No bulky look, and it doesn't blow out your spinal discs when stowed in the car - this alone is why the Vivax drive unit has a fan base. The drive unit, consisting of motor, gearbox and freewheel, is concealed in the seat tube. The power is transmitted from above to the bottom bracket via so-called bevel gears. The electronic control unit is located in the seat post and receives the signals from the control unit on the handlebars via radio. The battery is located in a small saddlebag. The system weighs just under two kilos! So much for the technology of the Vivax drive.
The Optimo bike model, the motor manufacturer's own hardtail, rolled into the editorial office for testing. We didn't like its geometry - that much in advance. The steering angle of 72 degrees is simply far too steep, making the bike feel extremely nervous. However, in view of the fact that the Vivax motor is usually retrofitted anyway, we will concentrate on the drivetrain in the following. The concept is not aimed at continuous use, but the motor only wants to be switched on when required. Three support levels are available, which are switched at the touch of a button on the handlebars. Despite its low weight and "only" 200 watts of power, the Vivax provides decent support at the highest level. The mini battery also appears to be of high quality. It only runs out of breath on the test bench at 1102 metres in altitude.
Speaking of going out, and this brings us to the weak point of the system: When the drive is switched on, the system has no freewheel - we therefore advise against using it on uphill trails. The drive should also be switched off before you stop pedalling. Otherwise there will be a small jolt, which will affect the service life of the gearbox.
Conclusion on the Vivax Optimo
Do you lack the last ounce of energy on long gravel climbs? Then you are a potential candidate for the Vivax drive. Bikers who actively use an e-drive off-road will opt for conventional systems.
PLUS Lightweight, slim look, retrofittable
MINUS Operating logic, no permanent support
Technical data Vivax Optimo 27.5"
Reach height 1102 hm
Time/500 hm4 41:06 min
Price 5198 Euro
Drive
Engine Vivax Assist 4.75
Maximum torque
¹
k. A.
Battery¹ / weight² / price Replacement battery Battery 9.0, 9 Ah, 1278 grams / 699 euros
Circuit Shimano XT (2x11-speed)
Translation (v. /h. ) 36/26; 11-40
Display / Size -
Equipment
Fork Rockshox Reba RL Solo Air
Suspension travel¹ 100 mm
Seat post / Ø Vivax Alloy / 31.6 mm
Brake / Disc Ø (front / rear) Shimano XT / 180 mm / 160 mm
Impellers Shimano XT hubs; Alexrims EN 24 rims
Wheel size 27,5''
Tyres Continental RaceKing, 27.5 x 2.2 inch
Measured values²
Sizes / frame material 42 / 45 / 48 / 51 cm /Aluminium
Weight 14.3 kg
Handlebar width 660 mm
Crank length / Q-factor 175 mm / 178 mm
Reach / Stack 422 mm / 616 mm
Manufacturer information
²Determined on the test benches in the EMTB test laboratory, weight without pedals.
The judgement reflects the subjective impression of the testers and the results of the reach measurement and laboratory tests, and is always to be understood in relation to the respective category (hardtail, tour/trail, enduro). The EMTB judgement is independent of price. EMTB judgements: super (from 320 points), very good (from 285 points), good (from 250 points), satisfactory (from 215 points), with weaknesses (from 180 points), below insufficient.
4Average value from the reach height test over the entire distance.
