Tested: Merida eSilex 400

Tested: Merida eSilex 400

08.07.21 04:39 4.908Text: Gabriel Waringer (translated by Carola Felchner)Photos: Erwin HaidenFun, affordable and silent. Merida's gravel bike with hub drive motor inspires our tester to the point of riding with the chemical brothers. A solid proof of versatility, isn't it?08.07.21 04:39 4.909

Tested: Merida eSilex 400

08.07.21 04:39 4.909 Gabriel Waringer (translated by Carola Felchner) Erwin Haiden Dieser Beitrag ist auch in Deutsch verfügbarFun, affordable and silent. Merida's gravel bike with hub drive motor inspires our tester to the point of riding with the chemical brothers. A solid proof of versatility, isn't it?08.07.21 04:39 4.909

Questions that I’d rather answer “yes” to, but actually are a “no” are usually questions of a rather unpleasant kind, e.g., when the dentist asks me if I floss regularly. It becomes even more unpleasant when my girlfriend asks me if I know what special day it is today. Or, worst case scenario, when I am in desperate need of an easier gear on a climb, ask myself whether there might be one, but learn the bitter truth when trying to shift down with shaky fingers.

While the first two situations are relatively easy to defuse (Lie to the dentist, it doesn't matter anyway and always go for the “your birthday” answer with your girlfriend), the third scenario presents us with a problem. What’s left to do when there is no hope of being saved, the end of the climb seems to be in unattainable distance, and you are close to tears?

Push the button!

When it comes to the new Merida eSilex, the answer is quite simple. You press the iWoc button, which is integrated into the top tube, sit back, and relax, because you will immediately feel as invincible as Asterix after a sip of Miraculix's legendary magic potion. Or at least up to 250 watts stronger – which is almost the same in my case.

For the 2021 model year, Merida incorporated a new old e-bike concept into their line-up: hub drive motors. They are made by Mahle, called x35+, and are quite light in contrast to other common e-bike drives. The complete system weighs just under 3.5 kilograms, including battery.
This flyweight has less power than the big players in the mountain bike world (Bosch, Shimano, Brose, Yamaha, etc.), but with up to 40 Nm of torque, there’s no need to hide. Though definitely it is good at hiding. At first glance eSilex and its non-motorised twin almost look identical. Also, the 250 Wh battery is inconspicuously hidden in the slim down tube. Well done, Merida, well done!

Mahle’s x35+ in detail

In spring 2021, the former Ebikemotion hub drive was first written about in this magazine. So, if you are interested in learning more about Mahle’s x35+, please go to NoPain's test report of the Scott Addict eRide.

Do it again!

The concept of hub drive motors might seem antiquated, but it has some advantages: especially on road bikes and gravel bikes the crank’s Q-factor significantly determines the riding experience. As there is no mid-motor, a normal crank can be ridden. You might even mount a power meter crank without any problems.
The hub drive motor also has a positive effect on the overall weight of the bicycle, which in the case of eSilex 400 amounts to 14.1 kilograms. Quite lightweight though there’s still no need to worry about undercutting the UCI’s weight limit of 6.8 kg.

As already mentioned, there is no display on the handlebars or elsewhere to activate the motor. This is done by pressing a single button integrated into the top tube and nestled into an LED ring and that's it.
This kind of motor control takes some getting used to, as different light colours indicate the support level: white means no support, green light support, orange stronger support, red full support – 250 watts, baby! The support level is selected via double click.

What’s great about the Mahle system are the Bluetooth interface and smartphone app – these allow for bike configuration via mobile phone in no time. The Ebikemotion app turns your phone into a cycling computer because basic information such as speed, riding time and altitude metres is clearly and legibly displayed on the screen. In addition to the basic functions of a simple bike computer, battery charge level and current motor support are also displayed. Not bad!

Furthermore, the app may also be used for navigation – no need for a Garmin or similar device as long as your mobile phone’s battery is charged, and you are willing to pay for the respective map (e.g., € 4.49 for Europe in the iPhone App Store).

