The world's lightest e-bike? HPS claims its new Domestique 1-21 is just 8.5kg

HPS has launched its new electronic Watt Assist System on its top-of-the-range road racing bike, that promises to behave like an unassisted road bike and weigh about the same too, at just 8.5kg including all the electronics. 

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The new Domestique 1-21 from the Monaco-based bike brand has a handmade carbon fibre frame and is kitted out with HPS’s new lightweight and well-integrated Watt Assist System, coming in at a total claimed weight of only 8.5kg.  

The Watt Assist System, which includes an 85 Wh (watt-hour) battery, itself weighs in at just 1.5kg, claims HPS. This system is said to be fine-turned with one of Formula 1’s leading engineers to design and build an ultra-light system that delivers on precision.

“Motor, battery and electronics are compact, lightweight and perfectly integrated into the frame: you don’t see these parts and most of all you don’t feel them when riding,” says HPS.

The battery is said to mimic the look and weight of a standard water bottle, and is installed in place of the second bottle in the specially designed Domestique bottle cage, which has been developed in collaboration with Elite.

Two batteries are available to use with the system. Providing up to three hours of pedal-assistance, the standard 193 Wh weighs 1.2kg, while the 85 Wh battery weighs 720g but comes in with just one and a half hours of support. The lighter option does have the benefit of being “flight safe” and can be taken on commercial aircraft, according to HPS.

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The electronics managing the motor and battery are hidden in the down tube. “This is to maintain the design integrity of the bike, positioned low, near the bottom bracket to lower the centre of gravity and not affect the riding dynamics,” HPS says.

A patented freewheel system, which frees the bottom bracket from the transmission mechanism of the motor, is said to ensure pedalling is natural when the system is deactivated.

Maximum motor power stands at 200 watts and the maximum torque is 20Nm.

Who are HPS targeting with this lightweight racing style e-bike?

“There is no typical cyclist, the HPS Domestique 1-21 is perfect for those who want to ride in groups with their fitter friends, for those who want to try extreme riding routes, and also for the rider who wants to keep a specific level of training in a recovery period and thus the bike becomes part of their training program,” says HPS.

Former Team Sky pro Phil Deignan has been the lead development test rider in this project and is available by email and phone to discuss deeper details of the bike in HPS’s “Talk to the expert” service. He is also able to assist in advising how best to use the performance of the bike’s Watt Assist system and how to train with it.

All selected components are Italian: the EKAR groupset is from Campagnolo, the handlebars, stem, seat post and handlebar tape are from Deda Elementi, the 28mm P Zero tyres are by Pirelli, and the Scicon saddle comes from ASG Bike Science.

So, is the Domestique 1-21 the world's lightest e-bike? Our colleagues at eBikeTips have never seen or tested anything lighter, and it weighs a fair bit less than anything on our latest e-road bike buyer's guide. The German innovators Freicycle can build you a modified Merida Scultura with a specially developed friction drive motor concept that weighs in at an astonishing 6.872kg; but the Domestique 1-21 might just be the lightest e-bike built from the ground up to date. 

Want one? The RRP is a whopping €12,000, and delivery is expected within three months of ordering.

hps-bike.com