E-bike conversion kits were all the rage not that long ago, but then it seemed like they went out of favor for awhile, perhaps because the market got flooded with a wide variety of e-bikes, especially those with low price points, and perhaps also because e-bikes were starting to be marketed really hard to those who weren’t already cyclists. And that makes sense, because if you’re looking to get in the saddle of an e-bike as a new-ish rider who wants to be more active, then buying a ready-made electric bike is the way to go. Why dink around with an e-bike conversion kit or a DIY conversion of a traditional bike when you can buy one that’s designed and built from the get-go as an electric bike?
However, there are still plenty of e-bike conversion kits on the market, although some of them that initially got a lot of press back in the day, like the Superpedestrian Copenhagen Wheel (which I got to use and review for another publication back in 2017), have now been discontinued. The Copenhagen Wheel was a great attempt at a “drop-in” e-bike conversion option, but in retrospect, it was way too heavy at 17 pounds and way too complicated and pricey for what it could accomplish (30 miles of range for $1500). It literally replaced your rear wheel, so it completely changed the feel of the bike, and because the battery was located inside the unit and was not removable or replaceable, it probably wasn’t the best design choice.
That being said, with the advent of cheaper and higher capacity batteries and the mass production of electric hub motors by companies like Bafang, e-bike conversion kits with frame- or rear rack-mounted batteries and motors that can be built into standard bike wheels are now widely available. But that hasn’t stopped anyone from creating new types of e-bike conversion kits, and the latest to come across our radar is Skarper.
The Skarper system is a unique take on the drop-in conversion kit, as the unit clips on and off of the chain stay (on the opposite side from the chain and drivetrain), so riders can choose when they want to add electric power to their favorite bike and when they want to ride it without that e-boost. Here’s a brief look at the Skarper:
It’s definitely an interesting way to approach the conversion game, as it uses a “DiskDrive” system that uses a proprietary disc brake rotor (which replaces the existing rotor) with an integrated gearbox that supplies the driving force to the rear wheel. On the one hand, it does require that the bike has disc brakes to begin with (though with disc brakes becoming more of a standard feature these days, especially on higher end bikes, it’s not that far out of a requirement), and on the other hand, being able to quickly install and remove the unit is a big plus. And because the whole system weighs in at about 7 pounds (3 kg for the drive unit and 300g for the rotor), it’s not going to massively change the balance or handling of the bike when installed (obviously your mileage may vary, especially if this is mounted on a very light road bike).
As far as how the Skarper system knows when to kick in, and how much power to provide, it’s described as using an algorithm and wireless sensors:
“To provide all the power you need whilst remaining energy efficient we developed DynamicClimb™ — a bespoke algorithm using a suite of wireless sensors, that measures the rider’s output, road incline and monitors drive unit parameters thousands of times a second. DynamicClimb™ delivers a smooth and powerful ride. Whether it’s accelerating ahead of traffic at a red light, or climbing that steep hill on the way home – DynamicClimb™ will provide the power you need.”
According to the Skarper website, the drive motor is a 250W unit supplying 50Nm of torque, and its 202 Wh lithium battery is said to be capable of up to 60 km per full charge (2.5 hours from empty to full), with a 30-minute charge getting you up to 20 km in range, and the top speed is 32 km/h (~20 mph).
And now for the fly in the ointment: the Skarper is priced at £1,295 (~$1,650), and the initial Launch Edition is already sold out. However, if this strikes your fancy, you can sign up to be notified of the next pre-order deal at the company website.