Gboost: we tried to convert a € 289 Decathlon bike into an electric bike

Gboost makes a promise to its customers: the possibility of transforming a standard bicycle into an electric bicycle. We received a kit to give a boost to an iconic Riverside 500 from Decathlon. Is it worth it? Story.

To make an urban journey, the electric bicycle is showing more and more its superiority compared to other modes of transport. Agile, fast, exhilarating and requiring minimal effort which guarantees not to end up swimming in the office, it is establishing itself as the mobility reference for city dwellers.

In 2021, the offer is bloated. And in the middle of these shiny bikes ready to be assembled, there is an astonishing solution, allowing to motorize any biclou that one carries in his heart. This kit lazy is called Gboost and is marketed from 899 to 1,429 €. We tried it out by riding it on an iconic bike that everyone has seen: the Riverside 500 from Décathlon.

How to mount a Gboost on a bicycle

So we find ourselves in the editorial staff with a bike which, very often, is the ideal choice to start with the French sports giant. Lighter and more manoeuvrable than Decathlon’s urban bikes, the Riverside brings a little legacy gravel to driving in town. Its equipment also allows it to be a good road bike which can be quite suitable for Sunday walks. At € 289, this bike also has an incredible quality / price ratio for a new product.

Engine assembly // Source: Louise Audry for Numerama

On the other side of the workshop, we then unpack the Gboost kit. It consists of a few tools – not all the ones you’ll need, unfortunately – a battery with a holder, a motor, a magnet, an on-board computer and a lever to adjust the position of the motor in relation to the wheel. Lots of cables connect these different components to each other and to the handlebars. We received the entry-level Gboost kit at € 899, with a 250W motor and a 251Wh battery. The whole thing adds 2 kilos to the scale, but the components are small enough that they won’t be felt when you pedal. The more expensive Gboost kits, with larger batteries, are worse off at this level.

The finished Gboost kit // Source: Louise Audry for Numerama

The single sheet received as assembly instruction is the bare minimum. We are assured at Gboost that customers will now receive a new document to accompany them in their adventure. We were able to consult it and it takes the opposite view, with its 40 or so pages of instruction. As if the company does not really know how to simplify the assembly to meet its own promise: the 15 minutes we were told have turned into a big hour.

For those who tinker a little, the assembly is not very difficult. We start with the engine lever that is hooked to the handlebars. It will be used to separate the motor from the wheel to regain mechanical control. Next is the engine, which is the part that takes the longest time. We mounted it in place of the crutch by a system of plates which come to hold it under the crankset. Its position is difficult to adjust, especially as a problem quickly arises: the cable that connects the shifter to the derailleur is in our way. For this, Gboost made a small notch in the rubber of its pad, which you have to adjust literally to the nearest millimeter so that it can surround the cable without touching it – we recommend that there are two people for this part.

Fix the battery // Source: Louise Audry for Numerama

Beside the motor assembly, the rest is a breeze. We fix the magnet on the stem of a pedal, we hook the battery holder in place of the bottle holder, we clamp the on-board computer on the handlebars. After a session of cable management to better manage these cables that dangle everywhere, it’s over: the kit is operational.

In practice

It’s time to roll. The on-board computer turns on and we immediately choose the maximum level of assistance to see what the kit has in its belly. First disappointment: the gearshift cable is completely tight in the sheath provided by Gboost and the handlebar control has difficulty communicating with the derailleur. Considering the time this part of the assembly took us, it’s a shame to end up with a half-functional derailleur – Gboost could have imagined a better thought-out system for such a critical component.

Mourning a serene speed shift, we set off on the Parisian tracks. The first pedal strokes are exhilarating: Gboost keeps its promises. Our Riverside is soaring at full speed, with very satisfying dynamics. The time lag between one pedal turn and engine activation is tiny – so much the better, that’s often what spoils the experience of entry-level rotation sensor motors.

The magnet is really badly attached // Source: Louise Audry for Numerama

But 100 meters further, the engine has already shut down.

No electrical failure on the horizon, just the fulfillment of a prophecy spoken out loud a few minutes earlier: ” the magnet fixed with a single plastic clamp, it will never hold »And in fact: the magnet which gives the information to the motor that a revolution of the crank has been made has not held. It ended up at the very bottom of the rod, at the level of the pedal, and its magnetic field could not reach the sensor. In defense of Gboost, the manufacturer advises to add a point of glue that we did not want to put in order to be able to dismantle the kit more easily after our test. But a single plastic clamp and a point of glue to hold an object that will be in perpetual motion and manhandled by vegetation and obstacles, it is very light. As for the speed cable, we say to ourselves that Gboost did not follow through on its idea and could have thought of a more qualitative attachment system.

The channel of the Gboost kit must be oiled to allow the derailleur cable to pass // Source: Louise Audry for Numerama

After having adjusted the magnet in a less precarious position, we set off again. No more worries until the finish, but it’s clear: the pleasure of riding is there. The bike goes wild and the engine, silent, keeps its promises. He pushes us through the streets of Paris without the slightest effort, holding the gaze of passers-by who wonder what this strange assemblage is that goes much too fast compared to what we imagine of him. Held firmly by nuts, the motor does not move, even at high amps.

The handle that allows it to be detached from the bike will be useful if you want to switch back to mechanical driving without having to get off. It is also recommended by the brand to separate it if you anticipate a peak at more than 50 km / h (which is to say that this does not happen with a Riverside 500): the engine is equipped with a dynamo which recharges the battery in descent and, if it spins too fast, it can damage the kit.

Yes, we mounted the computer on the wrong side of the handlebars… // Source: Louise Audry for Numerama

Once the frustrations have passed, it’s clear: the Gboost kit keeps its promises. And maybe with an extra hour of editing, to adjust all the little flaws, we would have had a perfect system.

Who is Gboost for?

But coming back to writing, we can’t help but ask the angry question: who is a Gboost kit for? An electric Riverside 500, assembled and guaranteed by Decathlon, eligible for financial aid from cities and regions, costs € 1,249. Our total assembly, with the bike, comes to € 1,298. At € 1,429 alone, the most expensive Gboost kit costs the price of an entry-level electric bike – even bikes that we recommend with our eyes closed, around € 2,000, which blithely fall below this psychological bar with public aid.

Fast and furious // Source: Louise Audry for Numerama

Clearly, what is the point of buying a Gboost kit? We see three use cases. The first is for lovers of the hack, who want to understand how an electric bicycle works, in a rudimentary way. The pleasure of mounting will amplify the pleasure of pedaling on a boosted bike. The second is for people with a bicycle Teddy, inherited or mottled, impossible to let go out of affection, but which would need a little electric modernity to be used on a daily basis without difficulty. The last concerns those who have already written off the purchase of a bicycle and just wish, on occasion, to take it for a longer ride.

In short, three niches that deserve to know that the solution exists. For others, it is difficult to see the advantage over a real electric bike.

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