According to this page
The Coyote Quad is an incredibly powerful, long range electric ATV that you can fit in the back of an SUV. It's stealthy and perfect for hunting, and also for running about the farm without the fuss and noise of gas.
outriderusa.com
They have different drive systems depending on what a customer chooses, one a middrive and one is hubmotors (possibly the GMAC) in the wheels.
this section is a single motor thru a gearbox
RWD Live (solid) Axle - Our lightest drive system, ideal for sport use
Mid-drive utilizes proven Outrider carbon belt-driven electric drivetrain technology, paired with state of the art planetary gearbox for improved performance, durability and capability.
A premium American made motor that is mated to a premium German gearbox. This combo makes for the ultimate in performance.
Up to 3000 watts max motor output with RWD
Optional pedals
Top speed of 22 mph
The RWD live axle is a great configuration for heavier riders up to 400 lbs
.
and this is two or four hubmotors in the wheels
2WD or 4WD with Independent Suspension - Our most capable and quiet off-road drive system
Highly efficient in-wheel motors bypass the necessity of a belt drive entirely. Instant torque, straight to the wheels.
In-wheel motors also make for an extremely reliable redundant drive system
Low-noise motors are virtually silent, a great fit for sound-sensitive applications
5000 watts max motor output with 4WD (requires 3024 watt-hour or larger battery pack for 5000 watt output, max output of 3000 watts with smallest battery option)
Top speed of 22 mph
The German planetary gearbox is probably a Neugart. They make a lot of different kinds, and they've been used in various middrives even here on ES. Just not cheap.
Neugart USA Corp. is a gearbox manufacturer in North Carolina. Neugart USA stands out in North America and stays true to its German engineering quality.
www.neugart.com
I don't know which one you need, but that can be figured out.
The only "premium American made" motor I know of is Astroflight, if that's not it maybe someone else can chime in with possibilities. Any motor that will fit in your available space, and can make the power you need and be connected to a gearbox to reduce it's speed to provide torque instead would work, though.
What speed do you get on the flats from your present system?
What size wheels do you have, and what is your present gearing from motor to axle?
For your present drive system, is there anything other than just a sprocket bolted/welded to the live axle, receiving the chain from the motor?
If not, then there are several options, including some that keep everything else you have (assuming they can provide the power needed).
You could replace the present live axle with one that has a built in transmission/gearbox, that gears down your present motor's speed for more torque. If you need more speed when not climbing (the speed you have now) you could use a gearbox that has shiftable gears, one of htem being 1:1, and keep your present motor-axle gearing. (or some other ratio that gives you the same speed you have now). It'll still going to be slower in climbing by whatever ratio you need to get the torque to climb with (unless you can use a higher voltage battery to spin your present motor faster; this may also require a higher voltage controller). Actual speeds all depend on what you've already got.
You may have to change the controller, gearing, battery, motor, to do it, depending on what your system parts already are capable of.
You could start over, and do what they did, use a high RPM smaller motor (like the RC motors by Astroflight and many other companies) driving a high-ratio reduction (like a neugart) to the existing live-axle.
You could use one of the motorcycle motor/gearboxes like those QSmotor makes, then gear it down further for more torque and less speed.
A quick slapped-together simulation
Our ebike motor simulator allows you to easily simulate the different performance characteristics of different ebike setups - with a wide selection of hub motors modeled, and the ability to add custom batteries and controllers and set a wide variety of vehicle parameters you'll be able to see...
ebikes.ca
shows 4.2mph under your stated conditions should take around 2kw from a 52v battery. With the default gearing it only makes 637W at the motor so most of that power is wasted, different gearing with a higher voltage battery (or faster wind motor) would probably help with that, I didn't play with the gearing/etc to find out what would be optimal; I only set up the simulation to find out about how much power it would take to do what you want (roughly 2kw, probably having at least 2500w-3kw on tap from battery, motor, and controller would be a good idea).
For your existing 1kw DD hubmotor, if that 1kw is a nominal all-day-every-day rating without getting hot, then it may well be able to do double that if it can be kept at a high enough RPM (low enough gearing from it to the axle), and kept cool (there are various ways to cool DD hubmotors, depending on environmental conditions).
There are other options not covered above, and other people may have other ideas, too. What you can actually do depends on what you've already got and what you can change.
