SWYTCH UNIVERSAL E-BIKE RETROFIT: PRO
From £999: from Swytch eBay/Amazon stores, but with up to 50% discount if you wait for a pre-order window on Swytch’s website
Larger battery option (as tested) £1250 full RRP.
Extra weight added - 4.45kg (as tested)
Swytch are a UK-based company run by a young team with an engineering background who successfully launched the Swytch kit via crowdfunding several years ago. They have four retrofit electric kits on offer designed to bring a new lease of electric life to an existing non-powered bike – Eco, Pro (larger battery and inbuilt front light) and a Brompton specific one which also comes in both Eco and Pro. All four aim to make electrifying your bike as quick and easy as it possibly can be.
Do they succeed and how does the kit fare when it gets out into the Pennine hills?
This review comes courtesy of electricbikereport.com contributor Richard Peace.
Electricbikereport.com features hundreds of e-bike reviews, guides and a weekly news post to keep you abreast of all things e-bike.
Why would you want to spend money on an electric retrofit kit when the likes of Halfords and Decathlon offer pretty decent e-bikes for around £1000? (The full RRP of the Swytch kit is £999 to £1250 – but note those who register with Swytch during a pre-order window can get up to 50% discount on full RRP).
Well, it’s a light kit and if you happened to have a light bike you could end up with a light e-bike – there aren’t that many of these about and those that exist are often pretty pricey. In my case I wanted to electrify my touring bike, a much-loved Tout Terrain model. At 15kg+ it was no lightweight to begin with, but I wanted to keep it as light as possible as an e-bike. It was also a ‘custom build’ being the result of whatever rather high end parts London’s Bikefix happened to have lying around and surplus to requirements. This meant I would end up with an e-bike with a very high spec, including Hope hydraulic disk brake, Shimano external bottom bracket bearings and 8 Alfine hub gears – most likely to be found on an e-bike costing several thousand.
Clearly, Swytch’s great success to date has been because they have latched onto the fact there are many thousands of little-used bikes in sheds around the country. A promise of being able to fit the kit to virtually any bike would only need to appeal to a small proportion of those ‘shed bikes’ to equal plenty of sales.
What is the Swytch Kit?
There are three main parts to the kit – front motor wheel, pedal sensor assembly (or throttle for ‘US spec’ versions) and battery plus interface and wiring nexus that mounts on the handlebars.
1. The motor is of the geared type (you may also see gearless motor kits on sale but these tend to be heavier and less efficient than geared ones and I wouldn’t recommend them for most conversions). It comes ready-spoked with rim tape (but no tyre or inner tube) and Swytch has standard wheel sizes of 28", 26" and 16" (Brompton) in stock. Rims come in black or silver and they also offer custom build service for other sizes. The only non-compatible wheels will be those with thru-axles which tend to appear on high end mountain bikes and so are much less likely to have such a kit fitted.
2. The universal pedal sensor has just gone through a redesign and can be easily configured to fit around the pedal crank on the opposite side to the chainwheel. It is essentially a circle of twelve magnets that communicate with a separate sensor fixed to the bike frame via a small sticky pad. Sensor and magnet wheel can be aligned using small Allen-head bolts so that they line up accurately – the idea being to get the magnets to pass as close to the sensor as possible without touching it.
3. Battery options are 180Wh (‘Eco’ kit) and 252Wh (‘Pro’ kit, which is what I fitted). Both are relatively small capacity batteries as e-bikes go so if you think you can manage the extra weight of the larger pack on your handlebars I would recommend the larger option (smaller wheels and thinner tyres are more likely to mean a ‘twitchy’ handling bike and the smaller pack may suit you better – hence the Brompton option is specced with a 180Wh battery).
The battery is housed in a sturdy looking canvas bag along with the control electronics. This removes easily from the mounting block (which is clamped to the handlebars) at the push of a button. To control the power levels or turn the system on and off and use the inbuilt light, you use the buttons found on top of the battery pack.
Straight out of the box it looks a well-made and unique design; whilst the motor is no doubt ‘off-the-shelf’, Swytch have clearly put a good amount of work into the designing very practical looking battery assembly and pedal sensor. This is not a kit that is straight out of a far eastern factory and simply rebranded, as so many are. The emphasis has clearly been on making the Swytch lighter and easier to fit than others.
Fitting – Is it Really That Easy?
It took me around half an hour going quite carefully and steadily – an adjustable spanner and standard range of Allen keys, plus tyres levers and pump will do the job. It should be within the ability of all with modest bike maintenance skills and if you don’t fancy it should be a cinch for a bike shop.
It’s a case of swapping tyre and inner tube and slotting in the new wheel, attaching the pedal sensor components around the pedal crank area, and fixing on the battery mount. Finish off by connecting motor and sensor to the leads on the underneath of the battery mount. All leads are colour coded and the different connection configurations make it impossible to connect the wrong part to the wrong lead.
