Why no hydrostatic transmissions on larger tractors?

[Indian Territory]

Probably a question everyone knows the answer to … except me: Why are there no hydrostatic transmissions on larger tractors?

 

[jeff9366]

There is little need for heavier tractors to be maneuverable, in terms of frequent changes from forward to reverse.

Some 90% of new compact tractors are sold with Loaders.
Once tractors reach 7,000 pounds bare weight, only a few are sold with Loaders.

Instead, the improved fuel efficiency of a geared tractor is important in field use raising crops for profit.

 

[rScotty]

There is no need for heavier tractors to be maneuverable, in terms of frequent changes from forward to reverse.

Instead, the improved fuel efficiency of a geared tractor is important in field use raising crops for income.

I think that's the reason. Because on big 300hp machines like loaders you do see HST transmissions, so there are applications where HST makes sense. Those big loaders have to do a lot of back and forth with maneuvering.

Tractors with geared transmissions often have hydraulic shuttle shifting and power shifts. So that shifting is easier, but once in gear they have the same efficiency as any straight gear transmission.

 

[LouNY]

Mainly because of the heat generated, the noise, the inefficiency, and short lives.
More horsepower aggravates and increases all of the above.
The new CVT and IVT transmissions do use a small hydrostatic drive incorporated
into the transmissions planetary gearsets and bands to provide the last bit of varible speed in addition to the several clutch packs and gear sets.
It is a very limited hydro in respect to it's speed range to reduce all the above.

I haven't run any large loaders in several years but they did not have hydrostatic transmissions at that time they had multiple speed transmissions with torque converter drives.

 

[amhicks21]

Ive been hoping someone comes out with a 80-100hp hst tractor ever since i started plowing snow with the l6060. It make sense in mid size ag tractors to not offer hst's but i can still dream.

 

[Bavarian]

Ive been hoping someone comes out with a 80-100hp hst tractor ever since i started plowing snow with the l6060. It make sense in mid size ag tractors to not offer hst's but i can still dream.

You can get a hydrostatic tractor from 70 to 500 hp if your pockets are deep enough. Look at Fendt Vario.

 

[amhicks21]

You can get a hydrostatic tractor from 70 to 500 hp if your pockets are deep enough. Look at Fendt Vario.

I guess I should've said "someone with dealer support near me". Fendt certainly makes some incredible stuff but ive never even seen one in person locally.

 

[LouNY]

You can get a hydrostatic tractor from 70 to 500 hp if your pockets are deep enough. Look at Fendt Vario.

I do not believe that these are hydrostatic transmissions they are the IVT style which does use a hydrostatic component.
But they are not a straight hydro.

 

[Bavarian]

I do not believe that these are hydrostatic transmissions they are the IVT style which does use a hydrostatic component.
But they are not a straight hydro.

Watch their video. It explains how it works. At full speed, it's gear driven. Anything slower is hydrostatic. No plaetary gear involved like others.

 

[newbury]

IIRC hydrostatic wasn't even offered on the 45+HP Kubota tractors till the mid 1990's or later.