- A classically styled city bicycle with BionX electric drive system, you get torque sensing pedal assist, four levels of regeneration and variable speed trigger throttle
- Available in two frame sizes for improved fit, beautiful paint-matched minimalist chain cover and chrome accessories (alloy fenders, cranks, seat post and steel bars)
- Mechanical disc brakes with tool-free adjustable pads, sturdy alloy chain guide reduces drops, steel frame and fork minimize vibration, reflective tires and integrated rear light
- Rear-heavy design with some of the weight high up vs. low and centered, throttle won't activate until the bicycle is moving ~2 mph for safety, more exposed wires
The D8 is a diamond frame (high-step), eight-speed, European-inspired city ebike made by Public. I got to study and test ride it at an exclusive retail outlet in Santa Monica California for this review… and in the process, learned a little bit about the founder. Rob Forbes launched and sold a furniture company called Design Within Reach before creating Public Bikes in 2010. It sounds like most of their business is done online but there are a handful of outlets like the one I visited and the employees there told me that one of the most popular and unique accessories selling right now is an adjustable leather wine bottle holder that hangs down below the top tube of bikes, perfect for picnics! So the company is more than just a bicycle seller, they peddle lifestyle goods that go along with bikes as well. And with electric bicycles still being relatively new and unique in the USA, it was great to see the D8 in person and have an opportunity to test ride it. I’m sure it’s a head turner for many patrons who notice the additional silver accents and wires compared to the D8i non-electric model. In so many ways, this is a bicycle first and foremost. The drive system has been added on, but it’s one of the higher quality offerings in the space with reliable operation and quiet, smooth power delivery.
Driving the bike is a time-tested BionX gearless hub motor operating at 350 watts nominal. It’s larger and heavier than a geared equivalent but performs without the noise and internal friction of plastic and metal gears. In the industry, I’ver heard e-bike shops refer to gearless motors as being “bulletproof” but that doesn’t make them perfect. You get a little bit of cogging drag when the bike is being ridden without power. That is, large magnets inside the hub repel electromagnetic stater panels and slow it down. It’s not a lot, but you can notice it if you lift the bike and spin the rear wheel. But that same drag can be turned into an advantage if the bike is powered on and you activate the left brake or arrow down to one of four “regeneration” modes turning the hub into an electric generator that puts power back into the pack. The motor is really quite powerful when operated at the higher levels of assist or with the trigger throttle compressed. As someone who rides a wide range of electric bicycle products, I am always delighted by the BionX systems and Go SwissDrive systems. To me, these two brands are leaders in the space for this particular approach to motor design. And with the BionX hub, you get a torque sensor built right into the motor vs. having a separate piece mounted inside or near the bottom bracket. It’s clean, reliable and makes bike service easier for shops.
Powering the motor, backlit display panel and integrated rear light is a 48 volt 8.8 amp hour battery pack. You can charge it on or off the bike and it locks securely with a metal core that you push in as the pack is slid all the way into the carry rack (you don’t need a key to lock it on). This mounting choice offers a mix of benefits and drawbacks because it frees up the main section of the frame for easier lifting, mounting on car or bus racks and adding bottle cages or accessories like folding locks or mini pumps… but it also adds to the already rear-heavy design of the bike. Remember, there’s a nine-pound motor spoked into the rear wheel. So now you’ve got eight more pounds mounted high up, taking away some of the carrying capacity of the rack and creating a potential for frame flex and hazardous tipping when parked. By opting for the universal rear-rack battery design, Public was probably able to save money and keep the price of their D8 Electric model down while simultaneously recycling it for the Mixte style M8 model. And you’ll definitely be able to find replacements for this battery easier than if it was a custom downtube style.
Operating the bike is pretty simple once the battery has been charged and mounted into the rack. Just press the top right button of the display panel then arrow up or down to select a range of drive modes. Before I dig in much further, I want to emphasize that this display panel is removable… so you can prevent tampering, vandalism, and weather-wear if you care to take it off when parking in public locations. Okay, so you’ve got no-assist in the middle and four levels of regen if you press the minus button on the control ring near the left grip as well as four levels of assist if you press the plus button. It’s very simple to understand and easy to execute, even without taking your left hand off the grip while riding. At any time when riding over ~2 mph, you can override assist by pressing in on the little red trigger. This gives you a range of power, all the way up to maximum, for a zip of support. I tend to ride with lower levels of assist to maximize range and then burst forward with the throttle to conquer a hill, pass slower riders or catch up with friends. All in all, this is a wonderful display panel and control pad combination. Newer and more expensive BionX systems have iterated on the design to make the ring selector stand-alone. They have also introduced color displays with larger readouts… but this classic design blends in nicely and again keeps the price within reach.
