Named after Justus B Entz, inventor of the electromagnetic transmission and pioneer in the early automobile industry, the Entz from A2B bikes is their new flagship model. It comes in two builds, and this is the Deluxe model which features Nuvinci’s Harmony gear system.
In a landscape dominated by Bosch and Shimano, A2B have opted for neither of those mid motor systems but instead gone for a new power unit from German giants Continental, best known for their tyres. We saw the Conti eBike System (CeBS) unit in its final development stage at Eurobike last year but now it’s in production, and the Entz is the first bike we’ve tried with the new system. It uses a 250W motor with a high maximum torque of 90Nm, which measures a rider’s input over 400 times a second. The CeBS display is an LCD unit and there’s a remote rocker switch by the grip for changing modes.
The CeBS motor is mated to a Nuvinci Harmony hub which offers full automatic, stepless gear shifting across its range. Unlike hub gears, which use different gears to achieve a number of predefined ratios, the Nuvinci hub uses an arrangement of ball bearings and discs that move relative to one another to make any ratio within the range of the hub a possibility. In manual mode, twisting the shifter changes the ratio from harder ratios to easier ones.
Tap the button on the shifter and the display on the shifter goes blue, and you’re in auto. This sets the hub to a predefined pedal cadence (from around 30 to 90 pedal revolutions per minute) and the hub automatically shifts up or down its range to keep the pedals turning at the same speed. So you just pick a cadence you’re comfortable with, and the hub does the rest. Clever, eh?
Two pretty new technologies, then, and brought together in a very striking frame. The Entz is a low step-through design with a single main alloy beam that extends right from the head tube to the 522Wh-battery-supporting rack at the back. It looks very individual, somewhere in between bike and motorbike territory with its bold lines and 24-inch wheels with big-chamber Kenda tyres. The bike uses an oil-free Continental belt drive and you get a Suntour suspension fork up front and Tektro disc brakes for stopping. The battery can be fitted with a RackTime standard top rack for adding panniers or other luggage. A2B claim a range of up to 100km.
Dave says: It’s a through-and-through interesting bike, the Entz. From the frame design to the component choices, there’s a lot going on. And it all comes together, too. It’s not just some radical experiment, it’s a genuinely likeable and easy-to-ride bike.
The Nuvinci Harmony system will be, I think, a revelation for many. It really works, and it’s so simple in operation, hiding all the necessary and complicated technological stuff behind a simple and easy-to-use interface. Just set it to match your preferred leg speed – you’ll nail it within a couple of minutes – and really you hardly need to touch it again. If you’re heading up steep stuff you’ll benefit from switching to a higher cadence, as the power curve of the Continental motor seems to work better that way. But most of the time, just sit and pedal.
It takes a bit of getting used to from a standstill. When you’re sitting at the lights the Nuvinci hub quietly twists itself back down to a low ratio for an easy start, and when you pull away on green you get a couple of seconds of slightly frantic pedalling before the hub adjusts to your cadence again. It isn’t unpleasant, just different, and it means that you’re slightly slower starting than you would be on a manually-geared bike. For most people that won’t be an issue.
It’s the best auto-shifting system I’ve tried, and that’s down to the fact that it’s stepless, and well implemented. Shimano’s STePS motor can now auto-shift with an electronically-controlled Di2 rear hub gear but switching between the predefined ratios of a hub gear is never going to feel as seamless as riding the Nuvinci in auto does.
The Continental CeBS motor is excellent. It’s near-silent in operation, and the four assistance modes have you covered for everything, with consistent-feeling gaps between them. The Continental belt is quiet too, and should be maintenance-free: there’s no need to lubricate it and it won’t rust.
The 24-inch wheels give the bike quite a low-slung feel and the big-chamber tyres offer masses of grip, even when you lean the bike right over. They’re also very comfortable and you can run them at a fairly low pressure to take the sting out of poor surfaces. They make the distinctly average front suspension fork more or less redundant, and I’d much prefer to see this bike with a rigid or a headshock fork, for the cleaner lines that would give the front of the bike. I’ve no other real gripes though. This is an expensive machine but it’s a really high quality package and the Continental motor and Nuvinci hub offer great performance.