BXpanded
Silver Member, Approved Advertiser
Side discharge limits the speed at which the mower can get rid of the grass your feeding it. Having more than twice the opening across the rear means that you can get more in faster achieving the same cut quality and in some cases better with out ever having to hear the engine bog down like we all do from time to time in the thicker grass or on the occasion we let the grass grow for an extra week or two.
So yes your missing something its called volume! Every mower just like a snow blower is limited not just by its overall size or HP but also by the amount of grass or snow it can discharge at a given speed of induction. Simply put why can you lift a guard on a MMM when it tall grass and it will help it get threw it just a little faster? Or why when in tall grass do many folks cut it twice rather than one single cut ? Both answers are simple based on the volume it can handle the side discharge mower cant make the same speed in the deeper grass because its working past its limits and forcing a slow forward advance and in most cases leaving behind a poor cut while doing so because everything is getting backed up inside.
As for the neighboring machines and their perceived abilities you would need to do a much more comprehensive test than just a half hearted side by run without knowing exactly what the operators intent is. My one neighbor appears to cut rather slow in an area that appears to me from a distance to be better than my side of the field but in reality when I drive over there and see all the holes and ruts it is in fact worse and I couldn't cut any faster than he does with any machine Also lets not forget that even zero turns are not all what the name states to us. In fact there are many poor quality zero turns out there with side discharge and limited abilities as well as there are good ones so we would also have to compare the actual machine to other zero turns and add that into you comparison as well as the operator as we all know some folks just are not qualified to run any machine right on down to the shopping cart at the local store so that will also have to be figured into it.
I guess I'm still missing something... The blanket statement was made that mowing time on 3 acres could be reduced significantly, even by more than half, with a Zero Turn Mower as opposed to a Sub-compact tractor. I can mow normal fescue at speeds up to 8.6 mph at full throttle, in high range, with a 60" deck, when the surface is relatively smooth. Evacuating the grass is not a problem and the engine does not bog. Most ZTs I see are also side discharge, and of similar width, so would need a similar amount of power at the same speed. Major manufacturers have been building mower decks for a long time and if there was a truly superior design it would have been thoroughly analyzed by now. The deck doesn't care whether it's carried by a ZT or a tractor.
To cut mowing time by half, the ZT or rear discharge would have to travel twice as fast; i.e. 17.2 mph, or would have to have a 10 foot wide deck, or some combination of larger size and greater speed. I sincerely doubt that a similarly powered mower of either type would be able to cut 10 feet wide or at 17 mph.
I do realize there are big commercial mowers with 72" decks that can go as fast as 15 mph. That could be twice as fast, but that unit is probably a bit extreme for the typical homeowner. Most of us don't have a place (golf course maybe?) that would allow that speed or size.