HKM-9432019 Fat Tire E-Bike Runs a 750W Hub on 20 x 4.0 Tires with a 48V 15.6Ah Pack and Twin Rear Shocks for Two

750W · 48V 15.6Ah 749Wh · 20 x 4.0 · 28 mph · twin rear shocks · hydraulic discs · 265 lb

Twin Coil Shocks and Hydraulics for the Road That Just EndsSuspension That Follows the Rough

A 750W rear hub, a 48V 15.6Ah 749Wh pack in the frame, 20 x 4.0 knobby tires, a sprung fork with twin rear coil shocks and hydraulic disc brakes, under a long bench seat. It is listed at 37 miles and 28 mph with a 265 lb rating, and the bench plus the rear shocks are what separate it from the usual 20-inch fat bike: two people can sit on it and neither feels every crack, which is not true of a fat bike with a rack pad bolted over a hardtail.

The frame is a black step-through with a flat bench seat rather than a saddle and post. That changes how the bike is used: you sit on it rather than over it, the bars come back to you, and a passenger behind you is sitting on the same seat instead of on a rack pad. The 265 lb rating covers both of you. A saddle on a post is adjustable; a bench is not, which is the trade you make for the shape.

Twin coil shocks at the back and a sprung fork at the front put this a step above the hardtail fat bikes in the same size class. On 20-inch wheels that matters more than it does on a 26-inch bike, because the small wheel finds every crack in a pavement and the suspension is what keeps the ride from becoming a series of jolts.

At a Glance

• 750W Rear Hub — Brushless hub with throttle and pedal assist
• 749Wh Pack — 48V 15.6Ah in the frame, key-locked
• 37 Miles Listed — Pedal assist, less on the throttle
• 28 mph Listed — Above the Class 3 line in most states
• 20 x 4.0 Knobby — Fat casing for gravel, sand and snow
• Twin Rear Shocks — Coil shocks plus a sprung fork
• Hydraulic Discs — Front and rear, with motor cut-off
• Bench Seat — Long flat seat, two-up length
• 265 lb Load — 120 kg rating for rider and passenger
• Rear Rack — Frame mounted behind the bench
• LCD Display — Speed, battery, assist and trip
• Grille Headlight — Round LED lamp at the front

Frame, Bench and Suspension

The frame is a black step-through with a long flat bench on top, and the battery sits inside the frame rather than on a rack. It is a shape built for sitting upright with your feet forward, closer to a small motorcycle than to a mountain bike, and the bars are pulled back to match.

Suspension is at both ends: a sprung fork up front and a pair of coil shocks under the rear of the bench. That is unusual on a 20-inch fat bike at this price, and it is the part of the bike a passenger notices first, because the rear seat is sitting on the springs rather than on the frame.

The cockpit carries an LCD in the middle, a throttle on the right and the usual brake levers. The round headlight is set in a grille at the front, and the whole front end is deliberately over-built for a bicycle, which suits the style of the thing.

• Frame: black step-through
• Seat: long flat bench, two-up length
• Fork: sprung, with a grille headlight
• Rear: twin coil shocks
• Brakes: hydraulic disc, front and rear
• Tires: 20 x 4.0 knobby

Fitted as shipped: front and rear fenders, a rear rack behind the bench, an LED headlight, a kickstand and the battery keys. The tires are 20 x 4.0 knobby, which is what makes a gravel path and a packed beach usable rather than an adventure.

Motor, Battery and Range

The motor is a 750W brushless rear hub with a throttle and pedal assist. On a 20-inch wheel it spins up quickly, which makes the bike feel livelier than the wattage suggests, and the rear hub keeps the steering light because there is no motor weight between the fork legs. A geared hub, so it also freewheels when you stop pedalling rather than dragging the wheel behind you on a descent.

The pack is 48V 15.6Ah, 749Wh, key-locked in the frame and removable for indoor charging. A full charge takes five to six hours on the supplied charger, and the pack is light enough to carry indoors in one hand when the weather turns cold. The lock sits on the frame rather than the pack, so the cover stays with the bike when the battery comes out, and the charge port is sealed against a wet ride.

Range is listed at 37 miles on assist, and less if you ride on the throttle with a passenger aboard. Cold weather, sand and a second rider all pull that down, so plan a 10-mile round trip on two charges a week rather than one. The low figure is the honest one when there are two of you aboard.

Who It Fits and How It Rides

One frame size covers riders from about 5 ft 2 in to 6 ft 2 in, and the bench means the effective seat height is fixed rather than adjustable. Taller riders will feel their knees come up; shorter riders will find it easier than a saddle-and-post bike of the same wheel size.

On gravel and packed sand it floats and the shocks keep the bench level; on pavement it is stable and the knobby tread hums. With a passenger aboard the bike is calmer at low speed and slower to stop, so leave more room than you think you need.

• Beach towns, campgrounds and gravel paths
• Two-up errands with a passenger on the bench
• Short city hops where style matters as much as speed
• Not for tight singletrack or long-distance touring

What's in the Box

Before the first ride: fit the front wheel and check the axle, set the rear shock preload for the weight you plan to carry, bed the hydraulic brakes in with ten firm stops, then charge the pack fully. Check the bench bolts before you take a passenger.

Color and Finish

Matte black covers the frame, fork, rack and rims, with a black bench and a black cockpit and the model name in white on the battery cover. It is a deliberately monotone scheme, and the only colour on the bike comes from the orange reflectors on the wheels.

Touch-up paint is available on request. The wear points are the chainstay under the chain, the bench edges and the frame where the rack bolts on.

Battery Care and Maintenance

Charge the pack between 20 and 90 percent for daily use and take it to full about once a month so the management system can balance the cells. A 749Wh pack charges in an evening, so there is no reason to leave it at 100 percent in a warm hallway for a week. Charge it indoors at room temperature rather than in a cold garage.

Check tire pressure before every ride: 18 to 20 psi on pavement, 10 to 12 psi on sand. Check the bench bolts and the shock preload whenever you carry a passenger, and check the hydraulic pads monthly, since two riders wear them faster. Check the spoke tension on the rear wheel after the first 20 rides, since a hub motor loads that wheel harder than a bicycle hub does, and check the shock bolts at the same time.

Specifications

Frequently Asked Questions

Service and Policies

Coverage that lasts beyond the box. Orders ship free with a tracking number in 2 to 5 business days. From delivery, the product is protected for 180 days against manufacturing defects and transit damage, returnable within 30 days for a full refund, and covered by a 24-month parts-and-labor warranty on manufacturing defects. Four policies, one idea: ship it free, protect it for 180 days, take it back for 30, and stand behind it for two years.

HKM-9432019 · 20 in fat tire electric bike · 750W brushless rear hub · 48V 15.6Ah 749Wh pack in the frame, key-locked and removable · 37 miles listed range · 28 mph listed · 20 x 4.0 knobby tires on black rims · hydraulic disc brakes front and rear with motor cut-off · sprung fork and twin rear coil shocks · long flat bench seat, two-up length · LCD display · throttle and pedal assist · round grille headlight · front and rear fenders · rear rack behind the bench · 265 lb load rating · matte black · built for beach towns, campgrounds and two-up errands rather than singletrack · geared hub that freewheels when you stop pedalling · key-locked pack with a sealed charge port · five to six hour charge · ships with charger, two battery keys, tool kit and manual · fenders and rear rack fitted at the factory