Ariel Rider Kepler Review

Ariel Rider Kepler Review

Hi all, in this article we’ll be reviewing Ariel Rider’s Kepler, which is the very entrance of Ariel Rider to a new e-bikes class, a sign that they’ll be providing more powerful motors and longer range battery options.

Kepler is a 52V ebike with a 1000W motor capable of delivering up to 1800W of power, an unusual value for this segment. With its massive 1000 Wh battery, Kepler is surely a very exciting ebike.

Another distinctive feature of Kepler, before going into details, is that it has the most heavy duty rear rack I have ever seen. Even when I let my friend get on it, the rear rack was fully capable of carrying an adult. The most exciting part is that the motor also has no problem in handling this weight.

Now, let’s get into the details.

Let’s check the key specs of RadRover 6 Plus then get straight into our review.

Key Features
Motor1000W Brushless Geared Hub Motor 1800W Peak Power
Range70-plus mile range, claimed
Pedal Assist6 PAS levels, 12 magnet cadence sensor
DrivetrainShimano 7-speed with an Altus rear derailleur and Tourney shifter 
Battery52V 20ah battery
Frame6061 Aluminum alloy
TiresCST 20×4.0
BrakesTektro hydraulic disc brake with 180 mm rotor front and rear

Motor & Power

As a brand known for producing motors which provide high power and torque for a long time, Ariel Rider recently teamed up with Bafang Motors. And this was definitely the best Bafang motor I’ve ever used. It is a customized nominal 1000W motor, so it means you can get 1000W on a continuous basis and when needed, the motor can deliver up to 1800W of power. It also has a twist throttle, which is my favorite type as I am definitely not a big fan of thumb throttles. The motor is a bit noisy, but to a reasonable amount considering the RPM and power of the e-bike.

My speed test concluded that Kepler is the most powerful hub motor in this class that I have ever tested. I tested Kepler at different pedal assist levels as well as throttle only, all with fully charged batteries and on flat surfaces.

Ariel Rider Kepler’s speed at lowest pedal assist is 14 mph. The first 3 pedal assist level speed is similar to other e-bike’s in this class. But at high pedal assist level you definitely feel the difference and power of the bike. At the highest pedal assist level Kepler is able to reach 37 mph.

Now, the speed on throttle only. In this test I didn’t support the motor by pedaling and all the work is done solely by the motor. I was able to reach 35 mph on a flat surface without any difficulty. This is definitely the fastest and most powerful e-bike in this class. 

One major reason to buy e-bikes is to handle steep hills. For this test I did the usual hill climbing test in one of the steepest hills in this area which is 0.5 miles long and with 10% slope. So you will almost never experience such a climb with your e-bike. And if this e-bike can handle this hill, then most probably it will handle any hill you will encounter with your e-bike. 

I did this test with highest pedal assist support and throttle only. In pedal assist mode, it took 1 minute and 18 seconds to finish the test and my average speed was 22.8 mph. I could finish the hillclimb without having any difficulty and when finished, the test motor was still not even that hot!

When I climbed the same hill with throttle only my average speed was 17.7 mph and I finished the whole ride at 1 minute 41 seconds.

I even did a test ride of Kepler with a passenger sitting on the rear rack. And the rear rack seems to be a very heavy duty one. I was just curious how the bike motor handles two adults. To my surprise, with a passenger sitting on the back it can still reach 28-30 mph on flat terrain on throttle only. I think it can reach higher speeds but I was worried so after 30 mph I just didn’t want to go faster.


Ariel Rider Kepler has a 52V battery system and the only other e-bike to offer such a system in this class is Juiced Ripcurrent. It consists of a 52V 20ah battery which has 1040Wh battery capacity. I also tested range at different speeds of 10 mph, 15 mph, 20 and 25 mph. When fully charged, at 10 mph you can have 66 miles of range and at 25 mph on pedal assist you can ride Kepler for 48 miles. On throttle only at 32 mph I was able to make 41 miles of range. Sure if I ride slower with throttle the range can be longer. These values make Kepler the longest range among all other e-bikes in this class.

Kepler has a 3 amp charger and connector is a customized one which can handle high currents. So if you want you can later upgrade your charger to a 4 amp charger. The standard charger coming with the e-bike is a very compact and light charger and to my surprise it doesn’t warm up. It is the same charger I see in Radrover but seems to be a faster version. 

