Compact e-bikes: Small but mighty - 6 compact 20-inch bikes for city & touring put to the test
Georg Bleicher
· 10.03.2024
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These are the 6 compact e-bikes from the test
"Looks peppy, but don't you have to pedal a lot harder than on the big bike?" a touring cyclist asks us on the test ride. One of the classic prejudices about bikes with small tyres that persist. We have therefore collected the five most important misconceptions and clarify what they are in detail below. In any case, it is true that e-compacts have found their own niche because they can do a number of things very well. First and foremost: being a family bike. Most compact bikes can be adjusted to a wide range of sizes - literally in the blink of an eye. In most cases, the range extends from around 1.60 to just under 1.90 metres tall. Be it with the "Speedlifter" super tool, which makes adjusting the handlebar height on the Kalkhoff Image Advance+ and the I:sy Century as easy as adjusting the saddle. Or with a special handlebar dome like on the Riese und Müller Tinker.
Due to their small wheels, compact e-bikes run more smoothly than other bikes, which is practical and fun in the hustle and bustle of the city and when manoeuvring at the bike stand. Nevertheless, bikes like the Bergamont or the Riese und Müller give a feeling of safety like a good 28er thanks to their very relaxed straight-line stability. In addition to the balanced steering geometry, this is of course also due to the good adjustability. Another advantage: the low step-through. For smaller or older people in particular, it is easier to climb through than over. If a child seat is perched above the rear carrier, this becomes difficult on a bike with a normal top tube height. Even if not all bikes offer the same ease of access (see below), the ease of access compared to 28er diamond frames is enormous.
Misjudgement 1: Tyres and rims this small are not stable enough.
Yes, small wheels are even more stable than large ones. The smaller the wheel, the more stable it is with the same structure. Getting an eight into such a wheel is almost a challenge. Understandably, the longer something is, the easier it is to bend - and this also applies to rims.
What can a compact e-bike do? Why the name?
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 you need to calculate for parking: The I:sy needs about 29 centimetres (with folding pedals), whereas a normal bike needs 55-70 centimetres, i.e. handlebar width, if you don't want to carry tools. This quick streamlining is not only useful on a car rack, but also in a city flat or small cellar. So it's no wonder that folding and compact bikes are all the rage, especially in big cities with lots of very small flats.
Compact pedelecs: Sturdy frames
Cross frame-like, stable frames usually form the basis for compact bikes. With the exception of the frame of the lifestyle Cooper UTY, these are very robust aluminium frames with large tube cross-sections, neatly finished throughout and with successful mounting of the mid-motor, which all test subjects rely on. Some bikes have a separable rear stay that allows the drive belt to be threaded in. The Tinker does this even more elegantly with a special rear triangle. The chainstay does not run inside but above the belt. This is important because the belt drive, combined with a gear hub, is the perfect drive option for an everyday city bike.
We particularly liked the beautifully crafted frames from Tinker, Kalkhoff and Winora, but all the frames actually look very well made. Compact also means robust and strong: short, thick tubes can take more load than long ones - which is another reason why these bikes are often better load carriers than the normal bikes. The system weights of the bikes are between 130 and a whopping 170 kilograms (Kalkhoff) - easily enough for a week's shopping, but not yet a bricklayer's load.
An exception when it comes to the frame: The beautiful steel cross frame of the Cooper UTY. However, this is not the only feature that makes the bike a bird of paradise among the candidates: the bike is not so much a family or utility bike - even if the name suggests this - but clearly a lifestyle fun machine in the guise of a compact bike, which therefore has its own niche. Lightweight, smooth running and small dimensions also suit a lifestyle bike.
Are compact e-bikes comfortable?
It's all about the right combination. If you want more comfort than the wide tyres can offer - which is quite a lot - you should opt for a suspension support like the one on the Kalkhoff. It responds well and can be lowered using the handlebar lever. Stop at the traffic lights and place both legs safely on the ground, press the lever and you're done. When riding off, briefly take the weight off the saddle again and the seat post engages at the correct height. Even more suspension? With its fine suspension fork and parallelogram suspension post, the test Tinker almost feels like a full suspension bike.
