What is a Vélo à Assistance Électrique (VAE)?
A Vélo à Assistance Électrique (VAE) is a bicycle equipped with a motor powered by a rechargeable battery. Assistance is triggered only when the cyclist pedals, and is limited by regulation to 25 km/h: beyond that, the motor stops working.
There is a wide variety of VAEs adapted to different uses: urban, utility, trekking, travel, electric mountain bike (VTTAE), electric Gravel... To better orient oneself in this wide offer, there are practical online tools, such as this VAE advisor, which lets you define your needs, or this model database listing various electric-assist bikes available on the market.
Two main types of motorization
- Hub motors (housed in the wheel), often equipped with pedaling sensors. They deliver assistance as soon as the pedals turn, without modulating the cyclist's effort. Less efficient in the mountains, they are now rarely used for touring.
- Central motors (integrated into the crankset), which operate with a pressure (or torque) sensor. The motor located at the bottom bracket ensures good weight distribution, as well as finesse in the assistance provided to the cyclist. Assistance adapts precisely to the cyclist's effort, offering a more natural feel and better management of energy consumption. It's the preferred choice for cycle touring and mountain roaming.
Modern VAEs offer several levels of assistance, adjustable according to the desired effort and energy consumption. Some systems also allow these settings to be customized via a dedicated app, as is the case with the eBike Flow app.
Some models incorporate intelligent automatic modes that adjust assistance according to the terrain and the power exerted on the pedals.
The battery: a key element for autonomy
The battery is a decisive element in the autonomy of a VAE. Its capacity generally ranges from 250 to 1100 Wh, with models going up to 1600 Wh in double-battery configuration (2 x 800). For particularly demanding itineraries such as Route des Grandes Alpes ®, it is advisable to opt for a battery of at least 500 Wh, or even 600 or 800 Wh for greater peace of mind.
What autonomy?
The autonomy of a VAE depends on many factors:
- The type of motorization (hub or central motor).
- The battery capacity (expressed in Wh);
- The level of assistance used. Bosch, for example, offers assistance modes adapted to a wide range of riding profiles, from an economical mode to maximize autonomy to more dynamic modes for climbs or relaunches. These modes (Eco, Tour+, Sport, Turbo, eMTB or Sprint depending on the system) modulate effort and adjust power delivery according to terrain, load or riding style.
- The total weight (rider + bike + luggage).
- The profile of the route (flat, hilly, mountain passes).
- The quality of the surface (rolling asphalt or rough roads).
- Bicycle maintenance (tire pressure, chain condition, battery storage).
- Weather conditions (wind, temperature, humidity).
On average:
- A hub-motor and pedal sensor VAE has a range of 30 to 60 km.
- A mid-motor and pressure sensor VAE can go well beyond that with a high-capacity battery and good assistance management.
Beware, however: in the mountains, range can be reduced by 30-50% compared to lowland use, due to the long climbs putting more strain on the motor.
To get a more precise idea based on your profile, route or bike, a tool like autonomy assistant can be used to estimate autonomy, taking all parameters into account.
The VAE is an excellent tool for making bicycle touring more accessible, particularly in the mountains. Thanks to technological advances in motorization and batteries, today they make it possible to envisage long, demanding routes, while controlling effort and autonomy. A good choice of battery and appropriate assistance management are essential to optimize the experience and take full advantage of major itineraries such as Route des Grandes Alpes ® or P'tites Routes du Soleil ®. In addition, certain connected VAE systems can also provide invaluable assistance for navigation, securing the bike or tracking activity, as illustrated on this page dedicated to the connected bike.