Originally Posted By: Nayov
What was the reasoning behind the odd ball wheel configuration on those things and what's the vestigial wheel up front for?
The fifth wheel up front is to prevent the right front from nose-diving into a root or depression in the ground. The staggered-wheel design is one that prevents scalping of the grass and allows a remarkably flat cut on uneven ground, but there are drawbacks as well. That right front is like a big scoop...if you have the mower set low (as many southern grasses prefer), it's not hard to "dig" that right front into the ground, especially if it's not self-propelled, as that mower in the picture appears not to be. When you push on the handle, the front of the mower will naturally want to lean down.
This isn't really a problem on self-propelled mowers. Pull the bail and the rear wheels spin and weight is actually lifted OFF the front. But when pushing, that front wants to dig in. It's also not really a problem with the alloy decks. Compared to the alloy decks, the steel decks flex a lot. I own two of both and won't buy any more steel deck ones.
Same concept as the deck wheels on a riding mower. I actually like that guy's idea (the fifth wheel).