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Hello and welcome my Bafang BBS02 review. The information in this article is based on my own personal experience installing over one hundred of these units during a three year period. I really like the Bafang and it’s an excellent motor, but like all things electric there are a multitude of gremlins that rear their head from time to time – in this post I will go over the good, the bad and the ugly!
- Great performance – best bang for your buck!
- Smooth and quiet motor
- Plug and play
- Good parts availability
- Easy to service and maintain
- Performance can be fine-tuned using the optional USB lead and software
- Controller failure
- Not 100% waterproof
- Increased wear on drivetrain
- Limited comparability – will only fit 68-73mm BSA bottom brakets
- Not road legal in some countries
The Bafang BBS02 is available in three different configurations: 36v 500w / 48v 500w and 48v 750w. The 750w version is the most popular as it offers the most bang for your buck! The motor itself is physically the same as the lower powered BBS01 250w / 350w, the only difference being the internals and controller. The installation criteria is the same as the other Bafang units for the classic 68mm-73mm bottom bracket fitment.
Is the Bafang BBS02B compatible with my bike?
The Bafang BBS02B is designed to be compatible with bikes that use a BSA threaded bottom bracket. These measure 68mm-73mm across the frame and have an internal diameter of approximately 33.5mm. If your bike has a pressfit (see below) or other type of BB, then I would seriously consider a compatible donor bike, as it will make installation a lot more straightforward.
Pressfit bottom bracket
As I have said above, I would personally not try to install the BBS02B on a bike with a pressfit bottom bracket. Although, in some cases this may be possible with a bit of ingenuity. A normal reducer shim may not be sufficient as it’s unlikely there would be enough clearance between the motor axle and housing (to clear the BB shell). You would need to machine an eccentric shim for this to be possible.
Boost rear hub spacing
A lot of modern mountain bikes have boost rear hub spacing (148mm) – the problem with this, is the angle of the chainstays are greater and can make installation of the motor difficult, if no impossible.
⚠Legal Information – is the BBS02B legal in my country?
If you are not familiar with e-bike law, in your country, it is worth checking beforehand. The Bafang BBS02 750w is legal in the US, but not road legal in the UK, EU or Australia, as the power output is rated at between 500w-750w. Peak power is substantially higher – up to 1470w on the 48v 750w model with a 52v battery fitted. If you are in the UK and planning on using this on private land, that is absolutely fine, but if you are going to use it on public roads then you should be aware of the potential legal implications first. Please read this post on UK/EU electric bike law.
What’s included in the Bafang BBS02B kit?
- The motor unit with integrated controller
- LCD Display
- Wiring loom
- Inner and outer lock-nuts
- Plastic Chain-guard
- Thumb throttle
- Brake levers with cut-off sensors (only compatible with cable brakes)
- Speed sensor and wheel magnet
- A bag of various Allen bolts and screws
Is the BBS02B easy or difficult to install?
Installation of this motor is the same as other mid drive motors. If you’re looking for a nice and easy conversion to do yourself, but you have little or no experience with bicycle mechanics, you should be warned that the installation can be quite challenging! See my guide on how to install a Bafang BBS02. The installation will need to be carried out by someone who is fairly competent. Removing the bottom bracket on your bike can be a right pain, and you will require a lot of patience!
Motor Technical Data
This electric motor produces considerably more torque than its smaller siblings (up to 120N.m), I have listed the peak power output for all the motor and battery configurations below:
|BBS02 500w 36v||36v (42.2v x 25A)||1055w
|BBS02 500w 48v||48v (54.4v x 18A)||864w|
|BBS02 500w 48v||52v (58.8v x 18A)||1058w|
|BBS02 750w 48v||48v (54.4v x 25A)||1200w|
|BBS02 750w 48v||52v (58.8v x 25A)||1470w|
I have listed the power output to include the 52v battery option, as this is quite popular. Although, I would exercise caution when using a 52v battery with the BBS02, due to reliability issues (please see below).
Like all the other BBS motors, the BBS02 uses an internal cadence sensor, and gives electric assist based on pedalling rpm. The pedal assist is very responsive, and can be fine-tuned using the 9 power levels available – update: It seems that most of the DP-C18 displays being shipped from China only allow for 5 levels of assist. If you require the full 9 levels go for the P850c display.
The motor kit is supplied with a thumb throttle, but I would exercise caution when using this. Heat dissipation is not as good on the BBS02 as it is with the BBSHD and even the latest ‘B’ version of the controller (with the upgraded INRFB3077 MOSFETs) can be prone to premature failure when using a throttle inappropriately.
If you need to use the throttle regularly, it would be worth changing the throttle ‘start current’ settings in the controller firmware (you will need a compatible USB lead and software).
It is crucial to be in a low gear on steep hill climbs or starts, as subjecting the motor to unnecessary load can cause the controller to blow.
Personally, I am not a big fan of these throttles. They are not particularly good for modulating the power, and function more like an on/off switch, although reprogramming the controller can make the throttle more user-friendly.
As with all the other Bafang models, the controller firmware settings can be changed with a USB programming cable and software (which you can download for free here). If you are doing this for the first time you should exercise caution and do your homework first. A good source of information on Bafang programming can be found on this excellent thread on Endless Sphere.
