Does engine HP affect driving power

[sportscarclinic]

I used to have a 45 HP manual **** tractor. I have a 66" snowblower that goes in the back but you drive forward with it. When I got into heavy snow I would have to downshift the tractor to the next lower gear. Three years ago I sold that tractor and bought a Kioti 35HP HST tractor. Now when I get into heavy snow I simply back off the peddle a little and it will go right through it even with 10 HP less than the old tractor.

So you're saying that with your manual transmission tractor, you'd actually have to manually change the gears (downshift in this case) when the traction or load conditions changed?

 

[Larry Caldwell]

The HST pump is a wobble plate that drives a conventional hydraulic motor. The more you push on the HST pedal the wider the wobble plate opens, so it really is a variable pump. It's pretty durable, but to minimize stress on the hydraulic system you want to run pedal down. That moves the maximum fluid through the cooler. If you look at the manual, it tells you not to run in high range until the fluid has warmed up. The HST system sucks about 5 hp no matter how big the tractor is, so a 25 hp tractor will only have 20 hp to work with, while a 45 hp tractor will have 40 hp to work with. It will do twice as much work, whatever you are doing.

The tradeoff is purchase price and fuel, vs. time. If you don't care how long a job takes, a smaller tractor is less expensive and will get you there, but it will take a while. There are some jobs that bigger is essential, like lifting and placing large riprap. You aren't going to pick up a 4' boulder with a 35 hp tractor. For pushing and pulling, or climbing hills, ag tires are far superior, but they will tear up a lawn, so tire selection will depend where you run the tractor. Ag tires also scrub on pavement and will wear out faster on hard surfaces. Turf tires are the other extreme. They are kind to grass, but spin out if you try to push the bucket into a rock pile of brush. Industrial tires split the difference, and are good for running on rock, quarries, etc. without doing too much damage to turf. I prefer ag tires, and if I have to run on a lawn I wait for dry weather.

 

[tree grower]

This has been a great thread, and confirms my preference for gear drive over hydro in any vehicle (if possible). I use my 1996 Toro 522 for mowing between rows of Christmas trees. Last summer for the first time it could not climb a 20% grade at max rpm in high range with mower engaged. I don't need to mow fast, and down-shifting permitted continued operation, but the change over previous years has me concerned. The dealer could find nothing wrong, but recommended changing from 10-30 oil to 15-50 synthetic. Will see what happens this summer.

 

[Egon]

Some information on HST as used on larger Equipment.

Hydrostatic Transmissions Provide Smooth Operations

Hydrostatic transmissions, or HST, have been available in the construction marketplace for quite a while on crawler dozers with similar designs on excavators. But it’s only within...

www.constructionequipment.com

 

[Cranblue]

Some information on HST as used on larger Equipment.

Hydrostatic Transmissions Provide Smooth Operations

Hydrostatic transmissions, or HST, have been available in the construction marketplace for quite a while on crawler dozers with similar designs on excavators. But it’s only within...

www.constructionequipment.com

Ran a WA 200 komatsu loader awesome machine dam near bullet proof !!

 

[Bullwinkle123]

Wow, a lot of dissing the HST, which is fine. Here's my two cents.

I bought an MX5400HST. I bought HST because (a) it sounded a lot better for noobs, both me and my wife, and (b) it sounded a lot more convenient for loader work.

I use it on a very steep hills. There are basically two (of my own) rules I have developed for going up steep hills:

1. Be in 4WD.
2. Be in low gear.

Again, this applies to steep hills, or moderate hills under load (say, a bucket full of rocks pulled out of those hills). I have never had something I couldn't traverse in low gear with load. (Also: cue the Messicks video about use of the HST throttle w.r.t. gearing, sorry, don't have a link).

I have no issues with the tractor at all when I follow those rules.

That doesn't mean I never use higher gears, normally I'm in medium gear for most everything unless the hill is steep or the load is high. Even then, a bucket full of gravel is fine in medium just moving it along the driveway.

The only time I've ever wished I had more power is when lifting with the loader, mostly when I'm trying to get rocks out of the ground, or bust up a pile of dirt/rocks that has settled.

Love the convenience. Love the precise control, especially on those high-pucker-factor hills where I want to go v_e_r_y s_l_o_w_l_y.

I've read things here about how HST is probably better for stump grinding uses, where you need to move slowly, but can't speak from experience.

Anyway, not saying it's better or worse, but it's working for me. Would I have been equally happy with gears, maybe, don't know. Other geared vehicles/motors are fine, but I'm not unhappy I spent extra on the HST tractor. The control is great, and there's a lot less to explain if I want to convince my wife to try it (though I haven't done that). Using it is dead simple.

 

[art]

Weight to horsepower is always critical! To many people are making their tractors to fat for the occasional need and sacrificing daily performance! Some times it can be overcome just by having more gears or ranges. I like the three range hydro's!!!! Best ever!

 

[CobyRupert]

I can’t help but wonder what percentage of owner treat the hydro pedal like a gas pedal. When they get to a hill and the tractor starts to slow down, they just mash the pedal down further?
Think it’s greater or less than 50%?

 

[hube2]

I can’t help but wonder what percentage of owner treat the hydro pedal like a gas pedal. When they get to a hill and the tractor starts to slow down, they just mash the pedal down further?
Think it’s greater or less than 50%?

Is this a poll? My vote is greater than 50%.

I can tell you that when I got my first HST this is what I thought and this is what I did for at least 2 years, maybe more, until I did some reading and figured it out. This is also what my FIL is doing with the old lawn tractor I gave him and even after explaining it to him several time he still thinks of the pedal as a "go faster" pedal.

Once you figure it out you find that you can actually go up hills faster if you let up on the pedal so that you're in the right "gear".

 

[rScotty]

Or drop down a gear.