Wheel motors on - starting to get anxious now...

[ponytug]

Dear KentT,

Thanks! I will check them out. It isn't very often that you see a US company offering its website in Swedish and Finnish. (But that seems like a strong endorsement to me!)

All the best,

Peter

Don't know if they have the right size for you, but here's a good resource:

Welcome to Wallingford's Inc. - Logging Supplies and Tire Chains

 

[SpringHollow]

One of the big advantages of the diamond pattern is that it keeps the chain above the bar tread. Otherwise, your chain has to be taller than the depth of the tread (such as double ring chains).

ken

 

[Homebrew]

I do make sure to NEVER lug the engine though, when operating at less than full throttle.

Okay...I'm new to tractors and I'm sure this is a stupid question, so laugh away! But, what does "lug the engine" mean? And, is it okay to lug the engine at full throttle?

 

[KentT]

"Lugging" an engine means to load it down to the point that the engine slows down or struggles to meet the demands you're placing on it -- it can't maintain its RPM against that load. Typically with an air-cooled engine, there's two steps that occur when you place a large load on an engine (at virtually any RPM).

First, most small engines have governors on them that limit the top end RPM but also interact with the carb automatically to try to maintain the set speeds. If a larger than intended load is placed on the engine it will kick in the governor, increasing the flow of gas/air to the engine trying to maintain the RPM you have set with the throttle. If that isn't sufficient, the engine will then slow down because it can't produce the demanded power to meet the load. Each of those steps typically will sound a little different to an experienced ear. The governor kicking in will often be more of a "deeper sounding roar." The engine slowing down is also a low, deeper sound, and will sometimes result in a "struggling or chugging" sound if you don't remove the load being placed on it, or give it more throttle (if you can). You can lug an engine until it completely dies -- NOT a good thing.

Running on governor will cause an engine to run hotter if it occurs for an extended period of time. Though it technically isn't the same at all -- imagine an automatic transmission in your car downshifting to "passing gear" and then trying to run there for a long time to maintain the same speed. The car's engine can also overheat in that circumstance. In both cases (small engine or car engine) the engine is creating more heat working than the cooling system at that speed/RPM can handle.

Once you get used to the sound of the engine at different throttle settings, you can hear these changes occurring. With the PT you'll often also hear hydraulic noises as the hydraulic motors strain to meet the demands...

In summary, it's never OK to overload the engine for extended periods, regardless of throttle setting. Small air-cooled engines are perhaps more vulnerable than water-cooled engines, but it's not good for the longevity of either one...

EDIT: Just for grins, I googled "lugging engine" and found this description from Tom & Ray, in regards to a car engine -- in this case, trying to take off at too low RPM or in too high a gear...

Tom And Ray Explain 'Lugging the Engine' | HamptonRoads.com | PilotOnline.com

 

[Homebrew]

KentT,
Thanks for the detailed explanation...always nice to learn a little something.

 

[Gravy]

Kent,

That is one of the best explanations of lugging that I have seen. I've known what it is for decades, but I've never explained it that well. Great job!

Gravy

 

[KentT]

I just returned from TN, and wanted to report on my initial impressions of the new wheel motors. I won't use hyperbole, but just say that the only limitation this PT-425 has now is traction, and that is with four loaded bar (ag-type) tires... it will climb anywhere that I'd even consider taking it.

Here's a few pics of the motors installed. They're about the same length of the original White RS motors, but their diameter is about 3/8" more than the width of the rectangular White motors. You can see the trimming of the openings in the tub to get them in. The flat braces on the bottom of the wheel motor box on this older model (December 2000) 425 didn't interfere with the motors at all. Similarly, they clear the spring-loaded parking brake just fine...

 

[MossRoad]

So you now have a mountain goat?

 

[KentT]

So you now have a mountain goat?

Pretty much -- I didn't get any action shots. But, I could take it anywhere I wanted to go on my property. Above the driveway, where the PT struggled to climb the slopes at an angle in the previous videos, I mowed going straight up the hill with no problems. I even sat on that that slope and dug large holes to plant fruit trees (see the 1st pic below), then hauled topsoil to fill the holes and finally mulch to spread around them. The PT wouldn't sit on that slope with the parking brake -- the front wheels would slide down (see the skid marks!) -- but the wheel motors would hold it up there so I could work.

On the steepest area down front near the trees, it wouldn't climb the slope without spinning when pushing the brush-cutter, so I'd climb straight up it with the mower lifted, then mow while backing down it. I used the same technique to mow the bank below my driveway -- I cut the use of the string-trimmer down dramatically!

 

[RegL]

Do you notice a lot of difference in speed.