Regarding RPM operating range, I've just always preferred running engines at lower RPM's. It's just psychological as it seems like running higher RPM's is harder on the engine (more friction with more movements within a given period of time), but I understand that is not necessarily the case. It's also just less stressful to hear the engine lugging around that screaming. but, I will operate at whatever the recommended range is, and get used to it. This was something I had a hard time with riding 2 stroke dirt bikes. They really like to be wrung out. I always felt like I was about to melt the engine. Probably both are true!
Geotech, did you decide on a tractor yet? It sounded like you were getting close.
I've been thinking on some of the things that you mentioned as concerns and comparing them with my own experience.
On dealers, I'd feel more comfortable with a dealer who had a good parts inventory and an active, well-equipped service department. How far away he was wouldn't matter if he was within an hour or so driving time. But that's from the perspective of being a guy who likes to fiddle with mechanical things as a hobby. One of the things I like about tractors is working on them, adding things, experimenting with implements....that sort of thing. If I wasn't a mechanical guy I might feel differently about dealerships; just don't know. I might add that I like to support old established small businesses over big corps.... but that's just a personal thing.
So all in all, any advice on dealerships seems like a personal thing.
On 25 vs 35 hp.... That's more mechanical knowledge than opinion. Other than the ability to lift more weight at either end, I feel that both machines will do the same job. It just takes less time with the larger machine and you can run lower RPM doing it.
On operating RPM..... This is a biggie for me because I've always liked to work with a machine at the lower end of the RPM range. It's just how I like to work, other people can differ all they want. The good thing is that with tractors it doesn't make much difference what RPM you start doing a job at because either you naturally advance the throttle as needed, or else the load-sensitive governor does it for you. Every tractor I've ever been on - even the old 195-s 30 HP JD I started with had a decent load sensitive governor and convenient throttle as well. So if you want to set a low base RPM and just advance the throttle as needed to match the load, that works fine. Just don't lug it; lugging it can overheat engine or tranny, but of course that's no different whether it is a car, tractor, or horse.
Just be aware that when a diesel runs at low RPM - especially at idle - it puts more soot in the engine oil. Soot in diesel oil is inevitable and too much is harmful. So extended idle at low RPM means more frequent oil & filter changes are an absolute necessity. And if you pick a tractor with some sort of soot extractor on the exhaust, then extended low RPM is going to make the soot extraction system work harder. So those are the tradeoffs for low RPM work & idle.
I accept the increased maintenance costs of low RPM because running that way also increases how much I enjoy tractoring. The bigger the engine, the better it runs slow.
Tractors don't wear very much. Basically the older the tractor gets, the more I trust it.
rScotty
