Bicycle Frame Tech


An entirely new class of two wheel vehicle has burst on the scene over the last few years, with design cues taken from the sketchpads where superheros are born. Like the action heroes that have a mild side, most of these bikes can switch personalities on demand, from road legal urbanites to high power offroaders. But are these brawny but lean rock-hoppers souped up BMX bikes or stripped down off-road motorcycles? The nearly silent, high power afforded by digitally controlled electric motors and lithium batteries has enabled an in-between class of vehicle that is far more than a mountain bike, but not quite a full fledged motorcycle. That’s an exciting development because there are a lot of backyard canyons and trails that are off limits to noisy two and four stroke motorcycles. Irritated neighbors and resulting noise pollution regulations have shut down a lot of the local trail riding and canyon carving that was once so popular. 


The new crop of beefy electric trail bikes are more powerful than street-legal electric bikes, but at about 100lbs, much lighter and cheaper than typical full-fledged off-road electric motorcycles. They are quiet enough to allow riding in just about any handy dirt lot, fire road or trail without disturbing the peace or scaring off the wildlife. 


One of the beefy trail bikes that started the movement and best characterize the genre is the Stealth Bomber, developed in Australia. This brute has a top power output of 5,200 watts, enough to propel it to a top speed of 50 mph. It heavy for a bike at 125 lbs, 28 lbs of which is the Crystalite direct drive hub motor. An enormous 72 volt, 1.5 kilowatt- hour Lithium Iron Phosphate pack gives the bike up to 50 miles of range. Long travel full suspension allows riding on rugged terrain.


There is a nine-speed internal gear box for pedaling, although this is not a bike you want to pedal very far without electric assist. Because the bike can be pedaled, it may qualify to be ridden in parks and hiking trails depend on the jurisdiction and local regulations.


Stealth makes a similar cycle called the Hurricane, which has a seat and styling even more similar to a small off-road motorcycle and which has pegs instead of pedals. It is available in two configurations, 84 lbs at 3.7kW output and 105 lbs with 4.5kW motor. Because the frame is slightly smaller and lighter than the Bomber, the Hurricane gets up to about 60 miles in range. Beefy off-road bikes are also available from Bultaco, Elmoto, EMX, Trefecta and M55, with prices ranging from about $5,000 to stratospheric respectively. For comparison, the FX electric off-road motorcycle from Zero, weighs 250 lbs, retails for between $8,500-$10,000 and gets between 35-70 miles of range.


In most places in the US, a street legal electric bike must have fully operational pedals, produce 750 watts maximum power and have a max speed 20 mph on motor only, on level ground, with a 170-pound rider. So in high power configuration these vehicles are classified as mopeds or motorcycles and are banned from some trails or paths. They also require that the rider carry a motorcycle endorsement, registration and motor vehicle insurance when used on public roads. Most of the beefy bikes have a 750W mode so they can legally be ridden as electric bicycles on public roads. But a simple flip of the switch and a healthy twist of the throttle easily propels you past street-legal speeds. Whether called beefy bikes or light motorcycles, these two-wheeled EVs are designed to be fast and fun adrenaline-pumping machines.

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