From a power transmission standpoint, Electric Adventure Vehicles (EAV’s) pose an interesting design
problem. On the one hand, they require transmission components that are not too heavy or bulky. On the
other, they need lots of torque or they won’t be much fun to drive. Outrider USA, which makes a line of highperformance EAV’s, has solved this torque density problem with the help of an economical planetary
gearbox from Neugart.
Founded in 2009, Outrider makes two basic models of high performance EAV’s: the Alpha, built for everyday
use on gravel and streets, and the Horizon, for riders who partake in off-road cycling. Both models have four
variants, each with a variety of design features for ablebodied and disabled riders alike. These configurations include: off-road handcycles, foot pedals, rising seats and adaptive tri-pin hand controls. Each model can be
outfitted with 1 to 4 Kwh.
For high speed road applications, Outrider uses the single-stage version of the Neugart PLQE 60-mm
gearbox, which has a 5:1 gear ratio. In applications where lower speeds are needed, they use Neugart’s
two-stage version with a 15:1 gear ratio. Both gearboxes have identical mounting configurations,
the only difference being that the two-stage is slightly longer.
“It’s a nice, simple system that directly couples with the planetary transmission and transmission drive,”
said Outrider co-founder and technical support Tommy Ausherman. “With the PLQE 60 gearbox, there’s no
need for any other gearboxes or extra parts.”
Designing for torque density.
Outrider engineers initially struggled to find transmission components that met their high
performance standards, packaging requirements, light weight and cost targets. They considered several
options, including a two-stage belt drive. However, this option didn’t provide the necessary reduction for all of
Outrider’s different models. Had they gone down this route, they would have needed a three-stage belt drive
that would have taken up almost three times the space of the PLQE planetary gearbox.
One of the biggest challenges Outrider faced was finding a gearbox with enough torque density to
handle up to 13,000 RPMs. Since EAV’s use a high performance motor, the gearbox they selected had
to meet both their RPM requirements and desired output torque. Most smaller gearboxes can handle the
RPM requirements, but offer less torque than Outrider needed for their application. With up to six planets,
Neugart’s PLQE 60 can achieve a higher torque density in a given frame size than gearboxes with fewer planets.
Outrider engineers also took advantage of the ability to overload the gearbox, cranking up the speeds and
torque. Neugart gearboxes in this size have a regular torque rating of 40 Nm. Even when overloaded, the
gearboxes maintain consistent high performance.
Since the PLQE 60 gearbox weighs only about two pounds, it helps keep the drive system weight low at
roughly seven total pounds. Outrider’s power-dense drive system puts out about five and a half horsepower
out of a seven pound package—almost a pound per horsepower. It’s also maintenance-free and highly
durable, thanks to the Teflon-sealed, lube-for-life bearings in the motor.
Traditional electric trikes have a power output of 750 watts. Outrider’s have anywhere from 1000 to 5200
watts, depending on how they’re set up. These vehicles stay charged for up to 180 miles, with speeds topping
out at 50 mph.
For most gearboxes, you need an adaptor for connecting the motor and gearbox. This adds extra
costs, weight and dimensions to the system. However, the PLQE 60 comes with Neugart’s direct motor
attachment (DMA) for easy, direct mating to the EAV’s motor. This integrated, space-saving design reduces
weight and costs, and cuts down on size.
The PLQE 60 also comes with an attached flange for easier mounting and rigidity, creating a stiff connection
for the drive system.