Don't leave 4wd engaged all the time

[rbargeron]

Noticed this on a tractor with 900 hrs. If yours runs on pavement a lot, take it out of 4wd !

 

[19thSF]

Noticed this on a tractor with 900 hrs. If yours runs on pavement a lot, take it out of 4wd ! View attachment 60881

Good advice! In four wheel drive, the front tires are "geared" to cover slightly more ground than the rears, so as to provide steerage on soft ground. . The front are "pulling" the rears just slightly. That is OK in mud or other slippery stuff. On pavement, with use, you get the result you show in your picture. One note. The preceding only applies if the tires (front and rear) are sized within manufacturer's spec. Kubota does not publish it, but if you request, you can get your tractor's "gear ratio". With that in mind, you can determine what tire sets (front & rear) will work properly with the ratio.

You provided an outstanding example of the result of what can happen to your very expensive front tires. A great lesson for others to keep in mind.

 

[rbargeron]

....Kubota does not publish it, but if you request, you can get your tractor's "gear ratio".

The information needed can be found in the Illustrated Parts Lists. The tooth count is given for each gear in the system. Following it through from rear pinion to both axles the number of front turns for each rear turn can be figured. Its called "Transference Ratio". For my L5450 it's 1.51 : 1 and for my L48 it's 1.54 : 1

To find the actual degree of "scuffing" going on, multiply this number by the circumference of your front and back tires. You'll get two distances (front distance traveled is slightly larger). That's the "Inter-axle Ratio". For the L5450's its 1.04 : 1 and for the L48 its 1.03 : 1

More related discussion here - starting at Post #18.

 

[Matt Ellerbee]

We have an MX5100 at work with just over 400 hrs. It is on its second set of turf tires from being "stuck" in 4wd. Previous operators (many) never washed the machine after fertilizing. Rusted most levers solid. It has since been fixed and new operators told to wash thoroughly after fertilizing. We shall see...

 

[19thSF]

The information needed can be found in the Illustrated Parts Lists. The tooth count is given for each gear in the system. Following it through from rear pinion to both axles the number of front turns for each rear turn can be figured. Its called "Transference Ratio". For my L5450 it's 1.51 : 1 and for my L48 it's 1.54 : 1

To find the actual degree of "scuffing" going on, multiply this number by the circumference of your front and back tires. You'll get two distances (front distance traveled is slightly larger). That's the "Inter-axle Ratio". For the L5450's its 1.04 : 1 and for the L48 its 1.03 : 1

More related discussion here.

Hello rbargeron,

Thank you for the further explanation.

 

[rbargeron]

Some Owners Manuals list the ratio - others give tire sizes for the model.

 

[GeoHorn]

Look thru your Owners Manual and the compatible tire-sizes are listed for your model.
Example:

 

[19thSF]

Look thru your Owners Manual and the compatible tire-sizes are listed for your model.
Example:
View attachment 60887

Thanks Geohorn

 

[19thSF]

The information needed can be found in the Illustrated Parts Lists. The tooth count is given for each gear in the system. Following it through from rear pinion to both axles the number of front turns for each rear turn can be figured. Its called "Transference Ratio". For my L5450 it's 1.51 : 1 and for my L48 it's 1.54 : 1

To find the actual degree of "scuffing" going on, multiply this number by the circumference of your front and back tires. You'll get two distances (front distance traveled is slightly larger). That's the "Inter-axle Ratio". For the L5450's its 1.04 : 1 and for the L48 its 1.03 : 1

More related discussion here.

Hey rbargeron,

A little help please. I just went into the Illustrated parts for my B2650 Hydrostatic. I can find the gears and the respective part numbers, but I can't find a reference to "tooth count". Where should I be looking?

 

[rbargeron]

Often in the part name column, or in the remarks column

 

[twomany]

Noticed this on a tractor with 900 hrs. If yours runs on pavement a lot, take it out of 4wd ! View attachment 60881

Hmmm If were a road vehicle... like a car....

900 X 40 (miles per hour average "guesstimate") = 36,000 miles.

Not too shabby for a passenger car tire much less a tractor.

