Product Idea

RC Roadster And Racer 2in1

- Full custom large modular development platform featuring XL MAXX twin shock long travel suspension and all new high moment steering system 
- Full remote control functionality with 7 speed forward and reverse drive and precise 15 position steering 
- Made for your large Lego figures to travel in comfort and style 

These models incorporate an L motor, a servo motor, a battery box, IR receiver and speed remote control from the Lego Power Functions range. 

The front and rear axle assemblies can be treated as independent elements, so you can build your own custom body without stripping down the entire model and beginning from scratch.   They can be joined to create a 6 or 8 wheeler.

The Roadster features two seats scaled to comfortably fit Lego buildable figures.  I used 75144 First Order Stormtrooper (and the slightly larger Stormtrooper) to design the seats and cabin and there is a fair sized opening boot/storage area at the back.
The motor outputs directly into the rear axle differential. 
The battery box is incorporated into the structure between the footwells with openings above on each side to allow battery changes.
The servo motor operates the steering via a reduction gear and twin shafts.

The Racer is single seat with the battery box removable from a compartment behind the driver.  The motor drives a differential via the visible gears at the back, which allow faster acceleration.

The Roadster has adequate driving performance: The Racer is quicker and nimbler, due to the motor gearing, short overhangs front rear and sides, and overall lower weight.   

The standard wheel hub with incorporated ball joints does not allow the servo motor to overcome the tyre friction adequately, so I have extended the standard control arms by one hole and used the newer wheel hub to extend the steering arm out and increase the moment acting on the wheel. The rack has been augmented with a beam on each side to allow extra restraint above to prevent lifting.