Tech Specs

Frame eSilex Lite Crankset Shimano GRX600, 10s, 46/30, 175 mm (XS/S: 170, M: 172,5)
Sizes XS, S, M L, XL Bottom bracket Shimano BSA
Engine Mahle x35+ Cassette Shimano CS-HG50, 10s, 11-36 Z.
Battery Mahle B1-C, 250 Wh Stem Merida Expert IR, 31,8 mm, 5°, 80 mm
Display Mahle iWoc Bluetooth + App Handlebar Merida Expert GR, 440 mm (XS/S: 400, M: 420)
Fork Merida Silex CF2, tapered Wheels Merida Comp SL rims, 17 mm/VP CLK170F CL hubs, 100x12 mm
Headset VP-MH-P16 Tires Maxxis Rambler 700Cx40
STIs Shimano GRX400, 10s Saddle Merida Comp CC
Brakes Shimano GRX400, 160/160 mm Seatpost Merida Expert, 30,9 mm, 0 mm SB
Rear derailleur Shimano GRX400 Weight 14.4 kg (w/o pedals)
Front derailleur Shimano GRX400 Price € 2,699 SRP

Get up on it like this!

Apart from the motor, the eSilex is quite like other gravel bikes: the main frame is made of aluminium and accommodates tyres up to a width of 45 mm on 28-inch wheels. With mounted mudguards, there’s still enough room for 42-mm tyres. The bike is, however, also available with 650b wheels and matching 50-mm tyres.
The robust Shimano GRX400 groupset ensures reliable shifting. The option of a double chainring crank on an e-bike is also interesting – the GRX600 with 46/30 combo puts you at ease no matter what climb lies ahead. Only the fork is a bit out of line, as the frame was given a massive 1.5" head tube to steer the maximum permissible total weight of 120 kg safely and precisely around every corner.
I also liked the numerous mounting points in the main frame and on both sides of the fork. A lowrider for panniers can effortlessly be mounted, as well as an additional rear rack, both options that turn eSilex into a genuine touring bike.

The eSilex thus combines the sporty appearance of a road- or gravel bike with the versatility and usefulness of a commuter- or touring bike. In this regard I particularly like the concept of the hub drive motor, because when it is switched off, it is not noticeable at all, there is no additional resistance to overcome, no sprockets that unnecessarily need to be moved. Makes life easier for sure!
Depending on the situation and your needs, eSilex turns from a sporty- into a commuter bike that is fit to get you to the office daily and flattens the annoying last climb on your way back home.


XS (47) S (49) M (51) L (53) XL (56)
Seat tube (mm) 470 490 510 530 560
Top tube (mm) 525 540 555 570 585
Steering angle (°) 69,5° 70° 70,5° 71° 71,5°
Seat tube angle (°) 75° 75° 75° 75° 75°
Chainstays (mm) 431 431 431 431 431
BB drop (mm) 70 70 70 70 70
Steering tube (mm) 145 160 175 190 205
Fork length (mm) 400 400 400 400 400
Standover height (mm) 748 767 785 804 830
Wheelbase (mm) 1,032 1,044 1,055 1,066 1,076
Stack (mm) 565 581 597 613 629
Reach (mm) 374 384 395 406 416

Unlike other systems, that support exponentially or at least gradually, the x35+ motor does so very linearly. This makes you feel in control of the bike when setting off and encourages you to pedal yourself.
There is no acceleration effect, which I really liked when riding with Bosch’s Performance Line CX on Canyon’s Grail:ON, for example – up to 95 Nm of torque (!!!). It rather feels like standing on an escalator. This is among others because Mahle’s motor has no cadence sensor but calculates the torque via the hub’s rotation speed and the movement of the cassette sprocket which is a rather complex process. Ok, cool.

 You feel like you're standing on an escalator. 

How motor support works

Thanks to this economical motor control, the relatively small 250 Wh battery makes for a considerably range. Theoretically, the x35+ motor delivers a maximum power of 250 watts to the rear wheel – therefore the battery should last for roughly one hour on permanent support at the highest level.
Transferred to real life this means rides of several hours are no problem depending on speed and terrain; longer day trips may require a range extender, i.e., an additional battery mounted in the main frame that provides another 250 Wh.