The tractor will certainly see less "mileage", but the conditions of use are rough. Fronts always wear the fastest anyway.

 

[rbargeron]

Different situation - a large amount of tread depth has been abraded away in the post #1 pic.

 

[19thSF]

Different situation - a large amount of tread depth has been abraded away in the post #1 pic.

Just for informational purposes, here is what I received from Kubota customer service when I asked about the front to rear axle RPM ratio. I believe that the ratio they refer to as "Gear Ratio" is the front to back axle RRM ratio. Would you agree?
Thanks!

 

[rbargeron]

Applying the chart's 1.672 ratio to the circumferences of the 2 tire sets listed in Tractor Data for the B2650 shows the fronts pulling about 8% in one case and 9% in the other. The difference is less on other machines I've looked at - but maybe smaller rigs want more lead?

I tried to verify it by counting gear teeth through the machine from the parts lists, but I need more detail on the front driveshaft gearing at the clutch housing. I'll look at a WSM to figure out which shaft does what and report back. (good thing I'm retired )

 

[GeoHorn]

Hmmm If were a road vehicle... like a car....

900 X 40 (miles per hour average "guesstimate") = 36,000 miles.

Not too shabby for a passenger car tire much less a tractor.

The tractor will certainly see less "mileage", but the conditions of use are rough. Fronts always wear the fastest anyway.

40 mph for a tractor is supersonic.... a more likely average speed would be 1-3 mph.... so 1800 miles, using your calculus (not considering the larger O.D. of a tractor tire...which would further reduce the number of revolutions/tire-wear-factor....all of which presumes the tires were installed the same time and are same age as the rears.)

 

[rbargeron]

EDIT - found my error.
19thSF - The "gear ratio" given on the list ---IS supported in the WSM. The 2013 version of the WSM for B2050 B2350 B2650 B3150 covers all the options - including Bi-Speed Turn, where the amount of front "pull" jumps up on sharp turns . Was that list tied to your serial number?

 

[twomany]

40 mph for a tractor is supersonic.... a more likely average speed would be 1-3 mph.... so 1800 miles, using your calculus (not considering the larger O.D. of a tractor tire...which would further reduce the number of revolutions/tire-wear-factor....all of which presumes the tires were installed the same time and are same age as the rears.)

You are making the comparison in a way that was not intended. But hey. It's someone else's tire.

We need a "Show your tires with 900 hours on them" thread.

I'm not worried about 4WD use as a major factor in tire life. I use 4WD because it is needed! The wear and tire replacement cost is just part of operation. I never think to myself, "Gee, I better take it out of 4WD or my tires won't last 900 hours.

nb. The tractor I use most has a locking differential in the front axle. That will cause some wear if left engaged on hard surfaces ;-)

 

[19thSF]

19thSF - The "gear ratio" given on the list doesn't appear to be supported in the WSM. The 2013 version of the WSM for B2050 B2350 B2650 B3150 covers all the options - including Bi-Speed Turn, where the amount of front "pull" jumps up on sharp turns . Was that list tied to your serial number?

19thSF - The "gear ratio" given on the list doesn't appear to be supported in the WSM. The 2013 version of the WSM for B2050 B2350 B2650 B3150 covers all the options - including Bi-Speed Turn, where the amount of front "pull" jumps up on sharp turns . Was that list tied to your serial number?

I di not mention a serial number. I have attached my inquiry. When I asked them what they considered as the correct lead, they answered with "acceptable tires"

 

[woodsy]

Disengaging 4x4 is OK as long as you remember to reengage gauge it
for appropriate tasks. I had forgotten to reengage mine the other day
and going down a hill with bucket load of gravel started picking up speed
when the rear tires started slipping, hit brakes started going faster .
Dropping the bucket saved me, crept down the hill with bucket down, whoops.

 

[rbargeron]

19th SF - does your B2650 have the Bi-Speed option? From the WSM it doesn't affect any other gearing, only kicks in at high steering angle - so shouldn't be a factor here.

I finally did verify the front-to-back axle ratio Kubota gave you, using parts lists and the WSM. I had misread the tooth count on the rear axle gear. All checks out now.