Gear or Hydrostatic Transmissions for Compact Utility Tractors?

[ovrszd]

Wonder why nobody's made a shuttle with HST-like controls? It seems it would not be to terrible to use forward/reverse pedals to actually actuate the shuttle and throttle if linked. You would need some logic involved, but it could make for a potentially interesting option for people who wanted the benefits but the simplicity of a HST.

A very close example would be a hydraulic shuttle with torque converter. They've been used on construction equipment for decades.

 

[SteveM70]

The bolded is the key here. There are such things as immovable objects. Sometimes you just don't have enough gears or horsepower.




I think there are 3 things involved in getting power to the wheels in an efficient manner.

1) engine speed
2) axle gearing
3) volume of hydro fluid getting to the hydro motor

The engine has a natural power curve, the axle gearing is a known entity, but the flow of fluid is infinitely variable. I suspect when engine speeds are low, and gears are high, there is a point where there's just too little fluid flow to effectively drive the hydro motor. A little more pedal, and the fluid flow increases enough to be more effective, but a little too much pedal and too little throttle, leaves the hydro motor wanting for more fluid.

I find that if I'm starting off on a slight hill in high and it seems like it won't pick up properly, I just back off the pedal a bit and throttle up, then I can press the pedal when the speed gets up a bit and cut back the throttle if I want to.

The different pieces can take some getting used to much like any complex machine doing different things under different conditions.

If I read your post right, especially the last sentence, I think we are mostly agreeing.

My point being that there is no golden rule. Easing up on the hydro pedal does not always equal more useful power.

 

[noller9]

absolutely. The Mitsubishi made machine has been flawless, after 150 hours it works just fine. Strong, rugged and capable for it's size. Always starts instantly, even at below zero temps. It's done stuff I wouldn't expect it to have been able to do. The 3 speed axle gives a perfect mix of speed/power.

As to your marshmallow effect..... it sounds like you mashed the pedal down with too little throttle. Remember the further the pedal goes down, the higher the 'gear'. You let off the pedal to get more power to the wheels. The hst is counter intuitive that way.

Based on my experience, I would not spend another few thousand $ to get an equivalent sized Kubota. Especially when the Mahindra will be heavier and have more lift capacity than an equal engine sized Kubota.

Yes I admit I was inexperienced with the HST. I also agree that weight is more important in many operating situations.

I like your Freedom Quote. My 10 year old son already came up with a good one "We have Freedom to follow the rules"

 

[countrybumpkin]

Wonder why nobody's made a shuttle with HST-like controls? It seems it would not be to terrible to use forward/reverse pedals to actually actuate the shuttle and throttle if linked. You would need some logic involved, but it could make for a potentially interesting option for people who wanted the benefits but the simplicity of a HST.

Also the cvt that the caseIH has would be close to that. You have a lever for forward reverse and then one peddle for speed.

 

[4570Man]

The bolded is the key here. There are such things as immovable objects. Sometimes you just don't have enough gears or horsepower. I think there are 3 things involved in getting power to the wheels in an efficient manner. 1) engine speed 2) axle gearing 3) volume of hydro fluid getting to the hydro motor The engine has a natural power curve, the axle gearing is a known entity, but the flow of fluid is infinitely variable. I suspect when engine speeds are low, and gears are high, there is a point where there's just too little fluid flow to effectively drive the hydro motor. A little more pedal, and the fluid flow increases enough to be more effective, but a little too much pedal and too little throttle, leaves the hydro motor wanting for more fluid. I find that if I'm starting off on a slight hill in high and it seems like it won't pick up properly, I just back off the pedal a bit and throttle up, then I can press the pedal when the speed gets up a bit and cut back the throttle if I want to. The different pieces can take some getting used to much like any complex machine doing different things under different conditions.

Every tractor I've ever used with the exception of one had the gears and the HP. They lacked the weight. On a tractor HP usually only determines how fast you go. They usually have enough gears to use all available traction.

 

[Sawyer Rob]

I guess you don't use the pto much, or you would find out that more hp is better, for SOME tools...

SR

 

[4570Man]

I guess you don't use the pto much, or you would find out that more hp is better, for SOME tools... SR

Where did I say anything about that? You must've dreamed that up. More HP is going to be faster in most cases. Just like I stated in my earlier post. Of course that's assuming both engines were truthfully rated to start with.

 

[mcfarmall]

I heard someone on TBN once state, "Weight gets the work done, HP gets it done faster."

 

[Sawyer Rob]

Where did I say anything about that? You must've dreamed that up. More HP is going to be faster in most cases. Just like I stated in my earlier post. Of course that's assuming both engines were truthfully rated to start with.

No, I didn't dream it up... You made the statement "On a tractor HP usually only determines how fast you go"

It just sounded like from reading your earlier post, that you was defending the smaller hp tractors, saying that all of "your" tractors ran out of traction before hp.

My post was simply pointing out that many of us, need extra hp because of the pto tools we use.

SR

 

[jenkinsph]

I guess you don't use the pto much, or you would find out that more hp is better, for SOME tools...

SR

Out of context,^^^^ when you read the post by oldpilgrim that 4570man quoted this was all about tractor response to movement.

I do agree with you on having more horse power for pto work and climbing grades faster etc.