Kubota L275DT Front to Rear gear ratio

[kitaps]

Hello guys,

the time has come that my old 1981 Kubota L275DT need new tires.

The problem lies in the fact that my Kubota had Turf tires, but what I need is farm tires, it means I have to change rims. Since the tractor is so old and I am located in Eastern Europe, where such an on japanese machine is quite a rarity I have to improvise. For the rear axle I have already modified rims from Yanmar(I think) and put 9.5x24" tires on. I chose 9.5 because 11.2 are to wide for my application. But in front I want to modify existing rims and put 6.5/80-15 on.

I have calculated diameters and circumferences from different tires which were put on L275DT by the specification. I get numbers inbetween 1.44 - 1.5.


The question for you guys is - Maybe someone knows the actual front to rear gear ratio? I looked through internet and some manuals, I couldn't find it.

There is no proper dealer here, where could I ask such a thing.
I need this ratio because different tire manufacturers for e.g. - 6.5/80-15 tire have different diameters/circumferences. That way I could be more sure to have adjusted tire sizes more properly.

Thanks

 

[Alexisferos]

by the information i found at the internet you need
Ag front:
7-16 (4WD)
Ag rear:
11.2-24
with the modification at rears you are ok, now you need a 7-16 at the front.

 

[kitaps]

Yes, original sizes. Except I have and need 9.5-24 it has smaller rolling circumference than the 11.2-24.

I have calculated correct size for my front tires which is 6.5/80-15 - I only wanted to do some fine tuning to decide which model to buy, because they differ in rolling circumference.

If I had the actual data from Kubota, I would be able to assure which exact make/model tires to buy.

 

[North Idaho Wolfman]

6.5/80/15 is way too small and would trash the 4wd in a matter of seconds, as it's 13% off ratio.

Ratio is as follows:
Stock
Front: 7-16 RC 87
Rear: 11.2-24 RC 129
Ratio: .67

Your proposed setup:
Front: 6.5/80-15 RC 67
Rear: 9.2-24 RC 123
Ratio: .54

What your setup should be:
Front: 7-15 RC 83
Or
Front: 8.0/75-15 RC 83
Rear: 9.5 - 24 RC 123
Ratio: .67

Yes I realize that the numbers are in inches and your used to metrics but they will give you the same results, your side of the pond or mine.

 

[kitaps]

Oh yeah, you are right. Thank you!

 

[clay45]

I recently learned that the Drive Train Ratio (DTR) on my L2050DT is 1.636. And that I should use the static load ratio (SLR) when available and the rolling circumference (RC) when its not. After that use what you can I suppose since it is now obvious to me you cannot depend on having the spec you want available on all tires.

I've also come to the conclusion you cannot depend upon the tire sizes as issued originally as a definitive method to establish a ratio.

If you know the SLR or RC for the 9.5-24's the formula I have for finding the appropriate front is F=(Rear / DTR) x 1.05. "1.05" is the middle of at 1.03 - 1.07 tolerance range. "Rear" is either the SLR or RC for the tire you have.

Good luck.

 

[tiredguy]

Wolfman nailed it perfectly so get the front tires he said to keep the
ratio correct at .67.
Great job Wolfman!
Al

 

[clay45]

kitaps,

You don't say what your rear tires are but some information I have you might find useful is:

Titan Hi-Trac 48D665 size 7-14 tires : RC 83 SLR 12.7
Titan 495694 size 9.5-24: RC 124.0 SLR 19.2

BKT TR-171 9.5-24 RC 121.3 SLR 19.7
BKT TR-135 9.5-24 RC 126.7 SLR 19.4

Bridgestone Farm Service Lug F RC 124.0 SLR 19.2 don't know if still available

Good luck!