Spain’s brand Orbea recently launched its Diem as a whole new model series – an urban bike that goes its own way and comes up with exciting innovations. In our review, we take a detailed look at this bike and discover whether Orbea’s bold new ideas pay off.

Design

Even at first glance, you can tell that something is different about the Diem: the new frame design stands out with its seat tube, which does not reach down to the bottom bracket as usual – but ends further up on the seat stay. This extends from the rear wheel to the front of the down tube and is intended to provide improved absorption thanks to its flex. An unusual and yet clever approach to increase the riding comfort even without an active suspension! As this functional principle works best with the shape of the frame, the Diem is only available with this unisex frame. Together with the perfectly smoothed weld seams, the aluminium frame looks almost futuristic, which is perfectly emphasised by the metallic matt paint finish in Spaceship Green.

Other components on the bike are similarly modern: a specially developed position light is integrated at the front, which runs around the stem as a narrow strip of light. Similarly, the rear light is integrated flush into the mudguard like a thin strip. There is also a powerful headlight from Supernova, which is integrated directly into the handlebars. It’s rare that a fully-fledged lighting system is so stylishly integrated!

Cables and lines are neatly integrated and routed directly into the frame at the stem. Equally tidy in appearance is the drive system with Shimano’s Nexus hub gears and the Gates belt drive. The EP6 mid-drive motor is certainly noticeable due to its size, but in combination with the unusual frame design it is not distracting. Remarkable is the rather slim down tube, which accommodates a powerful 630 Wh battery. The absence of a display on the Diem also means that the electric drive is not immediately obvious.

Equipment

Let’s start off with the equipment of the electric drive system: The aforementioned battery is permanently installed in the down tube and therefore cannot simply be removed for charging. The 630 Wh of the internal battery can also be extended if required via an optional range extender – an additional battery with 252 Wh, which is formally similar to a water bottle. The Diem 20 tested here is equipped with Shimano’s EP6 mid-drive motor, which is considered the little brother of the well-known EP8. Although the EP6 is somewhat heavier, with a torque of 85 Nm it is on a par with the top model. And overall, the motor is also in the upper range in terms of performance.

The combination with Shimano’s Nexus 5e gear hub is unusual: although it only offers five gears, it is specially designed for e-bikes with powerful mid-drive motors and can therefore also handle the power of the motor. The basic advantages of a hub gear system are of course also present here: such a gear system is maintenance-free and can also be combined with a belt drive — which Orbea has also consistently implemented on the Diem 20 with the Gates Carbon Drive in its CDX version!

The integrated light system is also worth mentioning again: The position light and rear light are developed by Orbea itself, and the rear light also offers a brake light function. The headlight, on the other hand, comes from Supernova and is called Starstream Pure — with 500 lumens and 100 lux, it offers a really full and very bright light!

A smartphone holder for the SP Connect system is integrated into the stem — which was also specially developed for the bike — and there is also a USB-C port for charging the smartphone. The handlebar itself has a rise of 54 mm and is comfortably curved towards the rear, and is also relatively wide at 70 cm.

The tyres are Vittoria’s e-Randonneur with a width of 50 mm, and the sturdy aluminium mudguards are a perfect match. The same applies to the slim and elegant pannier rack, which is compatible with the Ortlieb QL3.1 system and can carry a load of up to 20 kg. For the hydraulic disc brakes, Orbea relies on proven standard equipment in the form of Shimano’s MT201.

There are also numerous interesting options on the Diem: for an extra charge, the bike can be equipped with the Starstream headlight and integrated high beam function (then with 1,000 lumens and 170 lux). In addition to the slim pannier rack on the test bike, there is also a larger one (compatible with the MIK-HD system) and a front pannier rack (with which the headlight unit is then moved to the front of the pannier rack). If you prefer a sportier look, you can opt for a flat bar model instead of the riser handlebar, which also allows the headlight to be integrated.

Operation

The electric drive system on Orbeas Diem is controlled solely via the thumb switch on the left-hand side of the handlebar. Although its design looks like something from the Eighties, it is still easy to operate: the desired speed level is selected intuitively using two large buttons, and an LED indicates this in different colours. The display of the remaining battery capacity also works in the same way, although more precise information could be provided here. If the LED lights up green, the capacity is somewhere between 21% and 100%, below that it lights up or flashes red.

If you’re going on a long tour, you should use Shimano’s smartphone app to check how full the battery actually is. Incidentally, Orbea does not provide its own app and instead leaves it up to the customer to decide whether and which service they want to use for navigation, for example. However, the Diem doesn’t need an app for its actual function anyway, as everything can be controlled directly on the bike.