It is also clear that high-quality suspension components such as the Spinner suspension fork make bikes more expensive. But those who value them also get a lot out of them. What the small, fat tyres can do better than most others is cobblestones. Even high-quality suspension forks fail here. Wide tyres filled with the correct (low) air pressure almost bounce the annoying stones away. Important: However, if the tyre pressure is too low (less than 2 bar depending on the load), the risk of puncturing increases. In addition, cornering becomes less precise.
Misjudgement 2: You have to pedal so much.
This was already a popular argument against the folding entrance bikes of the 1970s. And it was true there. The small wheels meant you could get off the ground quickly, but in terms of speed, these bikes were a mishap. You had to be a master of high cadence to reach over 20 kilometres per hour. But that would have been possible in a different way even back then: with gears like those on our test bikes. And as a result, regardless of the motor support, our compact e-bikes all have a gear ratio that enables a cadence similar to that of large wheels. Added to this is the power of the motors, which also make lower cadences possible with little pedalling power.
Misjudgement 3: E-bikes with such small wheels are uncomfortable.
First of all, it is true that smaller tyre diameters "swallow" small hurdles such as a kerb less easily. Just as a 30-centimetre step is more of a challenge for a small child than for an adult due to their shorter legs. However, our twenty-inch bikes always have thick tyres that are at least 50 millimetres wide. These tyres roll very smoothly even with little pressure. Side effect: They absorb shocks from the ground much better than narrow tyres, which can only be ridden with higher air pressures. So if you inflate the tyres of your compact bike to a good 2 to 2.5 bar instead of four, you can ride relatively comfortably. Pay attention to the pressure indicated on the tyre sidewall! By the way: The natural enemy of the city biker, the tram track, also loses its terror with wide tyres.
Compact e-bikes with bang - and weight
Most of our test bikes rely on variants of the Bosch Performance Line motor with up to a whopping 85 Newton metres. As these bikes are often ridden with some luggage, this is sometimes useful, but not absolutely necessary. What is nice, however, is that a powerful motor also turns the compact bikes into fun bikes. The Auto mode of the new Smart System version of the motor is economical and yet powerful, which also proves its worth on the compact bike. A powerful motor can make travelling through the city more relaxed, especially in stop-and-go traffic. If you use the bike purely as an everyday bike, you can get by with a minimalist handlebar display, as on the Cooper, which is the only bike that relies on a very harmonious but slightly less powerful Shimano motor.
If you want to find out more or even integrate navigation, displays such as the Kiox 500 on the I:sy are a better option. All displays are easy enough to read even in poor lighting conditions. Some small tyres are not yet flyweights - the e-bikes weigh between 24.4 and a whopping 27.7 kilograms. Nevertheless, they are usually a little easier to carry than classic e-bikes, which is partly due to the often ergonomically easy-to-grip frame, such as the Kalkhoff with "grip", but also to the fact that small batteries with up to 545 watt hours are installed throughout, which means that with medium support modes, a rider weight of 75 kilos and flat terrain, you can achieve an average range of around 55 to 65 kilometres.
Compact, but safe!
The compact e-bikes are also treated like big bikes when it comes to safety. For example, some of the front wheels have large 180 mm brake discs, with which the bikes decelerate in a crisp and well-dosed manner, but the deceleration is also appropriate with 160 mm discs, as on the Tinker and Cooper. The frame lock, as on the I:sy or Cooper, benefits the city affinity. Quickly park in front of the bakery, secure it and - within sight - go shopping, which makes everyday life easier. For long-term parking, of course, you need a strong lock and a connection to a bicycle bracket or a traffic sign. A tracking chip integrated into the bike, as in the Tinker, is perfect. This is now available from many e-bike manufacturers and often leads to the bike being recovered in the event of theft.
Misjudgement 4: One size fits all - it doesn't work!
