I have tractors with hydros at both ends of the spectrum and each gets used according to its capabilities. The light tractor is used at high throttle settings because it has limited power transmission capability, about 3 hp at the rear wheels. The heavy GT mostly at about 2/3 throttle due to its higher power transmission capabilities, about 11 hp to the rear wheels.
The actual horsepower delivered to the rear tires is directly dependant on 2 factors, the throttle position
and the drive control position. Max power is only available at max throttle and max speed. If either control is reduced, so is available power. My 2400 lb, 16 hp GT typically breaks traction in dirt (compacted or otherwise) at about 5-7 rear wheel horsepower. Higher throttle settings are reserved for higher desired tractor speeds or tractor powered implements. The lighter YT with its less capable hydro needs a higher throttle setting just to deliver adequate power to the ground for the limited work that it can do.
Your Craftsman GT is somewhere in the lower end of that spectrum, above the K46 that is in my Husqvarna YTH 20B42T, and well below the Sundstrand Series 15 that is in my MF1655. You will note the horsepower discrepancy between the engines in those 2 tractors, the light YT with 20 hp and the heavy GT with16 hp. One is designed to deliver hp to its implements (and bragging rights), and the other to deliver power to the ground as well as implements.
Understanding the complicated relationship between engine rpm, drive control (gas pedal or fender mounted lever), and traction capabilities takes time and use to assimilate. For most, WOT and drive control adjustments for the task at hand. Once the relationship is understood, reduced throttle settings can be used to fine tune power to the rear wheels and travel speed.
Precision manoeuvering would be something like clearing the snow away from the side of your new Cadillac with a FEL and dragging a wider back blade behind the tractor at the same time. High speed does not enter the calculations. You want enough power to push and pull the snow while still having time to make steering corrections. Speed in this instance can be measure in very few inches per second. High power settings and a sneeze can result in several thousand dollars in damage... and one really ticked off wife.
Torque is the misunderstood child of tractor power. It is what is required to get a tractor moving so that horsepower can keep it moving. It determines the rate of acceleration, but it requires no motion to be measured. It is measured in a hydro at the maximum pressure that can be obtained for doing work. It is
not there at idle or at full throttle if the tractor is doing
no work.
Take the time to read
this thread from another forum. I spent many hours writing my posts dealing with torque in this thread starting at Post #17.
When I hit these the tractor was sitting there at full throttle, gas fully depress and the wheels were not moving at all. I was concerned that I could ruin the tranny at that point.
Maximum load at maximum throttle with no wheelspin equals heat generation in significant quantity. That is also the maximum torque available... and it's not enough!
Is your hydro designed for heavy work? That depends on your definition of heavy, how much time is involved at that level, and how well it is maintained. Will it exceed the capabilities of a K46? ... Probably. Will it equal a Sundstrand? ... Nope. For that you require a top of the line tractor from JD or some other major player.
Hydros generate heat. The heat generated is consistant with the amount of work done and the time involved in the doing. Pulling trailers is not heavy work. A small group of children can do that. Pushing concrete slabs is heavy work. If the wheels don't spin and the slab doesn't move, it's too heavy for your hydro.
but I hardly ever use the brakes unless I stop on a hill....then it will roll ahead on its own slowly.
