Ol' Duffer wrote:

In article ,
says...


Been reading everyones posts about the driving tractor mowers. We are
building a house in the country with a huge front lawn(not our idea, it's
required by the community), and we are trying to decide how to handle it
(lawn service or mower) After reading some posts regarding these things
having "automatic transmissions" and how they make the job easier, I am
curious..I am sure they don't have transmission like a car which shifts
gears and such, but was wondering how they work? Can you slow down, stop
and go without having to disengage the gears and such? My guess is a
standard one with a clutch you would be clutching and going to get around
flowerbeds and such...Seems the auto is the way to go if your gonna have
one..But just curious as to how they actually work...



The clutch and gear transmission type are not as bad as
you might think. Yes you have to stop, shift, back up
and turn, stop, shift, etc. You get used to it after
awhile if the ergonomics aren't too bad. You need the
durability of gears if you are going to be pulling heavy
stuff around regularly, but the "automatics" are nice
if you are going to use it just for mowing or maybe drag
a little utility cart around.


Really? My 10 year old automatic tractor can drag a big homemade dump
cart around, like a 4' W by 5' L with 1' H sides, and golf cart wheels,
carrying dirt filled to the top of the rails. I have a ball hitch
installed on the back of my tractor to pull the cart. The only problem
towing it up some grades when full is that the drive wheels sometimes
skid on the grass. My set of wheel chains helps in those instances.
Also, I have a 48" snow blower attachment that weighs a couple of
hundred pounds and requires that I weigh down the back of the tractor
with wheel weights and a US Military GI can, filled with water, strapped
to the back of the tractor. My driveway is sloped and I have no problem
snowblowing while driving uphill.
Did I mention that the tractor was 10 years old?

I don't entirely like the term "automatic" as applied
here. I guess it's a sales thing, and who can understand
the murky workings of their minds ;-)

The best, IMO, is hydrostatic. These use a variable
displacement hydraulic pump driven by the engine and
a hydraulic motor geared to the wheels. The pump
displacement control usually connects to a single
lever or pedal which gives you continuous range from
forward thru stop thru reverse. Usually so reliable
you could just drive it for years with no attention
at all, although transmission fluid and maybe a filter
should be freshened up at relatively long service
intervals, and are easy to do.


My auto transmission does not have to be refreshed with fluid and there
is no filter.

Some of the cheapos use another approach with variable
width v-belt pulleys to get adjustable drive speed.
These work well enough new, but get "funny" with age
as the belts wear valleys in the pulley faces. Most
implementations have an in-line "shifter" with notches.
It is also possible with two belts or with a belt and
gear combination to get a single pedal or lever with
continuous range from forward to reverse, but that's
more engineering and most of them don't bother since
they are designing for low price. The belts wear out
and have to be replaced, and are usually not very easy
to do. Some even call it a hydra-something-or-other
drive to make you think you are getting a hydrostat,
when in reality it is something else not nearly as good.

Caveat emptor, you get what you pay for, etc.