The Bafang motors that we stock are capable and suitable of converting over 90% of traditional bicycles on UK roads into electric bikes. Here, you will find general advice about what can and cannot be converted. It must be said that there is a very slim chance that your bike will not be compatible. If you would like to contact us for any further guidance at any point, please get in touch!
If your bikes frame is either manufactured from steel, aluminium alloy or titanium, the motor can safety be fitted providing the bottom bracket is adequate. Many carbon frames, however, will not be able to have the mid drive motor fitted. This is because some carbon frames won’t be able to take the required torque needed to lock the motor securely in place against the bottom bracket shell. The locking nut must be tightened sufficiently against the bottom bracket shell to ensure the motor cannot move and instead distribute power effectively. One a carbon frame, this tightening against the bottom bracket shell may crack the frame.
Before you order your kit, you must firstly determine the width of your bottom bracket shell. Bottom bracket shells are either 68mm, 73mm, 83mm, 86.5mm, 89.5mm, 92mm, 100mm, or 120mm. Most bikes will have either a 68mm or 73mm bottom bracket shell which is compatible with all our motors.
If your bottom bracket shell is over 83mm, you will require a larger sized Bafang BBSHD 750w or 1000w motor because these are the only motors which offer a longer axle, however, any motor above 250w isn’t road legal here in the UK, so please keep this in mind.
The mid-drive motors bottom bracket shaft has a diameter of 33.5mm and will fit comfortably in many 68 – 83mm bottom bracket shells.
Bottom Bracket Standards:
There are two basic categories in which a bottom bracket will fall under, either “threaded” or “press fit” bottom brackets.
Threaded bottom brackets use a shell with internal threads to hold threaded parts. The frame shell may be threaded directly at the shell, or there may be an insert installed that has internal threads. The non-drive side (left side) on the English standard is a right hand threading, tightening clockwise. The drive side (right side of the bike) uses a left hand thread, tightening counter clockwise. The shell inside diameter will be approximately 33.7mm. There are other less common threading standards such as ISIS Overdrive, Italian, French and Swiss.
Press-Fit Bottom Brackets use a simple bore with no internal threading. The bearing or bearing cup will be slightly larger than the bore of the frame and is pressed inside the shell. This creates an interference fit, also known as a press fit. The bottom bracket is held in by the pressure created by the interference.
More information on bottom bracket standards can be found online. Bike Radar® have produced a helpful guide which can be found by clicking here.
Threaded Bottom Bracket (External Notches):
If your bike has a bottom bracket with external notches and bearings, and looks similar to the above photo, the tool included in our kits may be compatible as long as the bottom bracket you have has 16 notches around the perimeter with an outer cup diameter of around 44mm. If the outer diameter of the bottom bracket is larger at 48.5mm, a tool similar to the Part Tool BBT-29 is required.
Threaded Bottom Bracket (Internal Notches):
If your bike has a bottom bracket similar to the picture above, you have a threaded bottom bracket which has internal notches for removal. This type is found on many square tapered spindles (not all), and requires an alternative tool for removal. A common tool used for this removal is either the Park Tool BBT-18, BBT-20 or BBT-22. Counting the number of splines will show which tool is required. This tool slots into the bottom bracket and with the help of a spanner, your bottom bracket will come free.
Cup and Cone Bottom Bracket:
These type of bottom brackets were a widely used standard at one time and are typically found on the older generation bikes. The removal of this type of bottom bracket requires two separate tools, an outer lock ring spanner and an adjustable cup spanner. To remove the outer lock ring, a hook spanner such as the Park Tool HCW-5 is required. Once this has been loosened and removed, you must remove the adjustable cup which can either require a pin spanner such as the Park Tool SPA-1 or a flat adjustable wrench such as the Park Tool HCW-4 or HCW-11. As these may often be found on the older style bikes, the bottom brackets may have corroded onto the frame, so a hard rubber mallet may be required to knock the bottom bracket free.
Press-Fit Bottom Bracket:
If your bikes bottom bracket has no tool markings for removal, or has no thread markings, the bottom bracket is a press-fit, pictured above. This type is found on many carbon frames and requires an alternative tool for removal. A common tool used to removal these kind of bottom brackets is the Park Tool BB3-90.3. The tool slides through the bottom bracket and the spayed end opens up. By hitting the other end with a hammer, this shall force out the bottom bracket.
Once you have determined which bottom bracket your bike has, if it is different to the removal tool included in the kit, you shall need to purchase this separately. The bottom bracket removal tool included in our kits cater for the most popular external bearing bottom bracket types. The tool fits bottom brackets with an outer diameter of 44mm and consists of 16 notches that securely engage with the 16 indentations on the perimeter of the bottom bracket cup. There is a great page published by Park Tool® to help identify what removal tool you may require. Please click here to see their bottom bracket tool selection. If you are still unsure about which bottom bracket you have, or cannot remove it, take your bike to your local bike shop and have them remove it for you.
Our kits are supplied with replacement E-Brake Levers which automatically cut the power to the motor whilst the brake lever is applied. Nowadays however, the majority of bikes that have cable brakes also have integrated gear shifters directly connected onto the brake lever. If this is the case, the E-Brake Levers shall not be suitable unless a separate gear shifter is purchased. If your bike has hydraulic brakes, the supplied E-Brake Levers included in the kit will also not be compatible.
Do not worry, the E-Brake Sensors that we stock eliminate these problems and are designed for these problematic situations. The E-Brake Sensor has two parts, one of which adheres onto the brake levers housing, and a small magnet which is applied onto the brake lever. This can sense when the lever is applied as the magnetic field shall be broken, in turn cutting the power to the motor.
Whilst we would always recommend having a guaranteed way to stop safely, it isn’t essential that you have E-Brakes. This is because the pedal assistance within the motor recognises when you are not pedalling and so stops the motor. Providing you do not pedal and brake at the same time, the motor will not become engaged, and so you can use regular brakes to stop.
There are many bike types available today including; road bikes, mountain bikes, hybrid bikes, commuter bikes, cyclocross bikes, tandems, recumbents, gravel bikes, cargo bikes, cruisers, folding bikes, chopper bikes, touring bikes, vintage bike, the list goes on.
The question is can my bike type be converted… To which the answer is most probably. Whilst some bikes may at first seem too difficult or impossible to convert, creativity helps hugely. For example, some small or step through frames may not be large enough to fit a battery on either the down tube or top tube, and so it seems the conversion won’t be possible, however, it would be possible to fit a pannier battery. Another example would be complex full suspension mountain bikes, where again it can be difficult the fit a battery within the frame. On these type of bikes, a pannier rack battery would be recommended as the off-road conditions may not support the battery as much as is required. A bag battery however in this scenario would be ideal, as the battery is completely hidden within your bag, and a magnetic switch can connect the battery to your bike behind the seat post.