No path to follow!

But enough of technical details – let’s see how the bike performs in real life. eSilex is a fun ride, whether off-road or on-road, but it certainly feels most at home on sandy roads or dirt tracks. On asphalt, I miss the agility of a classic road bike, but I’ve done so on any e-bike I’ve ridden so far.
I love road cycling among others because of the suffering uphill, the joy of speed downhill, the acceleration in sprints – in a nutshell: I am drawn to road bikes as they represent the essence of suffering. This doesn’t mean that suffering is impossible on an e-bike, but it is only half the fun. Furthermore, it is too big a temptation to switch on the motor as soon as the going gets tough.

Off-road, however, I am primarily looking for fun and relaxation. And eSilex provides plenty of it due to an agile, but not aggressive geometry and fine-tuned motor support, if needed.

Even on demanding terrain in the forest the bike performs well and rolls surprisingly patiently over rough trails and down technical descents. Monster gravel? No problem as long as things stay civilised. Rock gardens and root trails are no option however, the Maxxis Rambler tyres perform well, but cannot work magic.

I set the three support levels individually before going on a ride, i.e., the first level, green, supports with 33%, orange with 66% and red with 100%. More lightweight riders might do it differently, but when I switched on the motor, I always opted for full support – with a body weight of 85 kg I live by the motto: more is more!

I consider it handy that the eSilex may be turned into an (almost) perfect commuter bike for city rides during the week. Probably thoughtful engineers at Merida’s had the same idea and created an eSilex clone with eSpeeder 400 EQ: both bikes are basically identical, same frame, same geometry, but with one big difference: eSpeeder is more suitable for daily use, as it comes with mud guards and luggage rack already mounted as well as with a permanently installed light system. I like the eSpeeder’s single speed crankset better, but that’s a matter of taste.

Life is sweet!

And there is more good news – both eSilex and eSpeeder series set new standards in terms of affordability, because my test bike is available for an original price of € 2,699, even the top model eSilex +600 remains at € 2,899 well below € 3,000. eSpeeder 400 EQ costs even less at € 2,499.

Merida’s eSilex will take you to the Stone Age in a way, as “silex” is the archaeological term for flintstone and all things made from it. This way, Merida nicely refers to a time when flintstone was the most state-of-the-art thing you could get. eSilex indeed lives up to this comparison, as it certainly is a very versatile ride. This agile and lightweight e-bike performs well on forest paths, asphalt roads or in daily city traffic.

 I love a good ride like this, it's fun and doesn't cost much – this way anyone can afford some happiness! 

Hermann Leopoldi about Merida’s eSilex 400


Merida eSilex 400
Model year: 2021
Test duration: 2 Monate
Price: € 2,699 SRP
+ Fine-tuned overall package
+ Solid e-bike for less than 3,000 euros? Unbelievable ...
+ Silent and resistance-free riding thanks to hub drive motor
o Relaxed geometry
- Wheel change is tricky (installation width of hub drive motor)
- Control system needs getting used to
- iWoc switch makes top tube bags difficult to use
BB-Urteil: Go. Further. Believe.

In terms of quality there is nothing to complain about, even when it comes to the cheaper eSilex 400 – as usual Merida provides high manufacturing quality and well-matched components.
Merida’s eSilex proves that an e-bike does not necessarily need a monster motor to be fun. The concept of "gentle" motor support is just perfect for riders who want to boost their fitness, but still be prepared for all riding situations.
And – spoiler alert: This concept offers options that hint to what might be possible in hub drive motor development in the next few years …

Do I recommend the new Merida eSilex 400? The answer is: yes and no. If you want a very silent, sporty leisure bike, I can't think of any alternative in this price segment right away. If you'd rather have a high-torque off-road bike, you might be better off with models with Bosch Performance Line CX mid-motor – but these, of course, come with a price tag.