This kit is available with either a 44t, 46t or 48t steel chainring. If you are climbing lots of steep hills, I would definitely recommend an aftermarket chainring of around 36t .
One thing you will have to be aware of, if you do fit a smaller front chainring, the substantially lower gearing can make the bike prone to power wheelies, especially when hitting full throttle in a low gear on a steep hill start.
If you want to fit the brake levers with cut-off sensors, then bare in mind that these are only suitable for cable operated brakes. I would only recommend installing this kit on a bike with decent hydraulic brakes. Because this motor is so powerful, I would recommend the hydraulic brake cut off sensors or completely new hydraulic brakes with the sensors already built in.
Potential reliability issues
I have installed more BBS02 750w motors than any other (in excess of seventy units) and I have had a high rate of controller failure (17%). Whether this is down to the way the bikes are being ridden or the MOSFETs in the controller simply can’t handle the voltage and current, it is hard to say for sure. But there does appear to be a correlation between using 52v batteries and controller failure.
UPDATE: Through 2020 up to the middle of 2021 I haven’t had any reported issues with BBS02B’s I’ve installed.
The 36v and 48v 500w version seems to be the most reliable, to date I have only had one controller failure on this model. If you do experience failure (outside of warranty) replacement 750w Bafang controllers can be sourced online.
Can I use a 52v battery with the BBS02B?
A 52v battery when fully charged is at 58.8v, this is very close to the motor controller’s maximum operating voltage of 60v. I would personally stick with a 48v battery which is 54.4v fully charged. I have never had any issues with the motors that used 48v batteries. If you would still prefer to fit a 52v battery, then it would be worth buying a spare motor controller.
Having said that, I used a 52v Bafang BBS02 for a year and covered nearly 2000 miles, and I never had any issues – I later sold the bike, and it is still running well to this day!
The motor also uses a nylon primary gear, that can degrade over time. Replacements are easy enough to find, and there are plenty of good tutorials on YouTube for stripping this motor down.
Things to consider
- For the 500w and 750w 48v models, I would personally stick with a 48v battery, as the power gained by using a 52v battery is minimal, and in my opinion is not worth the risk.
- You will need a Bafang lock-ring spanner – the BBS02 will sometimes come loose due to the torque of the motor and may need periodic tightening.
- The speed sensor can be easily knocked out of alignment with the wheel magnet – this will throw up an error code and pedal assist will stop working.
- Some of the colour displays can be problematic – I find the black and white C965 display to be the most reliable, although the latest DP-C18 colour display seems to be pretty good (although most of these displays only allow for 5 levels of pedal assist).
- I would definitely recommend fitting a Bafang gearshift sensor, with between 500w – 1470w going to the rear wheel, you will drastically shorten the service life of your rear derailleur, cassette and chain.
- A heavy-duty chain is definitely recommended – there is a lot of torque going to the back wheel.
- If you are planning on keeping the bike long term, it may be worth stocking up on some spare parts. It is always useful to have a spare controller and a nylon primary gear.
A demonstration of the gearshift sensor working, on a BBSHD powered bike
Riding a Bafang BBS02B powered Electric Bike
All of these motors are quiet and smooth running, I have ridden all three versions, and in my opinion, there isn’t a massive amount of difference between them in the lower power levels, it is only in the higher levels you really notice the extra power of the 750w version.
The BBS02 is guaranteed to put a smile on your face – the days of being intimidated by steep hills are a thing of the past!
There is no doubt that in full power mode the 750w version is very quick, and a lot of fun to ride. Power-wise, there really isn’t a lot between the BBS02 and the BBSHD, although the latter has a lot more grunt, and the motor and controller can handle the extra power for a prolonged amount of time, whereas the smaller motor can become unreliable when subjected to constant hard off-road use.
As long as you are aware of this motor’s limitations, it is a fantastic piece of kit. If you constantly use it in full power mode, and use the throttle a lot, then it will inevitably let you down. I would advise you to purchase a spare controller or otherwise it may be worth spending the extra money and going for a Bafang BBSHD 1000w.
Install this kit on a decent bike, with good brakes and suspension and you will have a great high performance e-bike that is guaranteed to put a smile on your face!
I hope I haven’t put you off with this review, as I really believe this is a great electric bike conversion kit. As long as you can accept the potential long-term maintenance that will inevitably need to be carried out, it is well worth the money.
Where to buy the Bafang BBS02B
The Bafang BBS02B 750w is the best selling mid-drive e-bike conversion kit in the world, and is easily available in most countries. The cheapest place to buy is usually Aliexpress. Although, some people find the returns process can be difficult. If you’re concerned about potential problems and want peace of mind, then I’d be inclined to try Amazon or eBay. You will pay more, but returning a faulty motor is usually more straightforward. Below I’ve provided links to the Bafang motor sellers with good feedback in most regions.
|Amazon (various locales)|
|Banggood (EU Shipping)|
Thanks for reading and If you have any questions about the Bafang BBS02B, please feel free to leave a comment below – I check this at least once a day and usually answer questions within 24hrs.