You can plug any number in for the front/rear drive ratio, because you aren't going to change it on that particular tractor. ... In fact, you can omit that altogether and divide the existing front R/C into the rear R/C and pick a pair of sizes that maintain or closely aproximate the result when similarly calculated.
You would probably get more help if you gave more detail as to exactly what you are trying to accomplish tire size- and type-wise.
Rick, you're right that I could pick a set of tires that match the ratio of my current tires, if I could find an exact match. What I am trying to do, however, is replace my front turfs with a set of R-4s and the ones that have the same listed size (25x8.50-14) have an RC that is 3 inches bigger. What I am trying to determine, by comparing to the gear ratio, is how much of a change will be tolerated and still be within the acceptable lead/lag percentage (if I could even get THAT information from the dealer).
There's no reason we shouldn't know technical information on machines we own. This is important if we change tires.
I did the same thing with an earlier tractor I owned, it took some time but Deere did get back to me with the information.
I agree, it is kind of frustrating trying to get this information.
I finally got an e-mail back from the dealer saying "
There are no listings on drive train ratio and or wheel lead for any tractor. What size and type of tire do you have on your tractor right now? What size and or type are you looking at putting on your tractor? Sometime if you tell us what your are trying to do we can help better that way." So I replied back, explained about the tire swap I was trying to accomplish, that I had an opportunity to buy some blemished tires at a discount and attached a
copy of the article I linked to in my earlier thread that explained the problem and the formula. Not a word back.
Now, I understand that they are not going to be as helpful because they won't be the ones selling the tires, but they are still the manufacturer's representative and the gatekeeper to the technical information. If New Holland had a direct source of information, then I wouldn't need to bother the dealer, but that is not the system that is in place. It's not like this dealer makes no money off me, I buy all my supplies and parts there.
Anyways, I used the trick that someone on another thread mentioned, jacked up the right side of the tractor, put it in 4wd, and ran it slowly counting the revolutions for the front wheel and the back wheel, to get an approximation of the gear ratio. Using that information I determined that the extra 3 inches in circumference would make enough of a difference that I didn't want to risk it, so I just bought a new set of replacement turfs.
Sorry for the vent.
Thanks for the replies and I hope everyone has a safe and enjoyable holiday!!
Dave
