3x24 went 9 5/8.

Rear rubber

2-70

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55 50 Ron

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