dumb question about HST

[LouNY]

I had another question about HST vs gear, and it hit me to ask Google's AI, since it knows everything:

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(text above was highlighted by Google, with more info on each of the four items offered below the above text)

After I read the above, I was thinking that HST is best for lower power applications, but I remembered that I've rented articulated wheel loaders before. They were larger than a utility tractor, and they are HST?!?

I guess that the word "loader" in articulated wheel loader is key. A wheel loader is more focused on a single task than a utility tractor, and that task is 99% back and forth, stop, start, reverse, etc, and that is the area where HST excels.

I haven't run a front end loaded in close to 20 years, at that time they were mostly and especially in the larger ones, gear drive with torque converters and reversers.

 

[JTKub]

Now that you mention it, I do remember seeing something, somewhere, about a hi/lo within ranges. Sounds pretty nice.

Most of my reading/looking has been on Branson/TYM tractors. Guessing those do not offer this or I would have read more about it...?

The TYM T224 I bought has a high/low range to the HST. Just like you say, the manual says to come to a stop before switching from one to the other. Some of the fancier deluxe models have 3 ranges to the HST.

 

[Gem99ultra]

One concern you may have regarding an HST vs Geared is having to use the pedal contantly for mowing, etc.. I'll point out, my HST has a 'cruise' lever, so that feature is a no-issue.
Regarding the power loss, I don't think I've ever ran into a problem with the power margin being so close to may me decide on HST vs Geared. The convenience of an HST far out paces Geared, of which I've owned two of in the past.

 

[phantom309]

yeah, I think a lot of CUT work is perfect for HST and HST is perfect for it, while utility tractors tend to be more in the.... tractor.... application, where HST can be a negative and there's little point of having it.

I think you've nailed it. Both have pros/cons. What is best depends on the application.

As others have posted, the best plan is to have one of each!

 

[hayden]

Check some videos about how the Fendt Vario transmission works. The i-HMT is a scaled down version of it.

Yes, the hydrostatic pump and motor will lockup by angling the swash plates in a way those are technically working against each other. This causes the the power to be transferred through a planetary gear and the tractor is then mechanically driven at higher speeds where the typical HST would fall on its face.

The i-HMT is actually different from an IVT/CVT. In particular, it doesn't utilize a planetary gear, but instead has a combined hydraulic pump and motor where both the body and the shaft rotate. It takes a while to get your head around how it works, but it's pretty cool, and definitely unique. It will be really interesting to see how they work over time. HST is very well proven, as are CVT/IVT transmissions, but the i-HMT I believe is all new.