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21 Flow

  • Commuter and Light Trail Riding


You’re an urban commuter who wants to zip through traffic on a comfortable ride. You admire Scandinavian inspired design. 

You appreciate a graceful step-through frame that allows you to easily, safely mount and dismount your e-bike anytime you want. 

You and Flow are going to get on so very fine. Inspired by San Francisco’s fogs, the Espin Flow e-bike comes in smoke gray and forest green.

Suggested for riders 5'2" - 6'4"

  • 500W Geared Hub Motor 

  • 30 - 50 Miles per Charge 

  • Class 2

Estimated Delivery: 1-2 weeks

Espin Guarantee


Motor Brand     

Motor Type 

Rear Mounted Geared Hub

Motor Nominal Output

500 watt nominal/800 peak output

Motor Torque

65 Nm

Battery Brand
Samsung Cells

Battery Voltage
48 volts

Battery Amp Hours
14 ah

Battery Watt Hours

Battery Chemistry

Battery Charge Time
6 hours

Riding Range Estimated Min
30 miles

Riding Range Estimated Max
50 miles

Display Type     
Espin color LCD

Speed, Battery, Assist Level (1-5), Odometer

Drive Mode     
12 magnet sealed cadence sensing pedal assist

Top Speed     
Class 2

Bike Components

Attachment Points

Rear Rack bosses, Fender Bosses


Zoom Dual Piston Hydraulic Disc Brake, Front/Rear w/180mm Rotor

Zoom levers with Integrated Motor Cutoff


Alloy Cranks 170 mm, 45T Chainring with Plastic Bash Guard


100mm Travel Hydraulic Lockout

Frame Size


Frame Type



S-Ride 8 speed 13-32T

Hand Grips



Zoom Alloy Flat Handlebar 25.4mm



Wellgo Aluminum Alloy Platform

Rack Capacity

55 lbs (25kg) 15" x 5"


Selle Royal Freeway


Zoom 30.4mm


S-Ride triggers


CST 27.5 x 2.10


55 lbs

Locking Removable Battery Pack & Fenders

Gives you the freedom to explore

21 Flow is a class 2, or low-speed throttle-assisted, electric bike that gives your daily commutes and cruises a smooth boost. Our fine-tuned Espin motor and controller that have undergone rigorous testing and QA is powerful and reliable. The Samsung 672 wh battery is fully integrated in the lower part of the frame for weight distribution and can take you as far as 50 miles per charge. 

Ride with comfort and safety with this low-impact, step-thru bike that also supports your posture as you soak in the scenery. Bon voyage!

Your safety matters

This step-thru bike was meant to work particularly well for urban commuters. It can easily maneuver city streets, and you can get on and off the bike quickly and easily to help keep you safe. 

Like the 21 Nesta, it’s great for shorter riders with a low step-thru frame. Also, it has 8 gears, a max speed of 20 mph and will work well on any terrain. So, you can ride the bike outside of the city as well.

20 mph

Top Speed

30 - 50 miles


Hop on and off with ease 

Riding a bike can help people stay fit and feel younger. It's also low impact, so it's pretty easy on the joints, especially on a step-thru bike.

Step-thru bikes allow for a more relaxed sitting posture due to the easier placement of cruiser-style handlebars as well as the often more forward placement of the pedals. This more natural sitting posture puts a lot less strain on the joints, and this makes it a popular choice for senior riders.


Standover Height

Ride with peace of mind

The 21 Flow features cruiser-style handlebars so you take a relaxed sitting posture when you ride about town and soak in the scenery. No need to be hunched over.


Battery Watt Hours

6 hours

Charge Time



Espin 21 Flow Size Chart

Suggested for riders 5'2" - 6'4"

1. Reach 17"

2. Handlebar Height 44"

3. Stand Over Height 19"

4. Total Length 70"

5. Minimum Saddle Height 32"

6. Maximum Saddle Height 41"

Total Weight Capacity 275 lbs

Financing Options

We’ve partnered with Klarna to provide you with easy payment options at checkout, so you can buy what you want, when you want.

Click here to learn more about the financing options.

Frequently Asked Questions

Click here to learn more about our Frequently Asked Questions

+ What's the difference between Espin's Flow and Sport eBikes?

The Flow is a European inspired design built for the urban commuters who wants to zip through traffic and ride comfortably. Elegant 17” step through frame that allows you to mount and dismount easily and safely anytime you want.

The Sport comes in a 17 inch diamond frame and is for riders looking for a more sporty and aggressive riding style.

+ How will the Flow's tire do in snow or a beach environment?

The Flow is meant for pavement and will not handle snow. For snow, try the Nesta or Nero.

+ Can I ride my Espin pedal-assist e-bike in the rain?

Yes, we have waterproofed all the wiring and electrical connections so it can withstand rain. Of course, one should not let the bike just completely soak in the rain if possible, but there is no need to worry about riding in rain.

+ What is an electric bike (e-bike) and what makes it different from a regular bike?

An electric bike is just like a regular bike, except for 4 main electrical components: the battery, motor, controller and display. Other than that, it will function and ride just like a normal bicycle. 

The Espin eBike is a pedal assist bike, which uses the motor to increase the power created when you pedal. So it rides and turns just like a regular bike, it just makes riding easier, especially uphill.

+ What is Espin made of?

Espin pedal-assist eBikes are made from 6061 aerospace grade aluminum alloy.

+ Can I assemble it myself?

Yes! The assembly takes less than 15 minutes and we even provide all the tools you need. If you run into any issues, you can follow along in the assembly video.

+ What maintenance is required?

Maintenance is exactly the same as a regular bike other than the four main electrical components: battery, motor, controller, display. You should do basic tune-ups on your bike after the first 100 miles. Regular tire pressure checking is important as you want to keep your tires inflated for maximum riding comfort. 

Other than that, the electrical components should require minimal maintenance and if any issues arise, please follow the instructions to diagnose the issue, which will be included in the user manual. If you are still unable to fix the problem, please submit a warranty claim and we will process your claim as soon as we can as we understand you want to get back on the road as quickly as possible.

Go for a spin with your 21 Flow  today

Customer Reviews

Based on 96 reviews
David McKenzie
My Flow 21 purchase

I had a few minor issues that were quickly resolved by Miguel. It’s a great bike. Rides well and looks great.

christopher allibone
Lynn loves her new Espin 21 Flow

Beautiful bike

David Baldus
So far so good

My first e bike. I'm getting familiar with how to use both the gears and pedal assist.
I'm pleased with the ride and looks of the bike.
I do need to have the rear brake checked. I assume it needs more fluid.

Susan DuBois

21 Flow

David Chambers
Great Bike

Perfect ebike for my wife. Great to have lights head light and tail light integrated with bike battery. Hand grips are comfortable and 5 speed power is great!

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