[Scott Kozutsky]

Originally Posted by EricH

Technically, you are correct in the reasons. However, you need to rethink the robot dimensions, specifically the length/width ratio (assuming 34" wide, 40" long).

They're 34" x 40". 1.17 length/width. A typical FRC robot that's difficult to turn has tended to be a 1.35 length/width ratio (28"x38"), and before that a 1.2 ratio. They'll have an easier time than most FRC robots, particularly given that the actual wheelbase will be shorter than 40", probably more like 36" which will give nearly a 1:1. If the ratio of length/width (actually, wheelbase/trackwidth) goes under 1, turning suddenly gets easier without a need for a dropped center. Ask Ether for the physics on how that works sometime, I'm a touch rusty.

There's a reason you rarely see wide-bots using drop-center--it doesn't really help their turning, and it adds to their overall "oops, I fell over again" factor.

Outside dimensions =/= wheelbase. If you're running a west coast drive you've likely got a slightly larger track width and shorter wheelbase than an otherwise equivalent sheet metal drivetrain for example. Other factors like wheel size and center of gravity are major factors in both turning and tippyness, mainly because of how they affect the wheelbase.

From my experience on 1310 (2013), 4wd colsons even in a wide config can cause turning problems. Keep in mind that our high gear was too fast for a 4 cim drive that year but turning was still an issue. (our wheelbase must have ended up at like 2:1 wide but I can't remember the actual dimensions unfortunately)

I have yet to hear a team that used 4wd all traction tank say that they liked how it drove.

Most competitive wide robots I know of used 6wd drop center. 254, 2056 in 2014; 254, 1114, 469, 33 in 2013.