How does an HST compare in pulling power with the same tractor and a gear trans?

[seville009]

I have owned gear and HST. No idea how much HST costs at the wheels but for many the convenience of HST is worth the loss of power. I happen to me one those who will gladly give up a little HP for the convenience.

Agree 100%

Had a small Kubota B7500 hst. Needed a bigger tractor, so went with a geared MF1540 since it was a few grand cheaper than an HST one.

Absolutely hated the geared tractor; was a pain to use for my type of work. Traded it in for the exact same tractor but HST within a year. Much happier. No noticeable difference in power - brush hogging, tilling, snow blower, dirt moving, etc with four fiam filled tires.

 

[K5lwq]

Here is something to consider. HST might out pull a gear tractor in certain situations. Let's say we want to skid a big rock. The goal is to not spin the tires so you have maximum force on the rock.

I would think that being able to infinitely adjust power to the wheels in the hands of a skilled operator, would out perform a gear tractor. But what do I know, I have never owned a HST tractor.

 

[Tx Jim]

Any time an ""engine must pump oil to transfer power"" to rear wheels one loses efficiency & torque transferred. Same situation with a pickup truck utilizing standard vs auto trans.

 

[Mat4644]

On a tractor with HST transmission expect at least 10% less HP to the wheels vs it's geared counterpart. If one is able to utilize the extra power before breaking traction is a different issue. Plus as the HST transmission ages and wears efficiency losses increase. These losses are well known and derived from extensive testing.

The effect on PTO output are obvious in the manufacture posted numbers.

 

[Egon]

Here is something to consider. HST might out pull a gear tractor in certain situations. Let's say we want to skid a big rock. The goal is to not spin the tires so you have maximum force on the rock.

I would think that being able to infinitely adjust power to the wheels in the hands of a skilled operator, would out perform a gear tractor. But what do I know, I have never owned a HST tractor.

I値l agree with that. In hilly tillage situations the hst should also preform a little better as the engine rpm can be kept constant.

 

[Sawyer Rob]

Here is something to consider. HST might out pull a gear tractor in certain situations. Let's say we want to skid a big rock. The goal is to not spin the tires so you have maximum force on the rock.

I would think that being able to infinitely adjust power to the wheels in the hands of a skilled operator, would out perform a gear tractor. But what do I know, I have never owned a HST tractor.

You would be wrong, a tractor has max pull WITH a little slippage...

SR

 

[Mat4644]

Depends on the final gearing of the HST. All have gear ranges. One small 2 gear range HST tractor I owned the low range wasn't low enough to apply HST torque properly at very slow wheel speed. Maybe one of the compromises of only 2 gear ranges.

 

[Egon]

There is a difference between ideal slippage for maximum pulling and spinning the tires.

 

[K5lwq]

You would be wrong, a tractor has max pull WITH a little slippage...

SR

I understand "little slippage", what I said was "spin". Big difference. If you can control the power you should be able to maximize the pull. It does not take long until a "little slippage" turns into a "spin" and you are no longer pulling, you are digging.

 

[Mat4644]

I understand "little slippage", what I said was "spin". Big difference. If you can control the power you should be able to maximize the pull. It does not take long until a "little slippage" turns into a "spin" and you are no longer pulling, you are digging.

Just look at professional tractor pullers. You need a level of spinning and digging to get down to the "good ground".