A 250W MPF mid-drive motor exudes 500W of peak power and 80Nm of torque.
A torque sensor intuitively moderates pedal-assist to ensure smooth acceleration.
The Gates CDX belt drive is greaseless, quiet and low-maintenance.
An Enviolo TR internal planetary hub offers 380% of stepless gear range.
The Sirius is shod with mighty hydraulic disc brakes, front and back.
With an internally-housed battery, the Sirius sports a neat and clean aesthetic.
The Sirius’s flowing framework is a callback to classic cruisers and klunkers.
Vvolt backs the Sirius with a 3-year warranty against manufacturers' defects.
The Sirius’s battery is lockable and removable for security or off-bike charging.
With a 100mm suspension fork and room for knobby tires, the Sirius is versatile.
27.5” wheels work well in urban and off-road environments.
Moderately upright geometry works well for city and gravel riding.
Acer’s Explova display and control unit is simple, clear and easy to read.
USB lights come included. The headlight connects to the Sirius’s display unit.
Kenda Kwick Seven.5 tires feature a mixed-tread that suits pavement and dirt.
With an internal stepless hub and belt drive, the Sirius operates quietly.
‘Walk Mode’ helps you to walk the Sirius up steep ramps and driveways.
The Enviolo TR hub allows riders to change gears when stopped, without pedaling.
An optional upgrade unit boosts riders’ maximum assist speed to 28mph.

2 reasons not to buy

Due to its quality parts selection, the Sirius is not cheap.
This e-bike’s 375Wh battery capacity is on the lower end of the range.

Bottom line

Vvolt’s Sirius is a Class 1 e-bike that provides riders with pedal-assisted support up to 20mph. An optional ‘Warp Core’ upgrade lifts this to 28mph. The Sirius runs a 250W mid-drive motor that outputs 500W of peak power and 80Nm of torque. A Gates CDX belt-drive and internal, stepless, planetary Enviolo hub combine to produce a quiet, low-maintenance and durable drivetrain. High-quality components are specced throughout. This is not a gnarly trail-riding mountain bike but it is well-suited to gravel riding, dirt roads and crunchy trails. At 375Wh, the battery is on the lower end of capacity but still offers up to 40 miles of range. A stylish and well thought-out e-bike that’s priced accordingly.

By Owen Jesse

Expert Reviews

92/100 based on 1 rated expert review

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Man Makes Fire

Level 1 expert

Vvolt Sirius Electric Bike Review

Level 1 expert

All-in-all, the Vvolt Sirius is a high-quality pedal-assist Class 1 e-bike that can be upgraded to a Class 3 e-bike if you need extra speed… Very highly recommended.

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The Frickin' Shredder

Level 1 expert

Cool New Mid Drive, Belt Drive E-bike

Level 1 expert

Despite the battery, I’m a big fan. I really like the look. I love that it has a mid-drive. I love that it has a belt drive. I love that it has hydraulic disc brakes.

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Ebike Escape

Level 2 expert

Vvolt Sirius E-bike Full Review: Mid-Drive, Belt Drive With Internal Geared Hub!

Level 2 expert

An electric bike like this is much more conducive to pedaling a little bit more… I’m a huge fan of belt drive e-bikes paired with an Enviolo internally geared hub… the biggest selling point is the low maintenance… The Vvolt Sirius is very close to my dream e-bike.

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The Next Web

Level 1 expert

Vvolt Sirius Review: This Low-Maintenance E-bike Is Like Riding on a Cloud

Level 1 expert

There’s a whole lot to like here. While [this price] is no small change, the Sirius feels like it justifies its price. It’s a polished, no-nonsense e-bike with some of the smoothest pedal-assist I’ve tested in a remarkably comfortable design.

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