Diamant Zouma Supreme+ S in test – How does the 45 km/h S-Pedelec ride?

Bosch Performance Line Speed motor, carbon frame and high-quality components from the mountain bike sector – Diamant want to make the Zouma Supreme+ S a superbike for the city. Does the 45 km/h S-pedelec live up to Diamant’s promises? We put it to the test and here you’ll find all the results and info.

With its carbon frame, the Zouma Supreme+ is the top model in the Diamant portfolio. For € 5,999 you can get the 25 km/h version with Bosch Performance Line CX motor, and for € 6,599 you can get the 45 km/h Zouma Supreme+ S – a so-called S-pedelec. The bikes are identical in construction to the Allant+ 9.9 and Allant+ 9.9 S models from Trek, Diamant’s U.S. parent, except for the paint, saddle and handlebar grips, but each costs € 400 less. We have tested the 45 km/h fast Zouma Supreme+ S for you. It comes with coherent proportions and a sporty look. Despite the wide tires and the voluminous frame, the top tube slopes down towards the rear for a compact appearance, and for an S-pedelec, the Zouma Supreme+ S looks almost delicate.

The individual components such as fork, handlebar, stem and mudguards fit seamlessly into the lines of the main frame, so that there are no hard edges anywhere. Although a total of eight cables originate on the handlebars, they are neatly routed into the stem and are completely routed inside from there on: very well solved. Despite the large lettering, Diamant keep a low profile when it comes to branding, while the carbon black paint finish adds to the bike’s stylish appearance. The workmanship of the Zouma Supreme+ S leaves nothing to be desired and the quality impression is also at a high level for the components. Diamant Zouma Supreme+ S: A coherently styled bike from the handlebars to the tires that cannot hide the Trek genes in its design language.

S-pedelecs are not legally classified as bicycles and are subject to different regulations or registration requirements depending on the country. So before buying, you should check the legal framework for your country.

The engin: Bosch Performance Line Speed

The Diamant Zouma Supreme+ S is powered by the Bosch Performance Line Speed motor, which is fed by an internal 625 Wh battery. The motor brings a maximum torque of 85 Nm and a maximum pedaling assistance of 340% in TURBO mode. Want an example? You bring 100 W, the motor adds 340 W on top. This makes it possible to reach 40 km/h on the flat without much effort. With a little more effort, 45 km/h can be reached over a longer period of time. So this S-pedelec really does run at 45!

The motor also has enough reserves uphill in TURBO mode, but without pedaling at full power, it reaches speeds of 30 or 20 instead of 40, depending on the incline. The acceleration is sufficient to easily swim with the cars in city traffic. This is especially true in cities where the speed limit is now 40. We admit it: We had the most fun in TURBO mode, which is what we drove most of the time. The Bosch PowerTube battery of the Zouma Supreme+ S is located in the down tube and is charged via the well-integrated charging port on the left side of the bottom bracket area. Alternatively, the battery can also be conveniently removed in two easy steps and taken indoors for charging with an integrated handle. You can get to the battery so quickly, comfortably and easily on almost no other bike. Under real test conditions, it is possible to ride a commute of 20 km on hilly terrain there and back completely in TURBO mode. At home, you then have to recharge for the next day. So if you also want to drive exclusively TURBO, your commute shouldn’t be much longer than 20 km. If it is, you either have to recharge at work or get a 500 Wh additional battery for €999 (RRP – online from €900), which is screwed to the down tube. However, the look of the bike suffers and the center of gravity is slightly higher with the additional battery.

At 15% remaining battery capacity, the power is throttled back to ECO level in the TURBO and SPORT modes to conserve the battery and increase the range. The advantages of the powerful engine are then gone and the ride becomes much more strenuous. The throttle cannot be overridden, which is especially annoying when there is only a short hill left on the way to the destination. With the SPORT, TOUR and ECO modes, you can increase the range significantly in some cases – in ECO mode, however, it almost feels like normal cycling. If the battery is completely empty, at a pinch, the bike can also be moved without assistance on flat terrain.

Tech-Talk – Equipment and technical data of the Diamant Zouma Supreme+ S

The Diamant is available in three sizes and was ridden by us in size L. With this, our test riders between 1.80 and 1.90 m tall managed equally well. You can find Diamant’s size recommendations in the table.

