The way the Vivax Assist works differs fundamentally from the classic mid-motor drives of the competition. While Bosch, Yamaha or Brose briefly deliver maximum power of over 500 watts to the chain, the small auxiliary drive from Vivax Assist delivers a maximum of 110 watts to the rear wheel. It is purely a climbing aid. The advantage: the e-bike remains light and easy to handle, rides like a non-motorised mountain bike and the drive is hardly noticeable visually. When the motor is switched off, there is no internal pedalling resistance to slow down the forward momentum.
Depending on requirements, the motor is activated by pressing the thumb on the handlebar switch and the drive starts whirring. It delivers its maximum torque at 75 crank revolutions per minute. This takes some getting used to, as the rider is forced to adjust their cadence as closely as possible to this value. The additional boost makes climbing steep ramps much more relaxed. The battery runs for 1.5 hours with the 9 ampere-hour battery, a 6 Ah version is also available. As soon as the rider stops pedalling, the assistance stops and the power pack has to be reactivated with a click of the thumb. This makes the system particularly suitable for riders who only require a small amount of additional assistance and who do the majority of their tour without a drive. The battery is stowed in the saddlebag and can be removed in a few simple steps.
Until now, the Vivax Assist motor was only available on the market as a retrofit system. It can be retrofitted to bikes with a seat tube that runs straight towards the bottom bracket. From 2016, complete bikes will be rolling off the production line at Vivax. The product range includes three bikes, a hardtail, a fully and a road bike. We took a closer look at the Libero man all-mountain fully.
How the Libero rides with Vivax Assist drive
The classic bike look is noticeable even before you get on the bike. No bulky box on the bottom bracket betrays the e-drive and the small battery hangs inconspicuously in a bag under the saddle. It could be a little more sturdy, the zip opens as soon as you get going off-road. When starting off on the flat, the support remains switched off and the bike feels manageable, the 12.9 kilos (manufacturer's specification) are easy to move. When climbing, the system is activated by pressing the thumb switch. Accompanied by a high-frequency but not annoyingly loud whirring noise, the assistance helps you climb the incline. A maximum of 15 Newton metres is available at 75 revolutions. For comparison: a Bosch CX drive delivers up to 75 Nm. The assistance is slightly more powerful than a Bosch drive in Eco mode. The support is now adjusted via the gear engaged. The lower the gear, the more assistance the drive provides, but the slower the progress. To stop the drive, simply hold the pedals briefly or press the thumb switch again.
The Vivax Libero All-Mountain-Fully has a classic frame geometry with 150 millimetres of suspension travel at the rear and also on the Rock Shox Pike suspension fork. The voluminous 27.5-inch Continental Trail King tyres offer plenty of traction. One drawback: because the electronics are located in the seatpost, telescopic seatposts cannot be fitted. However, there should be a solution for this soon. But the frame offers space for a water bottle.
Test summary of the Vivax Libero
The concept is in stark contrast to the market-dominating mid-motors. The Vivax Assist is not built to surf uphill trails, but to take the fear out of tough climbs. The customers of this system are likely to be primarily interested in making mountain biking a little easier in the classic sense. You won't find any uphill flow here. But if you are looking for an e-MTB that rides like a classic mountain bike and looks like one too, then this is the bike for you.