One thing I like and dislike about this e-bike is battery design. They didn’t have a fully integrated battery like the one Aventon has and I love such battery design. When I talked with Ariel RIder they told me the main reason was the battery capacity. Such integrated batteries can’t handle this 52V 20ah battery as there isn’t enough room inside. Also another reason they choose this design is the convenience of pulling the battery. As most such e-bike riders pull out the battery and it is a little bit more inconvenient to do it several times each day. But still, I love the looks of an integrated battery. So this is my message to Ariel Rider: I hope they have a fully integrated battery model in the future.


The display is a very high end one and I am pretty sure it is the same that I see on Aventon e-bikes. It is large enough to read every info you need and even on a sunny day I had no difficulty in reading it. I totally love this display and the resolution is very high end. You can change the speed limit using the display and I definitely advise you to do so to enjoy this e-bike. It is, along with Aventon, the best display I see in this class.

Braking Performance & Drivetrain

Ariel Rider is using Tektro hydraulic disc brakes with 180 mm front and rear rotors, and the brakes have integrated motor inhibitors. Tektro is my favorite brake when it comes to e-bike brakes. Sure Shimano or Magura have higher end brakes but they design their brakes according to the mid-drive system and they lack motor inhibitors. So even if Tektro isn’t the greatest brake of the world, it is my favorite.

I did the stopping test at 10, 15 and 20 mph speeds. At 10 mph stopping distance came 5’6”, where at 20 mph speed stopping distance is 10’6”. These numbers are not different from what I expected as Tektro hydraulic brakes are really very reliable.

Drivetrain of Kepler is Shimano Altus 7 speed. It isn’t one of the greatest drivetrains but it’s definitely better than Shimano Tourney. To be honest, with a dual motor set-up you won’t need to use your drivetrain but it is still handy to have if you are going to do some hillclimbing. 

It has a default derailleur protector which is a nice touch that protects your derailleur during transportation and also in case your e-bike drops.

Comfort & Utility

Ariel Rider Kepler has CST 26×4.0 puncture proof fat tires. I love fat tires as the large volume low pressure tires absorb shocks which make your ride more comfortable. Also large tires provide more balance and control, which gives a beginner rider the confidence to seek more adventure.

In addition to that Kepler has Zoom Suspension which has adjustment and lockout and has 80 mm of travel. This kind of suspension is more than enough for most riders and stanchions on the fork are 32 mm which is wider than most forks in the market. It is very responsive and comfortable to ride this e-bike. 

Saddle is comfortable but still not the best saddle I see in the market. I love the saddles of Pedego which are wide and very comfy. But for these e-bikes it is difficult to offer a one-type-fits-all saddle. They offer a hybrid saddle which is sporty but also a little bit comfortable. I still prefer to have a larger saddle for such e-bike.

Handlebar grips are ergo types which have a resting part. During long rides you will totally appreciate this feature.

In general, Kepler is a very comfortable electric bike. If you want to improve your comfort you can upgrade to a suspension seat post which will make your ride even more comfortable.

In terms of utility, this e-bike offers more cargo space and functions compared to other e-bikes.  The rear rack is very thick and large in size. I am pretty much sure it can handle weights up to 130 lbs without an issue. I tested this rear rack with my friend sitting on it as I mentioned in the beginning of this article, and we had no problem.  

You can also attach a large basket and even in that time it has space for your kid to sit on the back. And the rear rack comes standard with the e-bike. I really love the builty quality of this rear rack. I can even call this e-bike a semi-cargo electric bike. 

Price & Value

Kepler’s retail price is $1,999 but at the moment of launch Ariel Rider offers a $200 discount which makes this e-bike a great value e-bike. Compared to other e-bikes in this class such as Radrover, Himiway or Aventon, Ariel Rider offers better brakes, larger battery, more powerful motor and higher spec rear rack and still offers this e-bike at $200 discount. Even with $1,999 full price this e-bike is still a great deal.

One thing I can advise you is to change your headlight to a better one if you buy this e-bike as it isn’t one of the best headlights in this class. But this upgrade will cost you at most $35 and your upgraded light will be better than any other e-bikes’ light in this class.

One last word 

Ariel Rider Kepler is a feature rich, very powerful and a very long range e-bike which offers great value. They address issues people are facing with current e-bikes such as limited hill climbing skills of other e-bikes or limited range and offer a great e-bike. Also Kepler can be used as a cargo electric bike because of it’s rear rack. I really loved this rear rack as this will make your e-bike a total car replacement. It is a great electric bike and if you are looking for an e-bike in this class you should definitely consider Ariel Rider Kepler.  

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