Thanks to an integrated brightness sensor, the Starstream headlight in the handlebars turns on automatically when it gets dark, while the rear light has to be activated manually (at least once, after which the system remembers the last setting). The trigger for Shimano’s gear hub is located on the right-hand side of the handlebars. Although this comes from the competitor Microshift, it is the more elegant and sportier alternative to Shimano’s own twist shifter. With its two buttons, it is very easy to operate with little effort, only the gear display is the other way round — first gear is the fastest 😉

Due to the permanently installed battery, you inevitably have to move the bike close to a charger. Once there, however, the charging process is extremely simple: the charging socket is easily accessible and can be opened from the top, and the precise charging flap with a fixed catch is commendable.

Apart from that, two other things stand out when handling the bike in everyday life: the steering angle is limited — this means that the bike is stable even with a loaded (optional) front carrier and does not tip over easily. Less practical, however, is the position of the bike stand, which when folded out can easily collide with the pedals when manoeuvring.

Riding impressions

A particularly interesting question with Orbea’s Diem is how well the frame’s flex actually works. Orbea does not provide any specific data on the possible suspension travel, as too many external factors play a role — the weight of the rider as well as the set height of the saddle. And yet you immediately notice, for example when riding over cobblestones, how comfortable the Diem is to ride for a bike with an aluminium frame. In addition to the frame, other factors also play a role here: the riding position is pleasantly upright, also thanks to the riser handlebars installed here with their height increase of around 5 cm. The wide tyres also absorb a few bumps when the air pressure is adjusted low and the wide handlebars give you the feeling that you always have everything under control. It is the interplay of several components that makes the Diem so comfortable to ride.

However, you should also be aware that such a flexing frame cannot perform miracles: compared to other bikes without suspension, the Diem is quite comfortable — but this maintenance-free system cannot (and will not) replace “proper” suspension.

So is the Diem a cosy city cruiser? Not at all! Thanks to the very short stem in combination with the wide handlebars, the bike is super direct and agile to control, while the mid-motor offers more than enough power to guarantee a lot of riding fun. As is typical for Shimano’s EP series, the support is still moderate and linear in the first of the three riding modes, but progressive in the middle mode: the more you pedal, the more support the motor provides. In the third mode, on the other hand, the motor virtually pushes you uphill and the EP6 shows that its high torque is available even with low pedalling force.

These characteristics also make the motor an ideal partner for the 5-speed hub gear. Although its range of 263% is manageable (for comparison: Enviolo’s city and trekking hubs offer 310 to 380%), even steeper climbs in an urban environment are no problem thanks to the motor’s power. Shifting into the lowest gear is therefore a rare occurrence. Instead, you could almost wish for a slightly longer gear ratio in order to be faster beyond 30 km/h.

The fact that the Nexus 5e can handle the full power of the motor is evident in the direct and smooth gear changes. Conventional hub gears (such as Shimano’s Alfine series) quickly reach their limits, especially on hills with a powerful motor and a lot of pressure on the pedals — but even here the Nexus 5e performs its shifting operations without complaint, albeit sometimes accompanied by a slightly louder shifting noise. On the other hand, when things are less stressful, it shifts almost silently, which is a perfect match for the equally quiet Gates belt drive. The motor itself is not silent, but its sonorous and somewhat grinding sound is not noticeable or even annoying.

At 23.8 kg, the Diem 29 (weighed in size M) is no lightweight, but thanks to the powerful drive and agile handling, this is not noticeable during the ride. On the other hand, the bike and its components are stable enough to cope with rough rides over cobblestones without rattling. Incidentally, the maximum rider weight is 115 kg.

Conclusion

Comfortable, practical, sporty and stylish: the new Diem 20 manages to combine all these characteristics in a convincing overall package. Thanks to the special frame construction for an unsuspended bike, the riding comfort is very pleasant, which is also supported by the comfortable seating position. The powerful mid-drive motor leaves nothing to be desired in urban use and forms a strong and reliable team with the hub gears, complemented by the clean belt drive. The fact that the bike is also so agile to ride makes the Diem just as appealing as the clean design with many integrated solutions — above all the first-class lighting system. Orbea’s courage to innovate has definitely paid off!

The fixed battery, on the other hand, can be seen as a disadvantage of the bike — especially as the Diem is not designed to be particularly light. However, it ultimately depends on your personal use case whether this is relevant for you in everyday life. That leaves the price, which is quite high at 4,599 euros — but the bike does it justice.

The Orbea Diem 20 is available in four sizes and three colors (Ivory White, Glitter Anthracite and the Spaceship Green of the test bike). All configuration options and the other equipment variants of the Diem series can be discovered on Orbea’s website.