HKM-3527891 Folding Fat Tire E-Bike Runs a 1500W Peak Hub on 26 x 4.0 ARISUN Tires With a 1200Wh Pack for Off-Road

1500W peak · 1200Wh · 26 x 4.0 · 31 mph · 1000W rated · folds · 80 Nm · 87 mi

A Big Pack a Strong Hub and Tires That Hold Loose GroundBuilt for the Long Way Round Home

A rear hub rated at 1000W with a 1500W peak and 80 Nm, a 48V 25Ah 1200Wh pack inside the down tube, ARISUN 26 x 4.0 off-road tires on cast alloy wheels, and double-piston hydraulic brakes with 180 mm rotors. It folds at a rear hinge, it is listed at 50 miles on throttle and 87 on assist, and it tops out at 31 mph. The 1200Wh pack is one of the largest in this class, the ARISUN casing is a real off-road tire, and the whole thing still folds at a hinge behind the seat tube.

The two things that make this bike unusual are both structural. A 26-inch fat bike that folds is rare, because the hinge has to sit in a frame that is also carrying 1200Wh of battery and a 99 lb bike's worth of load, and cast alloy wheels instead of spoked ones remove the tension checks that a fat bike normally needs every few months. That combination is why it weighs 99 lb, and why the folding is worth reading carefully rather than assuming it turns the bike into something you carry.

Folding it does not turn it into a commuter folder: it is still 26 inches of wheel and four inches of tire, so it goes in the back of a van or a large SUV rather than a hatchback. What folding buys is storage rather than transport, and the hinge is the part to check before every ride because it carries the whole rear triangle.

At a Glance

• 1500W Peak Hub — 1000W rated, 80 Nm, brand figures
• 1200Wh Pack — 48V 25Ah inside the down tube
• 50 to 87 Miles — Throttle and pedal assist, listed
• 31 mph — 50 km/h listed
• 26 x 4.0 ARISUN — Off-road casing on cast alloy wheels
• Double Piston Brakes — Hydraulic, 180 mm rotors
• Folding Frame — Rear hinge, 26-inch wheels
• 6061-T6 Frame — Hydroformed, triple-butted alloy
• 80 mm Fork — Suspension travel up front
• 99 lb Complete — A two-person lift
• 331 lb Rating — 150 kg for rider and cargo
• 7-Speed Shimano — Geared to pedal a flat pack home

Folding Frame and Cast Wheels

The frame is hydroformed, triple-butted 6061-T6 aluminium, with the battery inside the down tube and a hinge at the rear triangle. Triple-butting is why a frame this size can carry 1200Wh and a 331 lb rating: the tube walls are thicker where the loads are and thinner in the middle.

The wheels are cast alloy rather than spoked, which on a fat bike is a maintenance decision. There is no spoke tension to check, nothing to go out of true at low tire pressures, and the bead seat holds better at 8 psi. Bend one and it is a replacement rather than a true.

Up front there is a suspension fork with 80 mm of travel and an inverted double-crown look; the rear is rigid. On four-inch tires that is enough for gravel and fire roads, and the rigid rear is what keeps a loaded rack from bouncing against a pivot.

• Frame: 6061-T6 alloy, hydroformed, triple-butted
• Folding: rear hinge
• Battery: 1200Wh inside the down tube
• Wheels: cast alloy, 26 in
• Brakes: hydraulic, 180 mm rotors
• Tires: ARISUN 26 x 4.0 off-road

Fitted as shipped: front and rear fenders, a rear rack, a front rack hoop with the headlight built into it, a kickstand and the battery keys. The brakes are double-piston hydraulic with 180 mm stainless rotors front and rear.

1500W Peak and 1200Wh

The motor is a rear hub the brand quotes as 1500W peak and 1000W rated, with 80 Nm. That distinction matters: 1000W is what it can hold on a long climb and 1500W is the burst it draws from a standstill. Quoting only the larger number would mislead you about how it behaves on a hill, and quoting only the smaller one would undersell how it leaves a stop. It is a geared hub, so it freewheels when you stop pedalling.

The pack is 48V 25Ah, 1200Wh of 18650 cells, inside the down tube and charged through a port on the frame with a 48V 3A charger. It is one of the larger packs in this class, which is why the range figures are what they are, and it is also a large part of the 99 lb weight. At 3A it is an overnight charge rather than a lunchtime one, so plan the evening before a long day.

Range is listed at 50 miles in Class 2 throttle-only mode and 87 miles on pedal assist. Those are brand figures on level ground with a light rider, so plan a real off-road day around 40 miles with the throttle in use, and treat 87 as the assist-only best case on a hard surface.

Who It Fits and How It Rides

One frame size covers riders from about 5 ft 5 in to 6 ft 5 in, and the 26-inch wheels put the saddle higher than a 20-inch fat bike does. Shorter riders should sit on one before ordering, because the standover on four-inch tires is taller than the number suggests.

On gravel, dirt and packed sand it is stable and the wide casing floats, and the double-piston brakes are the part that matters once the rack is loaded. At 99 lb it is a two-person lift into a truck bed.

• Fire roads, farm tracks and packed dirt
• Camping and hunting trips with a loaded rack
• Storage in a van or garage where a 26-inch bike will not fit upright
• Not for tight singletrack, stairs or a hatchback boot

What's in the Box

Before the first ride: check the hinge is fully seated, fit the front wheel and check the axle, set the fork preload for your weight, bed the hydraulic brakes in with ten firm stops, then charge the pack. Fold and unfold it once at home before you rely on it in a van.

Color and Finish

Space grey covers the frame and the battery cover, with orange stripes on the down tube, black cast wheels, a black fork, black fenders and a black rack. The orange on grey is the whole colour scheme, and it is the part that makes the bike readable from a distance.

Touch-up paint in the matching grey is available on request. The wear points are the hinge, the cast wheel faces and the chainstay under the chain.

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 1200Wh pack on a 3A charger takes most of a night, so start it in the evening rather than an hour before you leave.

Check tire pressure before every ride at 15 to 20 psi on pavement and 8 to 12 psi on dirt, and check both axles and the hinge after the first 50 miles. Check the hydraulic pads monthly, and check the rear spoke tension is irrelevant on cast wheels but the hub bolts are not: check those with the pads.

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-3527891 · 26 in folding fat tire electric bike · rear hub quoted at 1500W peak and 1000W rated, 80 Nm, brand figures · 48V 25Ah 1200Wh pack of 18650 cells inside the down tube, key-locked · 50 miles throttle, 87 miles assist, listed · 31 mph, 50 km/h · Shimano 7-speed drivetrain · double-piston hydraulic brakes with 180 mm stainless rotors · 80 mm suspension fork with a rigid rear triangle · ARISUN 26 x 4.0 off-road tires on cast alloy wheels · rear hinge fold · rear rack and front hoop with the headlight built in · front and rear fenders · hydroformed triple-butted 6061-T6 frame · 331 lb load rating · 99 lb complete · space grey with orange stripes · 48V 3A charger · UL listed · built for fire roads, off-road days and camping rather than tight singletrack, stairs or a hatchback boot