The Traxxas has a very short wheelbase and a chassis layout which places some of the heaviest components high above the centerline, creating a high center of gravity. Together these attributes make for some very sketchy handling dynamics as well as significant compromises in the body designs I can create.
I started designs for extended rear suspension arms to stretch the wheelbase, but found that when working with the existing mounting points, driveshafts and pushrods there is a limited range in how far the arms can extend. Further, the longer arms wouldn't help address the layout of the motor, ESC, and radio which gives the chassis a high COG. An entirely new chassis design is much more involved, but would allow far more radical low-center-of-gravity component layout modifications and a means to stretch the wheelbase without suspension component compromises. The potentially more compact component layout would also enable more options in body designs.
A new upper deck mounts across the tops of the existing bulkhead and suspension assemblies. A cut-out in the deck allows the VXL motor and transmission unit to be rotated 76 degrees to the right and down around the output shaft location. The motor is so low in the chassis now that it is effectively underneath its original position, a significant drop for easily the heaviest component on the car.
Running lengthwise from bulkhead to bulkhead underneath the deck is a longitudinal beam with a trapezoidal cross section (much like a freeway overpass or bridge structure). This beam stiffens the deck from front to rear, and has an outrigger structure to support the motor and transmission cutout.
Only the steering servo is kept in its original position, mounted to the upper deck. The battery and radio will be hung underneath, and the ESC is centered above, along side the motor. Despite all the changes, the only permanent Traxxas component modification will be to lengthen the rear center driveshaft.
The design is kept relatively simple so I could produce it by hand from flat aluminum sheet. The deck and beam can be produced at varied lengths as well; currently I'm working with a modest 21mm increase (to 230mm) and could easily do a version at a prototype-scale 245mm or even the 1/10-scale touring car standard 257mm.
The layout of the components is now much more compact and much lower than on the original chassis, and the wheelbase is effectively adjustable. This will enable an excellent platform for much slimmer and much less compromised bodywork designs.