Compact e-bikes: Small but mighty! – 6 compact 20-inch bikes for city riding and touring put to the test
Georg Bleicher
· 10.03.2024
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These are the six compact e-bikes from the test
“It looks snazzy, but don’t you have to pedal a lot harder on it than on a full-size bike?” a touring cyclist asks us during the test ride. It’s one of the classic preconceptions about bikes with small tyres that just won’t go away. We’ve therefore compiled the five most common misconceptions and set out below to clarify exactly what each one is all about. One thing is certain: e-compact bikes have carved out their own niche because they excel at a number of things. First and foremost: being a family bike. Most compact bikes can be adjusted very easily to suit a wide range of heights – literally in the blink of an eye. In most cases, the range covers riders from around 1.60 to just under 1.90 metres in height. Whether it’s with the ‘Speedlifter’ super-tool, which, on models such as the Kalkhoff Image Advance+ and the I:sy Century, makes adjusting the handlebar height just as easy as adjusting the saddle. Or with a special handlebar stem, as on the Riese & Müller Tinker.
Thanks to their small wheels, compact e-bikes handle more nimbly than other bikes, which is both practical and fun in the hustle and bustle of the city and when manoeuvring at bike racks. Nevertheless, bikes such as the Bergamont or the Riese & Müller provide a sense of security similar to that of a good 28er, thanks to their very stable straight-line ride. As well as the balanced steering geometry, this is of course also down to the excellent adjustability. Another advantage is the low step-through. It’s easier for shorter or older people in particular to step through rather than over the frame. If a child’s seat is mounted on the rear rack, this becomes a struggle on a bike with a top tube of normal height. Even though not all models offer the same ease of mounting (see below), the ease of mounting is vastly superior to that of 28er Diamant frames.
Misconception 1: Tyres and rims that small aren’t sturdy enough.
Actually, small wheels are even more stable than large ones. The smaller a wheel is, the more stable it is, given the same construction. It’s almost a challenge to get a figure of eight into a wheel like that. It makes sense: the longer something is, the easier it is to bend – and that applies to rims as well.
What can a compact e-bike do? Why the name?
Here’s an example: the I:sy is just under 1.60 metres long – a standard bike measures a good 1.90 metres. The same applies to the width required for parking: the I:sy takes up around 29 centimetres (with folding pedals), whereas with a standard bike you need to allow for 55–70 centimetres – in other words, the width of the handlebars – if you don’t want to have to use tools. This space-saving design is useful not only on a car roof rack, but also in a city flat or a small basement storage room. So it’s no wonder that folding and compact bikes are a big hit, particularly in large cities with many very small flats.
Compact e-bikes: Sturdy frames
Compact bikes are usually built around sturdy, cross-frame-style frames. With the exception of the frame on the lifestyle-oriented Cooper UTY, these are very robust aluminium frames with large tube cross-sections, all of which are neatly finished and feature a well-designed mounting for the mid-drive motor, which all the test models are fitted with. Some bikes feature a split rear stay, which allows a drive belt to be threaded through. The Tinker achieves this even more elegantly thanks to a special rear triangle. Here, the chainstay runs not inside but above the belt. This is important because, for an everyday city bike, a belt drive combined with a gear hub is the perfect drivetrain option.
We were particularly impressed by the beautifully crafted frames from Tinker, Kalkhoff and Winora, though in fact all the frames appear to be very well made. ‘Compact’ also means robust and strong: short, thick tubes can withstand more weight than long ones – which is another reason why these bikes are often better at carrying loads than standard models. The bikes’ total weights range from 130 to a hefty 170 kilograms (Kalkhoff) – easily enough for the weekly shop, but not quite a bricklayer’s load.
One exception when it comes to frames: the Cooper UTY’s beautiful steel cross-frame. But that isn’t the only feature that makes this bike the odd one out among the contenders: The bike is less of a family or utility bike – even if the name might suggest otherwise – and more clearly a fun lifestyle machine in the guise of a compact bike, which means it has carved out its own niche. Its light weight, smooth ride and compact dimensions are perfect for a lifestyle bike.
Are compact e-bikes comfortable?
It’s all down to the right combination. If you want more comfort than the wide tyres can offer – which is already quite a lot – you should opt for a suspension seat post like the one on the Kalkhoff. It responds well and can be lowered using a handlebar lever. Stop at the traffic lights, put both feet firmly on the ground, press the lever, and you’re done. When setting off, briefly take the weight off the saddle again, and the post locks into place at the correct height. Want even more suspension? The test Tinker, with its finely tuned suspension fork and equally responsive parallelogram seat post, almost offers a full-suspension feel.
