- One of the only mid-drive electric bike conversion kits around, 8Fun is an established brand
- Offers both pedal assist and throttle mode configurations, great LCD screen with lots of options
- Not sophisticated enough to sense when shifting gears and let up, may wear chain and cassette faster
- Keeps weight low and center on bike, makes fixing wheels and flats easier than hub motors
$0 (0 €)$18,000 (16,920 €)
0 lbs (0 kg)220 lbs (100 kg)
0 mph (0.0 km/hr)50 mph (80.5 km/hr)
0 watt3,000 watt
0 in (0.00 cm)22 in (55.88 cm)
0 Newton meters250 Nm
The 8Fun or “Bafang” BBS02 electric bike kit consists of a 750 watt mid-drive motor, chain ring, cranks and LCD screen with button attachment. It’s designed to mount at the bottom bracket of a bicycle (replacing the standard ring and cranks) and pull the chain to propel the bike and rider forward. Before we get too far here, I realize there may be some confusion about the brand name… The full name is Suzhou Bafang Diandonchi Gongsi and this translates to Suzhou, 8 directions electric motor company (Suzhou is the town name). The “8 directions” part means “every direction” which is roughly equivalent to “Universal Motor” so altogether that’s City of Suzhou Universal Motor Company. Their marketing department came up with 8Fun which is short and catchy in English. In America, the motor is labeled as 8Fun but the LCD display still says Bafang. The company is well known for mass producing mid-level geared hub motors. What I love about this kit is that it’s one of the only mid-drive ebike kits anywhere and can be used on all types of setups including recumbent, cargo, road and mountain bikes (with bottom brackets between 68mm and 73mm). Unfortunately, there are physical constraints that limit its use on fat-tire bikes given the width of their bottom brackets at 100mm.
The BBS02 motor is a 750 watt geared design (as powerful as is legal in the USA) located in the black canister that sits just below the bottom bracket when attached (see picture below). It’s relatively quiet and leverages the rear cassette for improved climbing or speed depending on the gear you’re in. As with other centerdrive electric bike systems (like those from Bosch or Panasonic) this thing is fairly efficient if used properly. For example, if you start from rest and are in a high (hard / fast) gear you’ll strain the motor and eat through your battery quickly but if you start in a low gear and shift up as you gain speed (just like a manual transmission car) you’ll extend your range and get more torque. Because the BBS02 completely replaces the bottom bracket, cranks and chain ring you will only have one gear in the front after installing this kit. This means if you had a 21 speed before with 7 cogs in the rear cassette and 3 rings on the front you will now only have a 7 speed bike.
The battery setup with these 8Fun middrive kits is variable because they don’t come standard with a battery. You can work with a shop to choose one that will mount easily to your frame (either as a rear rack or downtube design) and get the size you need for power or distance. For the 750 watt motor setup shown here I was using a 48 volt 10 amp hour pack with longer lasting Lithium-ion cells and we just put it in the panniers hanging on the rear rack of the KMX recumbent trike. Just make sure the pack you choose is compatible with the system so you don’t have to manually cut and adapt wires. Depending on the shop you work with they may be able to configure the kit for you, my review was done with help from Long Island Electric Bikes that had several kits installed on different bikes by Surly and KMX.
Considering how integrated this kit looks it’s actually not that difficult to install. You will need a crank puller and spanner wrench and worst case your local bike shop could help. One of the nice parts about a mid-drive is that it leaves the front and rear wheels, cassette and derailleur alone. This reduces unsprung weight, keeps the bike balanced and make truing wheels and fixing flats much easier. I love that the kit works with pedal assist as well as throttle and the LCD display and break-out button interface is beautiful, backlit and intuitive. There’s a power button, a plus and a minus symbol that let you choose different levels of assist or navigate menus. You can see your speed, trip distance, battery level and get into wheel size settings, readout preferences, levels of assist and more. The display isn’t easily removable but it does swivel if you take one of the screws out on the back which is useful if you’re mounting this on a vertical bar (like on a recumbent) vs. a standard straight bar.
This is absolutely one of my favorite electric bike kits because it’s so versatile, well balanced and powerful. The price isn’t bad at all and if you’re willing to screw around a bit with the installation this could transform your bike into something really unique. Compared with purpose built centerdrive systems this one doesn’t have the ability to sense when you shift gears so that could lead to some grinding and wear the chain and cassette down faster… the key is to learn how to work with the system and shift when the bike already has some forward momentum vs. when it’s really pulling the chain. 8Fun has created something special with this kit and opened all kinds of new ebike possibilities that just wouldn’t work with hub motors. I’m thinking pedicab drivers could have a blast with this and as you can see from the review of this and the less expensive, less powerful BBS01 it also works great with cargo bikes.
- Can be operated above 20 miles per hour depending on wheel size and bike setup
- Offers both pedal assist and throttle mode for different styles of riding
- Leverages rear cassette for improved climbing or high speed riding, more efficient than a hub motor
- Keeps weight low and center on bike, reduces unsprung weight as compared with a hub motor
- Mid-drive electric bikes are easier to service (wheels and tires are easier to get at)
- 8Fun (Bafang) is a well established, trusted hardware supplier in China with solid track record
- Kit is compatible with a range of bottom bracket sizes (68mm to 73mm) but unfortunately not super wide 100mm fat-tire bikes
- Display is back lit, has a nice break out button console and lets you change lots of settings like number of pedal assist levels, speed readout and wheel size
- Not smart enough to detect gear changing and therefore does not let off which can mash gears
- A bit louder than most gearless hub motors I’ve tested, stands out on bike (not very stealth)
- Have to install yourself or work with a shop, not the hardest kit I’ve worked with
- Cadence sensing pedal assist isn’t as smooth as torque, batteries are sold separately from kit
- Gear range limited by single front ring, could increase gears by using a dual drive setup in the rear