Hidden electric motor for bicycles

A tiny motor and battery designed to be hidden within the frame of high-end road bikes promises to give riders the competitive edge by delivering a secret electric boost.

Hidden electric motor

The Vivax motor slides into the seat tube and connects with the crankshaft via a bevel gear.

The 200 watt motor can be powered by a choice of batteries that run for either 60 or 90 minutes and are housed in a saddle bag or disguised as a water bottle. The control switch can be hidden beneath the seat. The entire package weighs about 2 kg and costs the equivalent of £2,200.

The kit requires Shimano Hollowtech II cranks and a straight seat tube capable of accommodating the 31.6 mm diameter tubular motor.

As it the question of whether a professional rider might try to use the hidden electric motor to cheat in a race, the battery would need to be hidden inside the frame. But as far as detection is concerned, they already make bikes so light that team mechanics have to add weights to the frames for them to be within the legal 6.8 kg so it is feasible that an electric race bike could tip the scales at 7 kg.

Weighing up the advantage

To get the competitive edge, racing cyclists will take a gamble. It might be a new piece of kit, an alternative approach to nutrition or a radical training regime but calculated risks can secure the advantage.

When we looked at how much cyclists are prepared to pay to save weight we found it was as much as £2,000 to save a kilogram of weight. We looked at online prices for new mountain bike prices a couple of years ago and found that a 10kg mountain bike cost £2,483 more than one weighing 11kg on average. The cost per kilogram saved equated to £2.48 per gram; over five times more expensive than the price of scrap silver.

With bike manufacturers charging hundreds of pounds for each pound in weight saved, there’s a financial incentive for you to go on a diet if you are concerned about such things.

It can be hard to find published weights for bikes. Some companies were weighing their small or extra small frames and rounding down, which discouraged others from making the weight of their bikes public.

The ethical choice

The ETA was established in 1990 as an ethical provider of green, reliable travel services. Over 30 years on, we continue to offer cycle insurance , breakdown cover and mobility scooter insurance while putting concern for the environment at the heart of all we do.

The Good Shopping Guide judges us to be the UK’s most ethical provider.