One thing is also clear: high-quality suspension components, such as the Spinner suspension fork, make bikes more expensive. But if that’s important to you, you get a lot in return. Where the small, fat tyres generally perform better than most others is on cobblestones. Even high-quality suspension forks struggle here. Wide tyres inflated to the correct (low) pressure virtually absorb the jarring impact of those annoying cobbles. Important: if the tyre pressure is too low (below 2 bar, depending on the load), the risk of punctures increases. In addition, cornering becomes less precise.
Misconception 2: You have to pedal so much.
That was indeed a common argument against the folding bikes of the 1970s. And: it was true back then. The small wheels meant you could get off to a flying start, but when it came to speed, these bikes were a disaster. To go faster than 20 kilometres per hour, you had to be a master of high cadence. But even back then, there was another way: with gear changes like those on our test bikes. And as a result, regardless of the motor assistance, our compact e-bikes consistently have a gear ratio that allows for a cadence similar to that of large-wheeled bikes. Added to this is the power of the motors, which also make lower cadences possible with minimal pedalling effort.
Misconception 3: E-bikes with such small wheels are uncomfortable.
Firstly, it is true that tyres with a smaller diameter find it harder to ‘swallow’ small obstacles such as a kerb. It’s a bit like how a 30-centimetre step poses a greater challenge for a small child than for an adult, simply because of their shorter legs. However, our 20-inch bikes generally have thick tyres at least 50 millimetres wide. These roll very smoothly even at low pressure. A side effect of this is that they absorb bumps from the road surface much better than narrow tyres, which can only be ridden at higher pressures. So if you inflate the tyres on your compact bike not to four bar, but only to a good 2 to 2.5 bar, you can still ride relatively comfortably. Make sure you follow the pressure specified on the tyre sidewall! Incidentally, the city cyclist’s natural nemesis – the tram track – is no longer such a nightmare with these wide tyres.
Compact e-bikes with plenty of oomph – and weight
Most of the bikes we’ve tested are fitted with variants of the Bosch Performance Line motor, delivering up to a whopping 85 Newton metres. As these bikes are often ridden with a bit of luggage, this can sometimes be useful, though it isn’t strictly necessary. What’s nice, though, is that a powerful motor also turns these compact bikes into fun bikes. The ‘Auto’ mode on the new Smart System version of the motor is both economical and powerful, and it works well on the compact bike too. Particularly in stop-and-go city traffic, a powerful motor can make cycling through town a more relaxed experience. Those who use their bike purely for everyday commuting will be well served by a minimalist handlebar display, such as on the Cooper, which is the only model to feature a very smooth but slightly less powerful Shimano motor.
If you want to find out a bit more or even integrate a sat-nav, you’ll be better off with displays such as the Kiox 500 on the I:sy. All the displays are easy to read, even in poor lighting conditions. Small tyres don’t necessarily mean they’re featherweights – these e-bikes weigh between 24.4 and a hefty 27.7 kilograms. Nevertheless, they’re generally a bit easier to carry than traditional e-bikes, partly due to the frames often being ergonomically designed for a good grip – as with the Kalkhoff’s ‘Griff’ – but also because they’re all fitted with relatively small batteries offering up to 545 watt-hours.This means that, on medium assistance modes, with a rider weighing 75 kilos and on flat terrain, you can achieve an average range of around 55 to 65 kilometres.
Compact, but reliable!
When it comes to safety, too, compact e-bikes are treated on a par with their larger counterparts. For instance, some models feature large 180mm brake discs on the front wheels, which provide consistently crisp and well-modulated braking, though even with 160mm discs, as found on the Tinker and Cooper, the braking performance is adequate. The frame lock, as seen on the I:sy or Cooper, is a boon for city riding. Quickly parking outside the bakery, securing it and – whilst keeping it in sight – popping in to do your shopping makes everyday life easier. For long-term parking, of course, you need a strong lock and a way to secure the bike to a cycle rack or a road sign. A tracking chip integrated into the bike, as on the Tinker, is ideal. This is now available from many e-bike manufacturers and often leads to the bike being recovered in the event of theft.
Misconception 4: One size fits all – it just doesn’t work!
