HST: Rabbit versus Turtle

[tommu56]

I agree with JJ
1) Engine speed to get 540 out pto.
2) Ground speed to give the quality whether its tilling or mowing it doesn't matter.

As for the wear on tires in 4wd I think most tractor tires die from old age (dry rot) or a hole too bad to patch.
The wear on the gears in the front end they are spinning all the time driven from the wheel if not in gear or driven from the transmission if in gear I don't see much difference.

tom

 

[ccsial]

I pull a 5 foot tiller with my 1910 with AG tires. I use 4WD since there are times I spin the tires in 2WD. I am tilling good black dirt. Based on that observation I would use low range to till. I would worry about lugging the hydrostatic in High.

 

[LBrown59]

I would worry about lugging the hydrostatic in High.

Sounds about rite

 

[RadarTech]

4WD vs 2WD--
I live in very hilly terrain.. I am always in 4WD.......
As to the point of High vs low..

there is a major performance and torgue difference..
for the few times I have run in high I have seen the RPM drop way down..
So I would speculate that if you were running a tiller and then hit high gear, it may not keep PTO speed up...

BUT YMMV.....

J

 

[savageactor7]

Some actions require low gear, tilling would be one of them. I move lots of buckets of clay or sand that I use low to load up and high to travel in.

As long as the tractor is level and the shifter slides easily into gear there's no harm done...my 2 cents anyway.

 

[EE_Bota]

When one shifts from high to low, you are not doing so because you do not have enough power, you are doing so because you do not have enough torque.

A hydrostatic transmission usually is a constant torque device, as least as it appears on many Kubotas. The Torque available from the hydrostatic portion is constant because it is limited by the pressure relief valves. When you switch from turtle to rabbit, you are lowering the available torque to the rear wheels, and trading that for speed. Since Power is torque times speed, you are not changing your power at all.

I do not have a tiller. I will not give advice on how to till. However, the OP, even though he is asking a question, seems to be quite right in his ideas of how a hydrostatic transmission works. There is no reason he cannot till in high so long as the tractor torque required does not exceed the pressure relief device limit. If it does, he will see that his speed is no longer proportional to the foot pedal movement, and he will begin to build heat. The heat builds because a pressure drop with flow that does not do useful mechanical work will be transformed to heat.

A reverse tine tiller might be hard to pull, but a forward tine tiller should be easy to pull, or hard to resist being pushed by, depending on how one wants to look at it.

 

[check]

I forgot I was in high on my BX25 last week, and couldn't understand why I couldn't make it up a hill Duh! Anyway, when I have to move snow or spread gravel, high is the way to go, and when digging with the FEL I always go turtle, 4WD, and i hold down the rear wheel lock foot lever at the right moment when traction is likely to be lost. As well, because shifting is so easy I will often fill the FEL in turtle, and then shift to rabbit to drive to the dump spot - saves a lot of time!