What is the front/rear gear ratio on an m7040?

[jwill]

I'm curious about tire options and determining just how much overrun I have. I've tried to get the number from my dealer with no luck. Thanks.

 

[ovrszd]

I'm curious about tire options and determining just how much overrun I have. I've tried to get the number from my dealer with no luck. Thanks.

I've not saw that data posted. On my M9540 there appears to be very little. It doesn't act like it binds up when driving in a straight line in 4wd. My previous tractor was an L4400. It had considerable overrun and bound up instantly. You'd have to back up to get it unlocked sometimes. I've saw several posts on here from guys that changed tire sizes on the 7040. If you don't get much response you might start another thread about "changing M7040 tire size" or something catchy like that to get involvement.

 

[jwill]

I've even talked to a couple people at Kubota and can't get a straight answer? I agree that my stock 16.9-30 and 9.5-24 have little to no overrun. I'd like some larger front tires and want to know how much room I have to work with.

 

[case245]

i have a 7040sud i have that set of tires to when i got the tractor the dealer said i could go with the tires from an 8540 if that helps you or not do you have fenders on the front

 

[ovrszd]

I've even talked to a couple people at Kubota and can't get a straight answer? I agree that my stock 16.9-30 and 9.5-24 have little to no overrun. I'd like some larger front tires and want to know how much room I have to work with.

I'll try to quote this and someone can correct me if wrong. The standard tire on an M8540 is 11.2-24 and 16.9-30. The standard tire on an M9540 is 12.4-24 and 18.4-30.

I don't think you would have any issues if changing all four. But, I'm guessing here, I think you are wanting to increase front tire size only?? For me, I wouldn't want to go more than one tire size. Even then you are probably going to creat overrun that will increase front tire scuff and wear. You'll probably also creat what I described about my L4400. It was very hard to get out of 4wd if on solid footing. Any more than one tire size and I think you'd create a driveline stress problem.

Maybe try Google searching for tire specifications. If you could find the running diameter of your 9.5-24s and compare that to the running diameter of the 11.2 or 12.4 for example, you could calculate how much overrun you are going to create. If you do a search and learn anything, please post the data as others will be interested.

I'd like to have the Canadian or European style fronts on mine, they are metric sized. They are considerable wider but I think the same diameter. Might also be something for you to Google search.

 

[jwill]

Yep, I've thought about the european style fronts.

I've done a ton of calculating on this and how the numbers work, EXCEPT, I don't know the gear ratio of the tractor.

Ex, rolling circumference wise, 11.2-24 will increase the overrun approximately 4% over 9.5-24. If with 9.5-24 it was at 0 or 1% it would be fine, but not if it was already at 3 or 4%. So, that's my dilemma.

 

[94BULLITT]

If you new your transmission gear ratios you could use a gear calculator to get close. Punch in your tire diameter, rpm at a given speed and your transmission, and the transfer case ratio would be your High/ low ratio.

Planet 4x4 - Gear and 4x4 Calculators

 

[jwill]

Anybody know? I can't believe it's so hard to get the gear ratio. At first I thought it was my dealer just being lazy, but I can't get a good answer from Kubota either.

 

[sixdogs]

I did the swap with an M8950 and got the info from a tractor tire dealer and I believe he got the info from a Firestone book. Not sure but the tire dealer had a book and looked up my info. As well, Firestone had a whole batch of computational info online and it really helped.

This info is out there and either a tire dealer or Kubota itself have the #'s. Your dealer likely won't know since it's something he wouldn't ever need to know. You can also just type in info needed in Google and see what pops up. I swapped tires on my JD 5520 and I fould the info there first and then double checked it elsewhere.

I can't recall but think Kubota liked a 3-5% front tire "pull" advantage.

 

[sixdogs]

It's an old thread but I just found where Deere keeps it's front-rear axle ratio.
This ratio is where all the tire size plans should start.

Doesn't sound right but on the back of the seat?

OMSU41643

Now the search is on for Kubota info.