219 Design has a special interest in last mile transportation, having worked on both scooter and bike solutions. In this teardown, we explore the possibilities for the Segway Drift W1 e-Skates. These skates are the latest innovation from Segway, the company that brought us self balancing personal transportation. They’re like mini-hoverboards for each foot. Currently selling for $389 on Amazon with a battery life of about 45 minutes, a top speed of 7.5mph, and a weight of 7.7lbs, could these skates be a last mile solution? Let’s find out!
Here are the areas of interest we’re exploring for this teardown:
1. Toy or Transportation – Are the skates durable enough to be a last mile transportation solution?
2. Short Run vs. Mass Market Product – Are these skates designed to be mass produced?
3. Max Payload Justification – What features drive the weight limit of 220lbs?
Toy or Transportation?
- The chassis is die cast in magnesium and post machined, a material and process allowing tight tolerances and light weight. For a lower cost, injection molded nylon with inserts would support the loads and threaded fasteners; however, this would not be as durable, nor would it hold alignment (particularly in drafted areas) as well. Metal also provides a better margin of safety for battery issues; it will dissipate heat and contain expanding cells much more effectively than plastic. The choice of metal for the chassis and foot plate suggests that this product is intended to last a long time.
- An extra 5 pieces (1 cast part, 4 grommets) add suspension. This is a significant expense in tooling and parts to improve the ride, a quality only valuable over longer distances and higher speeds.
- The wheel hub is a single steel tube for extra rigidity, particularly to keep the motor magnets from contacting the motor coils. A plastic hub would be less expensive but would require larger gaps between the motor coils and magnets, reducing the efficiency of the motor. High efficiency would not be a important in a toy, but is crucial for transportation products.
- The heat from the motor driver chips dissipates to the chassis via a piece of thermally conductive tape. Effective heat removal from electronics extends their life. It’s a nice design touch to use the cover as both a heat sink and structural element.
- The designers took care to waterproof their wire passages. Rubber grommets, custom gaskets, and a butyl rubber adhesive seal all allow the skates to survive some water abuse. Indeed, they achieved an IP54 rating.
- Blue (not red) thread lockers on all screws.
- Bearings, while more expensive than simple bushings, provide smoother ride and longer life in high-impact conditions. Bushings would be sufficient for a toy with a shorter expected life, but bearings speak to a longer-lived design intent.
- A white caulking compound hardens the electronics against vibrations. Shock loads are particularly aggressive on electrolytic capacitors and will eventually break their solder joints with the board. Adding the white caulk by hand to select electronic components demonstrates a design effort for longer-term reliability.
Toy or Transportation?
With the exception of the chassis, all the castings use simple molds without side actions, reducing the tooling costs and improving mold cycle times. Once out of the molds, two castings required no post-process machining; the chassis requires only simple tapping to finish the part; and a lathe can finish the motor end caps in one fixturing. A good deal of design effort went into optimizing these parts for manufacture, an effort that pays off only at larger production runs. A shorter production run would have seen some of these components machined from stock to keep tooling and design costs low.
The hall effect sensors are a customized version, with insulation and extra long leads, requiring close coordination with the sensor manufacturer. Also, their distance from the the board likely required hand soldering. Together, these elements require close coordination with the electronics supply chain.
Last mile E-transport is dominated by a small set of off-the-shelf motors. These were custom designed for the Segway e-Skates to achieve a high torque within the limits of the wheel hub, with its unusual smaller diameter and larger length.
Taken together, these parts show a pattern of deeper design for manufacturing and an intention by the manufacturer to produce these skates in larger quantities.
Short Run vs. Mass Market
Segway has tooled their assembly line at a level that is only justified for larger-scale production.
Both motor bearings are pressed into interference fits. The high forces in such a fit require a press and tooling to achieve bearing alignment and smooth rolling.
The threaded end of the motor shaft is hollow to pass through wires, which would interfere with a traditional socket that could tighten the nut. Assembly requires a special wrench to achieve the correct torque.
The main body part has several areas with selective powder coating. This process is generally cost-effective at larger quantities, as it requires at least one, likely a few, masking fixtures, and careful application of the powder coating.
Max Payload Justification
Max payload is probably set by maximum torque: The motor’s not strong enough to get 220lbs + up a slope.
The cast metal chassis, with its ribbing around the axel seat and arched internal structure, steel drive axle, and wheel hub are certainly strong enough to stand up to higher loads.
The top plate transmits loads from the rider’s feet to In our estimate, the structure is not a limiting factor.
A close look at the parts of the Segway Drift W1 e-Skates suggests that they can be a transportation tool, intended to be made on a large scale.
Metal, rather than plastic, forms all load-carrying components, and they added several parts to improve ride quality over long distances. The motor was designed specifically for this application, and some effort was put in o optimizing its efficiency. Many parts were also tooled and designed to minimize machining steps.
Taken together, this leads us to believe that Segway intends for their Drift W1 e-Skates to last a long time as a real transportation option.