An e-bike conversion broadened my horizons

This article was published in 2019, in Magazine 142.

Ken Warner (Camcycle Member)

Image as described adjacent

About ten years ago I was able to start cycling again, after a long enforced break. Out went the inherited ancient BSA with sub-optimal 3-speed gears and rim brakes that didn’t work in the rain, in came a city bike with 7-speed hub gears and roller brakes. It’s a good bike and is still the default choice for a quick trip to the shops, but it is quite heavy and wasn’t ideal when I started to explore off-road routes. In due course it was joined by a lighter cyclocross bike, but it was a ride on that (much longer and hillier and very much hotter than expected) that left me struggling to complete the last few miles and was one of the triggers for the next in-depth investigation.

The target was an e-bike – but which one? I was convinced that I wanted a bike that would be comfortable for long rides and pleasant to ride unassisted, so not too heavy. I’d decided that a long distance was easier to cover on-road than off, so it needed to be a ‘road bike’. I tried quite a few, but as recently as 2016 there wasn’t the choice there is now. A Raleigh Captus and a Gazelle Cityzen (in each case with Bosch crank drive) were good but didn’t tick enough of the boxes on my wish list. Another, whose make I am happy to have forgotten, was unacceptable: it was then still possible to find bikes with twist-grip throttles that worked without pedalling. That meant the throttle was still working when I needed to wheel the bike – still, logically, holding the handlebars – and the bike promptly did a dramatic wheely and tried to escape my clutches. It wasn’t just me being silly: I watched exactly the same thing happen to another prospective customer. If there is one hard-and-fast e-bike rule I’ve learned, it is that a well-designed pedal sensor is the right approach, a throttle (now legal only if type-approved) is the wrong approach. Every bike that I’ve liked has had a torque sensor and it makes sense to me that the assistance is related to the pedalling effort. The first turn of the pedals might feel odd, but then there’s nothing that needs thought or an altered riding style – it just feels as if the headwind isn’t so strong, the hill isn’t so steep, or I’m not so tired.

Failing to find ‘just what I wanted’ ready-made, I opted for a conversion. I was lucky to find a new-old-stock audax bike onto which to have fitted a Sunstar crank drive. Sunstar have since withdrawn from the add-on market in response to the increased choice of ready-made e-bikes, so I won’t describe it in detail. Its choice of assistance levels (75/100/150% of rider effort) is narrower than some: a Bosch built-in system available at the time claimed 0/50/120/190/275%. The 75% is fine for me, 100% feels like a lot. The one I miss is 0%: I can switch off while riding, but if I do then I have to stop in order to switch back on. Frankly, that means one item on my wish list was misguided: mine is a pleasant and efficient bike to ride unassisted, but I admit that it doesn’t often happen. Fitting the battery adds about 2.5kg, leaving it off leaves the electrical contacts unprotected from the weather and looks a bit odd, so I routinely set off at 75%. Used like that, only rides of 30 miles or more have used more than half of the battery capacity. Other than initial testing, I’ve hardly ever used the 150% setting.

I opted for a controller which shows speed and distance as well as battery level. Speed is interesting but not something I want to focus on while riding. It is natural (given a good road surface) to get quickly to the 15mph limit of the assistance and settle there: if I drop to around 12mph then perhaps I’m getting tired, or the tyre pressure is low.

Some of the 950 miles I’ve travelled would have been covered more slowly on other bikes, but most were instead of using the car or leisure rides that wouldn’t have happened because they were too far, hilly, hot or windy.

Distance was useful until it was clear that my typical rides were not going to exhaust the battery, although I see now that in about 28 months it has accumulated a total of 950 miles. Some of those miles would otherwise have been covered more slowly on the other bikes, but most of them were either instead of using the car, or leisure rides that might not have happened at all because they were too far, too hilly, too hot, or too windy. It doesn’t sound a lot, but the other bikes are still used when appropriate, and the car doesn’t cover much more than one thousand miles a year.

What would I change? The battery is a smooth cylindrical shape, not the easiest to carry back indoors at the same time as panniers full of shopping, and I was probably wrong to worry so much about overall weight: good balance for good handling is more important.

I also wonder what I’d pick if starting again now. The choice of conversion kits is much smaller and the choice of ready-mades is far greater, so it would be ready-made, with the distinct advantage of allowing proper try-before-buy assessment. There are now e-bikes that are usefully lighter than my conversion, some of them eye-wateringly expensive, others tending to have a smaller motor built into the wheel, and a smaller or built-in battery. A few even allow the motor and battery to be removed for unassisted riding. The built-in battery wouldn’t work for me because I don’t have anywhere under cover to park a whole bike for charging, and a short-range e-bike doesn’t seem to make much sense while I can still use my unassisted bikes for those shorter trips. There are heavy ones too, of course, with more range and even with features such as automatic transmission, but they are expensive. I would make sure that all the electrical components were locked or fixed to the bike: I wouldn’t want to have to carry bits while the bike was parked temporarily. If the handlebars allowed, I’d prefer the controller to be close to the grip, not in the middle. I wouldn’t want one that placed the controls out of reach down by my feet, or one that expected me to use my phone as the display and controller. To make this piece more informative, I should try some of those now available, but I have an uncomfortable feeling I’d buy one that was just ‘convenient’ in all respects and there’s a limit to the number of different bikes I can use. Perhaps it would be one for returning to those off-road routes…