Usually an ebike lets you know it's an ebike the instant you see it from afar – components like a large hub motor or swollen bottom bracket give it away immediately. But try identifying the new Domestique from Monaco-based company HPS as an ebike, and you'll have a harder time ... even after you already know it's an ebike. The sleek road/race bike relies on an extra-small, lightweight drive system hidden away in the tubes and bottom bracket. The bike offers pedal assistance up to 15.5 mph (25 km/h) while amazingly weighing in well under 20 lb (9 kg).
HPS' Watt Assist Pro drive system serves as the foundation of the Domestique's light build and low profile. Developed in conjunction with F1 engineer Gary Anderson, the system includes a 200-W motor hidden in the seat tube, control electronics in the down tube and other system components housed neatly in the slim bottom bracket. It's quite a departure from the beefy mid-motor systems we're used to seeing on ebikes but still offers the benefit of low center of gravity.
Instead of going the more trendy route in integrating the battery into the down tube, HPS goes old school with a water bottle-style battery. It spent time sculpting its 193-Wh battery to mimic the look and feel of an actual water-filled bottle so that even the most conspicuous component of the e-drive system doesn't feel heavy or cumbersome. The bottle battery mounts to the frame on a custom holder developed in cooperation with Italian water bottle cage maker Elite.
HPS relies on a hand-built carbon fiber frame to keep total bike weight low, achieving a claimed weight as low as 18.7 lb (8.5 kg), with the battery on board and ready for e-assistance. In a world in which any ebike manufacturer that manages to break 30 lbs starts rolling out the "lightest ebike ever" advertising, that's an incredibly low weight, especially for a bicycle that looks like a bicycle.
HPS claims that the Domestique is the lightest ebike on the market, which gels with the fact that the Guinness World Record-holding 15.2-lb (6.9 kg) Freicycle was built as a one-off prototype, a mashup of a Merida bicycle and external e-drive. The Domestique handily beats other bikes, including the recently introduced 26-lb (11.8 kg) LeMond Prolog, the 26.2-lb (11.9 kg) $16,500 Specialized S-Works ebike, the little 23-lb (10.4 kg) Prodrive Hummingbird folder, and the 21.6-lb (9.8 kg) BestiaNera Sport monocoque track bike. It's also lighter than some road bikes without battery power.
Out on the road, the Domestique motor delivers pedal assistance up to a maximum speed, set at 15.5 mph (25 km/h) in Europe and adjusted for other markets according to local ebike speed limit laws. Riders can control output through two modes, each powering through various levels of progressive assistance. HPS promises a gradual phase out of motor assistance when approaching top speed so power doesn't simply drop off precipitously.
According to HPS, the 193-Wh battery delivers between one and three hours of assistance, depending upon setting and usage. Charging takes about two hours. HPS also offers an optional 85-Wh battery that is legal on commercial airlines and has a 1.5-hour runtime and one-hour charge time.
An advantage of a light, sleek electric bike like the Domestique is that it'll be much easier to ride without pedal assistance, whether riding home with a dead battery or pulling the battery off and going without assistance for the full ride. Without the battery, the bike's weight drops by 1.2 kg (2.6 lb), while the freewheel system decouples the motor transmission from the bottom bracket, allowing the bike to pedal normally.
HPS gets the Domestique to market this month with a limited edition launch model. It will build 21 examples of the fittingly named Domestique 1-21 Launch Edition. As usual, the ultimate in weight-cutting design doesn't come without its price — the Launch Edition starts at €12,000 (approx. US$14,450). It includes a Campagnolo Ekar IX13 group set and Pirelli P Zero tires. Lead time is roughly three months.
Source: HPS
