The spread is 3.64. It is for a sheet metal, non WCD chassis. I considered putting the motors over the wheels, but I decided that the CG benefits of lowering 17 pounds around 4 inches would be more beneficial. My weight estimate only says 10.999 lbs, but I was comparing it to the 12.94 value from
http://www.wcproducts.net/wcp-shifter-3cim/ (Standard, non-WCD, with 3 14t motor pinions, motors and 1 pneumatic cylinder). I think mine has one or two fewer gears and is thinner, but .2 lbs can probably account for that. I wonder how they got 12.94 lbs?