# 4wd tire ratios



## tlhtr

Hi folks,
I've been lurking for a while and am in need of some help. I have a YM 336d and have aquired all the manuals, IE; owners, parts, and a dealers service manual (which has been a godsend). I needed to replace the front tires so I looked in the manual and then looked at what was on the YM, didn't match so I did some digging. The problem is, I found info on rolling circumference ratio and even the tires listed in the book have too much lag,* IF *I use the ratio (frt AXLE to rr AXLE speed ratio) listed in the service manual. There are several different ratios listed. If I use the listed front to rear axle ratio (1.4848) times the the frt drive shaft *GEAR-to-BEVEL PINION *reduction ratio (1.2) I come up with a good actual ratio of 1.78. If use that ratio I get a lead of 6 % which according to the info I dug up is fine. If I use the 1.4848 with the listed tires the lag would be -12% which according to the info is NFG shouldn' have *ANY*lag. Any one know if what I have done is correct?


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## winston

Here I am again. Here is a post stating the 336d ratio is 1.694. Whether it is true or not I do not know. 336D Wheels and Tires - TractorByNet.com By going to Nebraska tractor tests I came up with these tire sizes for the 336d. They may or not be correct. I then went to Firestone and retrieved circumference and did the math. rear 12.4-28 = 147", front 8-16 =93". 
93 x 1.694 = 157.542 divided by 147 = 1.0717 - 1 = .0717 x 100 = 7.171% 
Now this may make some sense and maybe not. Might try using the 1.694 with your rolling circumference and see what you come up with.


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## tlhtr

Thanks Winston.
That ratio works nicely. I have 8-16 on front = 91x1.694 = 154.15 /152 (rears 13.6-28) = 1.01 -1=.01x100 = 1.0% . Would seem to me to be perfect, since service manual says 1-4% is the specification. A little lead but not too much. I still am curious why the service manual doesn't list it. It show all kinds of ratios but not that one. Must be some kind of math using two of the ones there, that I don't understand. 
Anyway, Thanks again,


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