Boost’s take on a lightweight ebike conversion kit is effective, runs smoothly, and is a more straightforward, cost-effective method of powering up your non-assisted bike than front-wheel systems from brands such as Swytch.
It comes in plenty of options to suit your needs, although you'll need some technical knowledge to nail down the best setup for your bike.
The Boost ebike conversion kit can be ordered through a network of bike shops, and fitted by them if you don’t feel confident doing it yourself.
You can also order a do-it-yourself kit for £522 and build your own wheel, or opt for Boost’s full service, which includes building a wheel to match your bike.
The wheel can be supplied in a 120mm singlespeed dropout width, 130/135mm road quick-release format or as a 142mm thru-axle specification. You can also choose disc, hub or rim-brake options.
I opted for Boost to build a wheel for my donor bike, a 2013 Genesis Day One singlespeed cyclocross bike.
Boost built a disc wheel to match the original black Alexrims 24 shallow disc rims, with a black Ryde rim that had a matching 19mm internal width.
The fully built wheel, delivered along with the Boost kit, is priced at £674. Add in the wireless head unit (£59) and a handy cold-weather cover for the battery (£19.99) and the total price comes to £752.99.
Compared to rival ebike conversion kits, the Boost is priced keenly; Skarper’s premium click-on click-off system is more expensive at £1,495. The Cytronex kit comes in at around £1,000, depending on specifications. Swytch’s equivalent-range MAX+ kit is £999.
Boost ebike conversion kit setup
Fitting the Boost kit is relatively simple with minimal tools, although a bit of preparation is required. My kit arrived with simple instructions and plenty of online help options.
The disc-specific bolt-on 135mm rear hub slotted into the frame easily.
My bike was set up for a 140mm rear disc rotor. The hub is designed around 6-bolt rotors, though, and when I fitted the wheel, the bolts fouled the oversized Genesis dropouts.
The sliding singlespeed dropouts are also ready for a hub gear. Switching the rotor for a 160mm one and adding a 160mm brake adaptor sorted these issues (thankfully, I had both in my spares locker, but it’s worth checking with Boost about your requirements when ordering the kit).
The only other niggle was my initial idea of fitting the battery on the seat tube bottle cage bosses didn’t pan out. The bosses on the Day One are much lower than standard because it was never designed to run a front derailleur. This meant the large bottle cage (which houses the controller for the motor and battery) fouled the down tube.
Because of this, the only place the cage and battery could fit was on the down tube bosses.
Boost provides a handy downloadable battery/cage template on its website, which you can print to check your bike – but you’ll need to ensure your printer settings are uncropped.
Even with these unexpected complications, though, I had the Boost kit fitted and ready to run within 35 minutes of unboxing it.
You can add to the setup by pairing it with either the Boost app (available for iOS and Android) or the optional wireless head unit controller. Neither is necessary to use the Boost, although I recommend the added ability to switch modes with the optional head unit.
Before the changes, the bike tipped the scales at 10.3kg, and with the Boost kit fitted, it weighed 14.65kg (including pedals and Garmin mount/light). Boost’s claim of 4kg for the system (depending on wheel choice) rings broadly true.
A £699-when-new, 10-year-old bike might be worth less than £100 second-hand – add the £752.99 of my Boost kit specification, and you could argue this represents an electric bike for less than £1,000.
To boot, it’s a good few kilos lighter than a complete ebike for around that price with a similar specification. Pure Electric's Flux One tipped the scales at 17.3kg.
The 216Wh battery has an on-off switch and a USB output, which means it can double up as a power bank charger. Its 6,000mAh-equivalent capacity is enough to charge an iPhone around four times – handy for weekends away and bikepacking trips. The battery, since this test has been updated to a 252Wh capacity, at no additional cost, which should see a range increase by around 5 miles/8km.
Boost ebike conversion kit performance
Boost’s 250W rear-hub motor delivers a claimed 42Nm of torque at 350W, with a peak power of 500W. This is in line with so-called ‘full’ ebike systems such as Mahle’s X35 and Kynamic’s rear-hub motor.
The power delivery is smooth, and because it’s matched to your speed, it’s very efficient on flat and rolling roads, delivering impressive range from a minimal battery.
However, because it’s not measuring or matching your cadence (and therefore power input), it can feel underpowered when you’re grinding up a steep climb. You can counter that by upping the boost level from ‘Eco’ to the ‘Super-Boost’ mode on the controller.
I found when using the second-highest ‘Boost’ mode to commute over relatively flat terrain, I didn’t need to shift modes.
Super-Boost gives a 20-second max-power hit that’ll get your cadence and speed up quickly. Because I’d used the kit on a bike with a single 40/18t-gearing setup, I needed this mode on steep climbs, where I was lacking the necessary gearing.
It’s worth noting that spinning the 40/18t gear at a reasonable 80-90rpm means riding at around 15mph (25kph), running 40mm-wide gravel tyres.
The relatively modest 216Wh battery capacity doesn’t suggest a big range, but I was pleasantly surprised that on a mixed-surface ride (the majority of which was a flat towpath with a couple of road climbs thrown in) it achieved a maximum of 40.5mi / 65.2km with 1,329ft / 405m of ascent.
Bearing in mind that’s on a bike with a single gear, the Boost is an impressive package for the price.
Boost ebike conversion kit bottom line
I used the Boost kit to revive a bike I hadn’t used for many years – my daily commuter bike when the office was much closer, but since then, it has languished in the dark reaches of my garage.
I now have a bike that’s just as much fun to ride as it always was, but it’s now a practical commuter and run-around again, thanks to the addition of the Boost kit.
The simple-to-remove battery and understated rear-hub motor, with no other sensors, keep the bike looking standard, and therefore less attractive to thieves.
Like Swytch and Cytronex, and myriad cheap online ebike conversion kits, the Boost kit is intended to stay on your bike. Therefore, I’d recommend if you’re considering buying one, thinking of it as a permanent change. For the sort of ebike kit you can take off, your only option is a Skarper system.
However, if, like me, you’re looking to revive an old bike for a new purpose, Boost has a great option for much less money than the competition.
Product
| Price | £522.00 |
Features
| Features | Boost rear motor 250w disc hub, built onto black anodized rim, stainless spokes, high-pressure rim tape, 18-tooth singlespeed sprocket |