I was drawn to the Public D8 Electric based on its charming good looks and reminded why I like BionX products so much after a short test ride around Santa Monica. The good weather, friendly cyclists, and helpful staff didn’t hurt… but for those who can’t make it to a shop like this, they do offer a “ready to ride” complete build for $135 additional so you can receive a bike and start enjoying almost immediately. This product offers a solid two-year warranty with unique 30-day money back guarantee if you decide it’s not a good fit. One area that may require some customization is if you plan to pull a trailer (for children, pets or cargo). The BionX axle is oversized for increased strength and this means the standard Burley hitch won’t work without modification. And because the bike uses fancy disc brakes vs. linear-pull brakes, the rear triangle is partially blocked by the rotor mounts. You may also want to purchase a headlight if you ride in the early morning or late evening or commute year-round and end up in the dark as daylight savings time kicks in. I enjoyed the relaxed body position, comfortable Steel frame and plush touch points on the D8 and appreciate the two frame sizes on offer. It’s not the most high-tech purpose-built product on the market but it offers a lot of charm for a reasonable price.
- Public has a limited number of dealers (one of which is located in Santa Monica where I filmed the video review above) but they also sell online and ship their bikes “ready to ride” with easy setup for $135 extra so you don’t need to be an expert mechanic to start riding
- The D in D8 stands for Diamond, and while this frame may be too high for some riders to stand over, it doesn’t flex as much as the step-thru mixte M8 model
- Great commuter accessories come standard with the D8 electric including alloy fenders, chain guide, a rear rack, an integrated rear light (built into the battery pack), reflective tires and two pairs of bottle cage bosses for liquids or adding a folding lock or mini pump, consider adding an aftermarket rechargeable headlight like this to complete the bike
- The motor is extremely smooth and quiet but offers impressive power and torque for a gearless hub, it doesn’t interfere with the eight-speed drivetrain in terms of shifting,
the fenders didn’t rattle a lot during my test rides
- The geometry is more upright and comfortable than some other city bikes (three riser stacks and a low-rise handlebar) and the plush saddle, faux leather grips and steel fork felt good even without suspension, you could always replace the seat post with a 27.2 mm suspension seat post like this
- Steel tends to be very sturdy and offers some vibration dampening qualities that a lot of city cyclists appreciate, the D8 has a Steel frame and fork that ride well and can handle the added weight and forces of the motor
- Mechanical disc brakes aren’t as powerful or smooth as hydraulic but the Avid BB7 model has a tool-free adjuster ring on each caliper housing so you can dial them in yourself over time as you ride
- The rims have reinforcement eyelets to improve strength and durability, the rear spokes are thicker than normal to support the motor power and weight
- Available in two frame sizes for a more comfortable fit, very important here with the high-step model which has large 700c (~28″) wheels
- Given the heavier battery pack, it’s important that you can remove it for transport or convenient charging, the display panel is also removable
- There’s a pair of bosses on the underside of the seat stays in the back and apparently this is for adding a cafe lock “frame lock” like this if you want
- In addition to their solid two-year comprehensive warranty, Public also offers a 30-day money back guarantee which is reassuring if you’re purchasing online
- Unfortunately, it appears that this bike is not kid-trailer compatible because the rear axle is thicker than normal and the triangle near the dropout isn’t open due to disc brakes… if you want to use a child trailer you may have to engineer a custom adapter
- With both the motor and battery pack being positioned at the rear of the bike,
and being fairly heavy and high up, the bike isn’t as stable or nimble as those with mid-drive systems and mid-mount batteries… but you do get two pairs of bottle cage bosses!
- Since the rear rack is already supporting an eight-pound battery, you can’t load it up with as much additional gear (I’m estimating just 20 or 30 more lbs vs. 55 lbs on a lot of battery-free racks)
- I love that the Public electric bikes with BionX offer variable speed throttle in addition to pedal assist but you have to get the bike moving a couple of miles per hour before it activates, this is a safety feature
- The rear wheel doesn’t freewheel as efficiently as the front because the motor introduces cogging drag… but this enables regeneration modes and regen braking which is cool
- This electric bike isn’t as purpose-built as some of the more expensive ones hitting the market now, you can see the cables run along the frame externally and the BionX battery mounts to a bolt-on rack vs. being integrated
- It appears that only the left brake lever activates regeneration mode, it would be nice if both had this feature