Frame size	M	L	XL
recommended for hight	164–177 cm	174–187 cm	185–197 cm
recommended for inseam lenght	78–82 cm	81–86 cm	86–90 cm

The frame and fork of the Diamant are made of carbon, which contributes to the low weight of 23.4 kg and is a real statement in this price range. With the Zouma Supreme+ S, Diamant take full advantage of its affiliation with the Trek group. The frame comes from Trek itself, the stem with integrated cable routing, which makes for a tidy front end, and the Pro Carbon LowRiser handlebar from Bontrager, which also belongs to Trek. The handlebar looks good and plays a big part in the front’s very good vibration damping. For contact points, Diamant rely on a Brooks Cambium All Weather saddle and Brooks Cambium Comfort grips. Both fit the bike’s design very well, but the grips are uncomfortable despite their name and become quite slippery with sweat or rain.

For the gears and brakes, Diamant rely on robust components from the mountain bike sector and so the MTB world meets that of S-pedelecs here – which works very well and absolutely convinces us from a performance point of view. The drivetrain is a Shimano DEORE XT which shifts through the gears quickly and precisely even under full load of the engine. The highlight: It can also shift several gears simultaneously when upshifting – ideal when accelerating from the traffic lights. The gear ratio fits very well with the bike’s speed range of up to 45 km/h.

Braking is well modulated with the MAGURA MT5e, which combines a four-piston caliper from the MTB range with the ebike specific brake lever. The M99 PURE+ headlight comes from Supernova, is equipped with a daytime running light and an automatic low beam. It provides first-class illumination at all times, but no high beam, as the headlights of the latest Supernova generation have. As for the tires, very voluminous semi-slicks are used, which look good and offer decent grip. From splashing water and dirt protect the chic aluminum mudguards, which have an integrated cable routing, whereby the cable of the brake light remains completely invisible. A conventional luggage rack is not to be found on the Zouma Supreme+ S. Instead, it relies on a lowrider aluminum rack to which panniers can be attached on the side – this contributes to the clean look and fits the concept of the bike. Only the included pedals and stand fall visually and functionally in comparison with the otherwise very good equipment. Neither seems appropriate for the bike’s quality standard.

How the Zouma Supreme+ S rides

Let’s come straight to the point: The handling of the Diamant Zouma Supreme+ S is unparalleled in the S-pedelec segment! It is smooth and agile at the same time, never seems nervous, is always predictable and intuitive and thus creates confidence. It has a stoic straight-running ability, which gives security, but can still be nimbly thrown around obstacles.

The bike doesn’t have dampers, but the carbon frame, along with the wide tires, carbon handlebars and seatpost, provide enough compliance at the front and rear to filter out vibrations and minor impacts well. Larger impacts from potholes or curbs, on the other hand, come through strongly. The comfort is completely sufficient for the bike’s range of use in daily commuting, but it is too low for long rides over broken asphalt and gravel. Especially on loose ground, even the wide semi-slick tires, which offer good grip on asphalt, then reach their limits. All controls are arranged so that you never have to take your hands off the handlebars. This makes the controls very easy to use and also improves safety.

Who is the Diamant Zouma Supreme+ S for?

First, let’s answer who the Zouma Supreme+ S is not for: The range is too low, especially in TURBO mode, to ride long tours on the weekend and due to the non-existent suspension, it is not made for bumpy (gravel) roads. The Diamant Zouma Supreme+ S is not allowed to be moved on bike paths in some countries. Thus, at least in these countries, it is not the last mile or city bike to meander through narrow alleys and pedestrian zones. That’s why we don’t see it as the optimal bike to do your daily shopping.

But if you’re looking for a bike that gets you to work and back home quickly and safely every day, underlines your style between smart casual and business casual and is a lot of fun, then you’ll find it here. The Zouma Supreme+ S does this job with flying colors. And by the way, or completely consciously, you are making a statement with the bike: as bike commuters, you are not green-minded idealists – you are the self-confident masterminds of our society, company executives, doers!

The Diamant Zouma Supreme+ S inspires us with its chic design and superior handling. The S-pedelec impresses with a powerful motor, very balanced handling and good brakes. This makes it a confident daily driver for commuters who don’t just have the road as their goal, but who actually want to make a difference. In short: one of the best 45 km/h bikes we’ve ridden so far.

For more information, visit diamantrad.com

Words & Photos: Aaron Steinke