Hydro or Shuttle for the long haul?

[the old grind]

Get over thinking high range is for anything but traveling unloaded on level ground! What other vehicle tows in top gear?? Does one trailer their tractor in top gear because low doesn't go fast enough? HST is literally a hand shift because one range doesn't suit all tasks. That's why there are typically three. If you have and compare a 2-range you'd have more to compare to. (a 26hp bowser, my GX26 is for that)

My 35hp won't go up a commonly traveled hill any better than my 23hp did. (Same tractor, different engine.) The hp 'loss' of HST is in the limit of the hydro motor not input power to it. Higher rpm or hp won't help if the HST stalls and goes into relief for being in the wrong range. Full flow to HST doesn't require max rpm or hp any more than hydro flow and pressure does.

Oh, the learning curve with HST. ... More hp suits the PTO better than the HST drive. Learn your limits of both or wonder until you catch on.

 

[rbstern]

Get over thinking high range is for anything but traveling unloaded on level ground! What other vehicle tows in top gear??

You're mixing metaphors. Some of us go uphill while just travelling, not necessarily towing. I'm speaking from a shuttle perspective, but the issue is largely the same. In my case, my high range has limited use (1st gear) when I have the backhoe mounted and going uphill. Is that towing? I suppose it could be, but if my tires were loaded with the same weight and I wasn't carrying the backhoe, is that towing?

It's not a static scenario or calculation. One might hit the hydro pump output limit before HP runs out. Or not. Not every machine will be the same, not every scenario will play out the same. I strongly suspect, on 25hp compact sized tractors like the ones we're talking about, there's more hydro pump capability than there is HP.

 

[Blue Mule]

Yeah maybe I did a poor job of explaining, but I'm NOT trying to work the tractor in high. What I'm saying is that high is useless. I can't even DRIVE the tractor in high if it encounters any hill or incline at all.

The TC29 that we traded in was a gear drive tractor, and in high range I could drive it in 1st or 2nd pretty easily but 3rd would start to show the strain. Granted, it was 5 more horsepower and gear drive. But it doesn't seem like this new tractor can be operated at the same apples to apples gearing at all. This one likes high RPM and lower gears.

I was REALLY wanting to avoid DPF and EGR on my engine, but it is starting to sound to me like I need to go back to the dealership and test some 35 and 40 HP units and see what I think. This 25 HP unit would do anything I want, but SLOWLY. I don't always want to creep around.

 

[RickB]

That's because it's not apples to apples. You've got 4.6 less hp, a much less efficient transmission and only about 80 lbs less base tractor weight. Probably putting 10 less hp to the ground. That's a huge percentage.

 

[the old grind]

... I'm speaking from a shuttle perspective ... One might hit the hydro pump output limit before HP runs out. Or not. Not every machine will be the same, not every scenario will play out the same. I strongly suspect, on 25hp compact sized tractors like the ones we're talking about, there's more hydro pump capability than there is HP.

It's not the hydro pump that limits grunt in any gear it's the drive motor's limit, not the engine's. That's when/why we go into bypass and the drive stalls. More hp with the same HST drive won't provide more power to the wheels. Bypass is bypass, so the hydro motor stalls when we ask too much of it. (15 years with the 23 hp 1520, and 5 with the same size 35 hp T1520) It takes a bigger frame size and entirely different HST drive to put out any more torque from its bigger drive motor.

btw, my 35 will also stall/bypass when empty on my hill in med at full pedal. I have to back off the HST to avoid going into bypass and stalling forward motion.

OP, I urge you to go up in o'all size vs just in HP lest you gain nothing in pulling power or when climbing grades. That's what I've learned from three of the same HST drives in 23, 33, and 35hp NH CUTs.

That's because it's not apples to apples. You've got 4.6 less hp, a much less efficient transmission and only about 80 lbs less base tractor weight. Probably putting 10 less hp to the ground. That's a huge percentage.

Ayup. :thumbsup:

 

[uphere]

My own experience is limited with HST (last 3 years) but I can give you my own observation - last 10 years I have had two 40hp tractors (same make) one with a std transmission and one with a HST. One was a little larger (the loader was a little stouter) but had no cab - the other had a cab (the HST) and a slightly smaller loader. Overall about the same weight. The open station had a 4cyl - the cab is a 3cyl but a turbo. Same size snow bank I can push across the field with the HST (1st gear at 2000rpm) and hardly have it grunt - it seems to have more torque. The std. trans will also move the pile there but complain more while doing it (I would need to increase the rpms quite a bit to get the same result).
Not a scientific test by any means - just what I've noticed ... and before someone asks - both in 4X4 and same R4 unloaded tires

 

[Xfaxman]

Yeah maybe I did a poor job of explaining, but I'm NOT trying to work the tractor in high. What I'm saying is that high is useless. I can't even DRIVE the tractor in high if it encounters any hill or incline at all.

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Many years ago that same thing happened with a machine I bought. It was a two range HST. When it came to a hill in high range the engine rpm would stay the same, but forward movement would stop. Shift to low and it would go over the hill.

The dealer said the pressure relief was set too low for high range.

 

[Blue Mule]

Just to appease my curiosity, I think that on Saturday I'm going back to my dealer to test a 40 HP HST tractor that they had sitting right next to mine the day I bought it. This dealer actually has a couple acres of land across the street that happens to be on a hillside. They park the large ag tractors over there. I'm going to see if they'll let me drive a 40 HP Compact tractor with HST just like mine over on that hill. That will reveal for certain what the difference would be and then I'll know whether I should trade up or just learn to use what I have. Should be interesting.

 

[RickB]

Please share your observations.

 

[the old grind]

Apples to oranges if the 40hp is a different o'all size and has a different HST drive motor within. Be sure to compare that & not just the hp difference.

Another 12 hp didn't help me at all when trading up to same size/wt & a more powerful engine but with the same HST and the limits of its drive motor.

Can't wait to hear what you learn.