HKM-7715411 Folding Fat Tire E-Bike Carries a 750W Hub and a 48V 13Ah 624Wh Pack on 20 x 4.0 Tires for the Beach

750W · 48V 13Ah 624Wh · 20 x 4.0 · 37 mi · folding frame · 20 mph · rear rack

A Mid Frame Hinge That Turns a Fat Bike Into Airline Carry OnFolds Small and Still Rides Very Far

A 750W rear hub, a 48V 13Ah 624Wh pack in the frame, 20 x 4.0 fat tires, a suspension fork and mechanical disc brakes, on a frame that folds at the middle. It is listed at 37 miles and 20 mph, and the point of it is not the numbers: it is that a fat tire bike you can put in a car boot is a fat tire bike that goes on holiday with you, into a boat locker, or under a desk in a flat with no hallway, which is a narrow brief that this class of bike fills and a full-size fat bike does not.

Most fat bikes live where they are parked, because a 70 lb bicycle on a roof rack is an argument waiting to happen. This one folds at the frame and drops the bars, so it goes in the back of a hatchback, the locker of a boat or the garage of an RV, and that changes what the bike is for: beach weekends, forest campsites, and the kind of trip where a rented bike would cost more than the fuel.

The 20-inch wheels are the compromise that makes the fold work. They accelerate quickly and they keep the folded package small, but they read every crack in a pavement that a 26-inch wheel would swallow, and the fat casing is doing most of the comfort work that a bigger wheel would do on its own. That is the trade, and it is a fair one for the trips this bike is bought for.

At a Glance

• 750W Rear Hub — Brushless hub with throttle and pedal assist
• 624Wh Pack — 48V 13Ah in the frame, key-locked
• 20 x 4.0 Tires — Fat casing for sand, gravel and snow
• Folds at the Frame — Middle hinge and dropping bars
• 37 Miles Listed — Pedal assist, less on the throttle
• 20 mph — As configured, not a speed machine
• Suspension Fork — Coil sprung, with a rigid rear
• Mechanical Discs — Front and rear, cable actuated
• Rear Rack — Frame mounted, for a bag or a crate
• Fenders — Front and rear, fitted
• Car Boot Size — Folds small enough for a hatchback
• LCD Display — Speed, battery, assist and trip

Frame, Fold and Fat Tires

The frame is a single-hinge folder in aluminium, with a second release on the stem so the bars fold alongside the front wheel. The whole sequence takes about thirty seconds and needs no tools, which is the difference between a folder that travels and one that stays folded in a garage.

Up front there is a coil-sprung suspension fork; the rear is rigid. On 20 x 4.0 tires that is enough: the tire is the first half of the suspension, the fork is the second, and a rear shock on a folding frame is a complication most makers sensibly avoid.

The cockpit carries a display in the middle, a throttle on the right and a 7-speed shifter under the left hand. The bars fold down rather than telescoping, so the folded package stays low enough to slide under a shelf or into a car boot.

• Frame: aluminium, single middle hinge
• Stem: folding release, no tools
• Fork: coil-sprung suspension
• Brakes: mechanical disc, front and rear
• Tires: 20 x 4.0 puncture-resistant
• Drivetrain: 7-speed

Fitted as shipped: front and rear fenders, a rear rack, an LED headlight, a kickstand and the battery keys. The tires are 20 x 4.0 with a puncture-resistant casing, which is the right call on a bike that spends its life on gravel and beach paths.

Motor, Battery and Range

The motor is a 750W brushless rear hub. On a 20-inch wheel it feels quicker than the number suggests, because the wheel spins up fast, and it is strong enough to move a loaded rack through soft sand at walking pace without stalling. A geared hub freewheels when you stop pedalling, so the bike coasts like a bicycle on a descent instead of dragging the motor behind you. The controller is sealed and the wiring runs inside the frame, so a wet beach day is not an electrical problem.

The pack is 48V 13Ah, 624Wh, 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 into a tent or a cabin when the bike is parked outside. The charger is a 48V brick that lives in the same bag as the bike when you travel, and the pack comes out with a key if you would rather leave the bike in a car overnight.

Range is listed at 37 miles on pedal assist, less if you ride on the throttle, and less again in cold weather or on sand. For the trips this bike is bought for, that is two days of short rides between charges rather than a week of commuting. On sand the throttle is the difference between a long walk and a short ride.

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 folding stem and long seatpost do most of the adjustment. Short riders get a foot down easily on 20-inch wheels, which is why this platform also sells to riders who find a full-size fat bike intimidating.

On sand and gravel it floats and tracks straight; on pavement it is quick to steer and firm over cracks, and the small wheels make it feel more agile than its weight suggests. It is not a bike for long distances, and it does not pretend to be.

• Beach weekends, campsites and RV trips
• Car boot transport and holiday rentals replaced
• Short errands on gravel and packed sand
• Not for long-distance touring or fast road riding

What's in the Box

Before the first ride: unfold the frame and check both releases are seated, fit the pedals, set the seatpost height, check the brakes and bed the pads in, then charge the pack. Fold and unfold it once at home before you rely on it in a car park in the rain.

Color and Finish

Matte black covers the frame and fork, with black rims, a black cockpit and grey graphics on the main tube. The paint is deliberately plain, because a folding bike gets folded against car bumpers and boat lockers, and a plain finish hides that better than a glossy one.

Touch-up paint is available on request. The wear points are the hinge, the stem release and the chainstay under the chain, and the hinge is the one to keep clean.

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 624Wh pack charges in an evening, and on a trip it is worth charging indoors rather than in a cold car. On a trip, charge it indoors rather than from a car inverter.

Check tire pressure before every ride: 15 to 20 psi on pavement, 8 to 12 psi on sand. Check the folding hinge for play monthly, keep a drop of oil on the pivot, and check the brake pads and the spoke tension on the rear wheel after the first 20 rides. The hinge is the part that decides whether the fold still feels solid after a season, so clean it and check it more often than the rest of the bike.

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-7715411 · 20 in folding fat tire electric bike · 750W brushless rear hub · 48V 13Ah 624Wh pack in the frame, key-locked and removable · 37 miles listed range · 20 mph as configured · 7-speed drivetrain · mechanical disc brakes front and rear · coil-sprung suspension fork with a rigid rear · 20 x 4.0 puncture-resistant tires on black rims · LCD display · throttle and pedal assist · LED headlight · front and rear fenders · rear rack · folding middle hinge and folding stem, no tools · matte black with grey graphics · built for beach weekends, campsites and car boots rather than long-distance touring · geared hub that freewheels on a descent · battery key-locked in the frame · five to six hour charge · ships with charger, keys, tool kit and manual · folds with no tools in about thirty seconds