Can compact bikes really suit riders between 1.60 and 1.90 metres tall? And why doesn’t this work with other bikes? The first question is easy to answer. If the saddle height, handlebar height and, where applicable, handlebar angle can be adjusted over a sufficiently wide range, people within this height range will indeed feel ergonomically comfortable. The answer to the second question is more complex. Put simply: it’s down to the small wheels.
The standard wheel size for city and touring bikes is 28 inches. However, there are also other important frame dimensions, including the wheelbase – the distance between the axles. On ‘large bikes’, this increases simply as the rider’s height increases, because otherwise the tips of their feet would come into contact with the front wheel when cornering. If I use a 20-inch front wheel, this doesn’t happen. But if the wheelbase on a 28-inch bike is chosen so that there is no such conflict even for tall people, the bike simply becomes too long for shorter people, and the steering geometry would also be difficult for them.
Panniers on compact bikes?
With a bit of care, it works well. Compact e-bikes are almost always fitted with rear racks suitable for panniers. Because of the small wheels – and particularly with racks featuring a second rail – the panniers hang very low, which benefits the centre of gravity and thus safe handling. You still need to be careful, though – take Kalkhoff as an example: here, the left pannier can rub against the brake disc if it hangs too far back. As a general rule, you should adjust the pannier hooks and the securing bracket precisely and check that the panniers then allow sufficient heel clearance.
On the other hand, it’s very easy to attach panniers to the Bergamont’s cage-like rack without them catching on anything. Incidentally, when riding with 20 kilos of luggage, our compact bikes performed consistently well to very well – better than some low-step models! The lists of useful accessories for the little ones are often long. For example, the I:sy not only offers the classic basket – including one for four-legged friends – and a wide variety of bags, but also special (modular) luggage racks for the front and rear. Adapters are also available, enabling the quick and secure attachment of specialised accessories.
So what do you get for 3,000 to 5,000 euros with these smaller models? Bikes that are ideally suited to city life and the many commutes within it, such as the Radius; bikes that can be extremely comfortable, as demonstrated by the Tinker; or, with the exception of the lifestyle charmer Cooper, are very family-friendly, and – last but not least – offer plenty of riding enjoyment even when carrying luggage, as with the I:sy. In terms of riding position, they’re sometimes more akin to a Dutch bike like the Bergamont, sometimes more like a tourer such as the Kalkhoff, and they handle everything much more smoothly than a sceptic used to a classic 28er would expect. And some of them are already style icons, albeit ones for everyday life...
A comparison of all 6 compact e-bikes
* The range figure refers to the medium assistance mode or ‘Auto’ mode, assuming an active riding style and terrain with very gentle gradients. These are approximate figures for all bikes, which may vary depending on the rider and conditions.
Low-step vs. low-entry
A low step-through is a must for compact e-bikes. However, we’re not talking about 30 centimetres here, as is the case with some city bikes. But whilst a 28-inch bike with a top tube and a medium frame height typically has a top tube height of a good 80 centimetres, the I:sy starts at around 47 centimetres. The Kalkhoff requires 52, the Bergamont 55, the Winora 57, the Riese & Müller around 64 and the Cooper 67. The latter two are certainly not particularly suited to stop-and-go cycling, but even here, getting on the bike is still far more comfortable than swinging your leg over the saddle, and is easily manageable even for shorter riders.
Payload capacity of compact e-bikes: this is how much they can carry
Shopping, DIY, running the kids to activities: our compact bikes are also mini cargo bikes. Here you can see at a glance how much extra weight a 75-kilogramme rider can carry on each bike. Please note: However, this figure does not indicate the load-bearing capacity of the racks. You’ll find this information in the relevant test report.
- Bergamont: 27.3 kilos
- Cooper: 30.6 kilos (carrier: 10 kilos)
- Riese und Müller: 34.5 kilos
- I:sy: 48.9 kilos
- Winora: 50 kilos
- Kalkhoff: 67.5 kilos
Misconception 5: It doesn’t really save any space.
Yes, it is – both in length and width. A size 28 bike has a total length of around 195 centimetres. With our folding bikes, the average is around 165 centimetres. But length isn’t the only factor: on bikes like the Tinker or the Winora, the handlebars can be folded across in a matter of seconds. This means that, instead of the handlebar width (around 50–70 centimetres), the space required at the top is roughly half that. If the bike then has folding pedals, like our Bergamont, the whole bike can be packed away within a maximum width of 29 centimetres.