Can compact bikes really fit people between 1.60 and 1.90 metres tall? And why is this not possible with other bikes? The first question is easy to answer. If the saddle height, handlebar height and possibly also the handlebar angle can be adjusted sufficiently wide, people within this size range will actually feel ergonomically comfortable. The second answer 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 other important frame dimensions, including the wheelbase - the distance between the axles. On "big bikes", this increases with the height of the cyclist alone, because otherwise the tips of the feet would come into conflict with the front wheel when cornering. If I use a 20-inch front wheel, this doesn't happen. However, if the wheelbase of a 28-inch bike is chosen in such a way that there is no such conflict even for tall people, the bike will simply be too long for short people and the steering geometry would also be difficult for them.
Panniers on compact bikes?
With a little care, it works well. Compact e-bikes are almost always equipped with rear carriers suitable for panniers. Due to the small wheels and especially on carriers with a second railing, the bags hang very low, which benefits the centre of gravity and thus safe handling. Nevertheless, you have to be careful - take Kalkhoff as an example: the left bag can drag on the brake disc if it hangs too far back. Basically, you should adjust the bag hooks and the securing angle precisely and test whether the bags then offer sufficient heel clearance.
On the other hand, panniers are very easy to attach to the cage-like carrier of the Bergamont rack without bumping into anything. When riding with 20 kilos of luggage, our compacts performed consistently well to very well - better than some step-through bikes! The lists of useful accessories for the little ones are often long. The I:sy not only offers the classic basket - including one for four-legged friends - and many different bags, but also special (system) luggage racks for the front and rear. Adapters are also available that allow special accessories to be attached quickly and securely.
So what do you get with the little ones for 3000 to 5000 euros? All bikes that are predestined for the city and many commuting routes, like the Radius, that can be extremely comfortable, as you can see on the Tinker, that are very family-friendly, with the exception of the lifestyle charmer Cooper, and last but not least offer a lot of riding fun, even with luggage, like on the I:sy. In terms of position, they are sometimes more like a Dutch bike like the Bergamont, sometimes more like a touring bike like the Kalkhoff and really ride everything in a much more balanced way than the sceptic coming from a classic 28er would expect. And some of them are already style icons, even if they are from everyday life...
All 6 compact e-bikes in comparison
* The range information refers to the medium support mode or "Auto" mode with an active riding style and terrain with very low gradients. These are approximate values for all bikes and may vary for different riders and conditions.
Comfortable beginner vs. deep beginner
A low step-through is a must for compact e-bikes. However, we're not talking about 30 centimetres like some city bikes. But while we have to reckon with a top tube height of 80 centimetres for a 28-inch bike with a medium frame height, the I:sy starts at around 47 centimetres. The Kalkhoff requires 52, Bergamont 55, Winora 57, Riese und Müller around 64 and the Cooper 67. The last two are certainly not particularly stop-and-go-friendly, but even here, climbing is still far more comfortable than swinging your legs over the saddle and is also feasible for smaller people.
Payload of compact e-bikes: this is how much they can carry
Shopping, DIY store, children's taxi: our compact bikes are also transport bikes in miniature. Here you can see at a glance how much a rider weighing 75 kilograms can still carry on the respective bike. Please note: However, this value says nothing about the load capacity of the carrier. You can find the data in the respective test report.
- Bergamont: 27.3 kilos
- Cooper: 30.6 kilos (carrier: 10 kilos)
- Riese and Müller: 34.5 kilos
- I:sy: 48.9 kilos
- Winora: 50 kilos
- Kalkhoff: 67.5 kilos
Misjudgement 5: This doesn't really save space.
Yes, and as long as it is wide. A 28er bike has an overall length of around 195 centimetres. The average length of our folding bikes is around 165 centimetres. But length isn't everything: on bikes like the Tinker or the Winora, the handlebars can be folded in seconds. This means that instead of the handlebar width (about 50-70 centimetres), we need about half the space at the top. If the bike then has folding pedals, like our Bergamont, the whole bike package can be accommodated on a maximum width of 29 centimetres.
