More is not better with a hydro

btolle · Jan 27, 2005

I was really paying attention to my use of the hydro pedal yesterday while moving a lot dirt up a hill. I still have to overcome the tendency to push harder on the pedal when the RPM's start to drop going up the hill but it works better if I back off a little bit. The RPM's stay up and it easily pulls a hill it would lug on when I had the pedal all the way down.

With the loaded rear tires on the B7510 I could carry a bucket full of wet dirt and pull the box blade till it was overflowing at the same time. As long as I kept the RPM's up it kept moving nicely. If I mashed the pedal harder the RPM's would drop and speed would slow. I could actually bog the engine down to where it nearly died if I kept the pedal to the floor.

These new fangled machines take some getting used to.

Another valuable lesson learned from this forum!

Bill Tolle

PineRidge · Jan 27, 2005

Bill I remember the day they rolled our TC-40D off the delivery truck. Once the dealer had finished giving me instruction and had gone down the road it didn't take me 5 minutes to jump on that puppy and fire it up. I immediately threw it in high range and started up a steep hill on the property. As the RPMs started to decline I stepped on the hydro pedal a little harder until finally the NH just stopped in its own tracks. /forums/images/graemlins/mad.gif I swear I could hear the relief valve singing to me.

Since it was a new tractor and I had no previous experience with hydros I immediately thought that I must have made a huge mistake in purchasing the hydro transmission over the gear transmission.

Once I read the operators manual and realized that with less pressure you get more power I started to get a grasp on the whole hydro concept. I've really enjoyed it ever since.

Just try and take my hydro from me today, it just isn't going to happen without a fight. /forums/images/graemlins/grin.gif

_RaT_ · Jan 28, 2005

Bill, this goes against what everyone has been saying, but I never experienced this. As I recall, right from the get go I was backing off on the pedal. Perhaps it came from the many years of operating a Bobcat skidsteer where the same applies only with your hands. A friend of mine used it and I watched him use it to move a pile of dirt. His first to loads killed the engine, after that he had it down. My brother in law is another story. More pedal means more power right? No matter how many times I tell him, it won't sink in. I'm beginning to wonder if HST is something everyone can learn in one sitting?

BrettW · Jan 28, 2005

now I know, don't know if I thought about it or not before. I just add more rpms if it is bogging down, bw

PineRidge · Jan 28, 2005

now I know, don't know if I thought about it or not before. I just add more rpms if it is bogging down, bw 

It's a little like flying a fixed wing plane. Yes you can increase engine RPMs for more airspeed or simply drop the nose and the speed will come up quickly automatically. With the hydro you can also increase RPM's but it's easier to just come back on the pedal pressure a bit and the RPM's will take care of themselves.

theboman · Jan 28, 2005

That's mistake number 1 and I'd bet 90% or more of hydro owners have done the exact same thing by usind the hydro pedal as a "gas" (diesel) pedal.

It's all about applying torque to the ground where less (pedal) means more (torque to the ground).

radair · Jan 28, 2005

Cool, you really do learn something every day.

Now, whether I remember it or not is another issue.

MadDog · Jan 28, 2005

Pineridge: The analogy is even better with a constant speed prop. There, adding power (throttle) increases the pitch of the propeller and thus increases thrust. You can then translate the increased thrust, depending upon nose attitude, into increased airspeed, or climb, or some combination of the two. The variable pitch Prop is sort of the equivilent of the continuous hydro tranny.

The difference is that with a hydro tractor, you set your rpm and then, for that rpm level, you can infinitely vary the apportionment of that level of engine output between speed and work power for that setting. The hydro pedal, as I understand it, increases the gear ratio and thus the speed of the driving wheels the more you depress it. The trade-off is that the more speed you call for, the less working power you have.

BTW, what do you fly? I used to have a Mooney M-21 (4 seat, retractable gear) and before that, a Cessna Skyhawk.

Someday, perhaps I'll get another. /forums/images/graemlins/grin.gif

CurtC · Jan 28, 2005

( Bill, this goes against what everyone has been saying, but I never experienced this. As I recall, right from the get go I was backing off on the pedal. Perhaps it came from the many years of operating a Bobcat skidsteer where the same applies only with your hands.)

Absolutely, the same concept on skid steers, the brain is ready for it. Those who may have just driven cars, bikes, where the basic rule is 'when in doubt, gas it', it's more natural to treat the hydro pedal like a gas pedal. Takes a bit to unlearn that.

PineRidge · Jan 28, 2005

BTW, what do you fly? I used to have a Mooney M-21 (4 seat, retractable gear) and before that, a Cessna Skyhawk.


MadDog I trained in a Cessna 150, and flew weekends in a Cessna 172. I tried to outrun a nasty thunderstorm one hot summer day years ago and didn't make it. I actually ended up taking a real wild ride through it and at that point I came to the conclusion that: I would much rather be on the ground wishing I was in the air, then in the air wishing I was on the ground. /forums/images/graemlins/shocked.gif

I have not flown since, I'm grounded......