Fat bikes are the go-to machine in the world of mountain biking. It adds spice to the fat biking experience if it’s an e-fat bike. The Cyrusher XF800 is an impressive e-fat bike that is equipped with top-notch features. With a bombproof build and discreetly housed battery, the XF800 provides all-day action. It can take absolute beatings uphill or down with the beefed-up components.

E-bikes mostly use motors and battery options from a few major suppliers: Bosch, Yamaha, Shimano, and Brose. A few other brands exist, but are less reliable or powerful. Some, like the Yamaha system, have more torque, and others, like Bosch’s Active Line, are nearly silent. But, generally, all four make good options. Look for motor output (in torque), which will give you an idea of total power. Just like car engines, more torque equals more power off the line and more boost to your pedaling. But watt hours (Wh) is perhaps a more important figure to use—it takes into account battery output and life to give a more accurate reflection of power (higher Wh equals bigger range).
The unit system is likely to have several options to choose various levels of pedal assistance, which is between 25% and 100% of the pedaling input of the rider. The drive system is most likely to have a smartphone app with features to control various settings including setting up the engine’s support settings, modifying the controls according to the rider’s preference, monitoring the health and charge status of the battery, and more functions.
With most ebikes the choice of motor defines aspects of the frame geometry and to a lesser degree the suspension characteristics of the bike. Not with new Rock Mountain Altitude Powerplay. With its bespoke motor Rocky has been able to design an ebike that reflects the ride quality of a highly evolved 150mm trail bike. With instant power pickup, extended battery life and streamline proportions it’s not just the handling of the Rocky that will get you charged up for riding. It’s the best bike in this test by some margin, but we had an issue with the motor momentarily cutting and raising questions over it’s reliability.

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