My Tout Terrain has large rotor hydraulic disc brakes with a centrelock mount. Whilst all Swytch motor wheels come with mounting points for disc brake rotors, these use the more standard Allen bolt mounting system so if your bike has the centre lock mounting system the easiest solution is to buy a new Allen bolt disc rotor of the correct size (that shouldn’t be expensive – around £7.50 in my case).
There is plenty of information on the Swytch website about how to order the correct wheel size and you should also be aware that 9.5mm of space around the handlebar stem is needed to fit the battery mount. You should also check the width of the dropouts on you bike – 10mm is standard and that is what Swytch supplies, but some forks may be 9mm – if so Swytch can supply a motor wheel with a 9mm axle (it’s also possible to file a 10mm axle down to 9mm at the correct point if you are careful - but that is your own responsibility).
The two main safety points in fitting are to make sure that the anti-turn washers fit into the dropout space snugly and to ensure the restraint strap on the battery mount is fitted correctly. The first ensures the axle stays firmly in place despite the twisting forces on it and the second that battery stays horizontal and doesn’t slip down.
So – as with many jobs – the work is as much in the preparation and measuring as in the job itself. The only bikes that the Swytch definitely won’t fit are those with thru-axles and hub brakes which should be a very small minority.
Naturally the Swytch kit doesn’t give the full on power of a top end Bosch-style crank drive or similar, but that option is both heavier and pricier. However, for a light weight hub motor I found it performed excellently. For real heavy duty applications like load hauling and more demanding off-roading you might be better looking elsewhere, otherwise the Swytch will deliver smooth and lively power that will make tackling hills and headwinds easy.
Unlike cheaper power delivery systems, power came in quite quickly once I started pedalling and stopped when my legs stopped turning – not always the case with these pedal assist systems (PAS) – especially the cheaper ones.
Changing between the five power levels was the only aspect of the system I felt need improving as you need to take a hand off the handlebars to change settings, which can be quite tricky if the surface underwheel is uneven. A separate handlebar control mounted next to a grip would be the answer.
My range test in moderately hilly Pennine country: distance came out at 26 miles, which is pretty impressive at nearly 10 watt hours of battery consumed per mile. The eight hub gears on the Tout Terrain no doubt helped efficiency – don’t expect such efficiency if the kit is fitted to a single speed! The battery capacity meter was fairly crude, as most voltage based ones are, but certainly by no means the worst I have tried; and it does give an approximate estimate of how much battery power you have left. As is the case with many smaller batteries, expect power to drop off slightly as the battery approaches the empty level.
When the battery is empty it shouldn’t be too hard to keep pedalling on an efficient bike as the motor freewheel runs nice and easy.
Does the extra 2kg weight of the battery on the handlebars affect handling? Not really – at least not on this particular bike with stable 28” wheels and reasonably wide profile tyres – the effect was felt more when off the bike as it tends to quickly swivel the bars to one side, so some care was needed when leaving it propped on the kickstand.
The inbuilt light that comes with the larger battery bag of the Pro version is a nice touch and acts as a highly visible safety light in built up areas, but for illuminating unlit country roads and tracks you will need something more powerful. Swytch provide handy strap type mounts on the front of the bag if you don’t have space on your bars for more lights.
How does Swytch stack up against other retrofit kits? In terms of quality, ease of use and efficiency Cytronex still has few, if any, rivals – though compared to Swytch there are no deep discounts available and the battery is considerably smaller. Nano which is similar in performance but a bit more basic in quality does offer a throttle (a great option for nipping through commuter traffic) and it also offers the flexibility of using generic Bosch powertool batteries – but it’s limited to Bromptons. ARCC is the best quality of all but much pricier and somewhat heavier than the Swytch and limited to a certain number of bikes. The Vekkit system from Poland looks to share the bar bag system with Swytch and has wireless power control and appears very lightweight, but I have no further info about it, at present.
Though I haven’t tried a wide range of other kits I would wager most are either heavier or more complex to fit than the Swytch – or even both. In terms of universality of fit and value for money (at the discounted price at least) Swytch appears to have few rivals.
Weight: Removable battery / controller pack weight = 2.1kg (252Wh capacity option)
Total kit weight = 4.45kg (this is the effective weight the kit added to the bike calculated by weighing the bike before and after the kit was added, not the actual weight of all kit components – weight may be gained or lost by the difference in weight of the new rim, spokes and, where applicable, disc brake rotor). Before fitting the bike weighed 15.65kg and after fitting 20.1kg giving an overall gain of 4.45kg.
Motor: Geared front hub motor.
Battery: Eco option 180Wh, Pro option 252Wh.
Power Delivery: 12 magnet pedal sensor.
PUBLISHED MARCH 2021