BBSxx Mid Drive Conversion

[JohnnyBBadd]

Hopefully the following might help anyone looking to make their own conversion using the Bafang BBSxx range. From my own experience, the process can be tricky to understand and, at times, both confusing and contradictory. After much research, and a lot of help from members within this forum, I chose the Specialized Rockhopper Sport (2017 model) - as a great basis for conversion. I chose the mid drive because of its torque, low down weight distribution and aesthetics. I use the bike as a daily commuter and as a 'weekend warrior' mountain bike - it does both jobs brilliantly. I have definitely benefited from the bike's hydraulic disc brakes and am considering the optional hydraulic brake sensors that are available for the kit.

The bottom bracket size states 73mm on the Rockhopper spec sheet, which I thought would mean that I wouldn't be able to use the locking nut. Whilst the bottom bracket itself is, indeed, 73mm wide, the bottom bracket 'shell' is only around 70mm and therefore accommodates the locking nut easily.

The locking nut fits! Note that you will need the longer hex bolts and extra washers to use as spacers. Eclipse Bikes supplied these for me...​

Also (another happy accident)! with this bike; the supplied Bafang chain ring sits at exactly the right space from the chain stay, so there is no need to worry about having to purchase another ring, or spacers.

Perfect!​

The chain hasn't come off once...

​

For the battery, I was recommended to Jimmy at INSAT International - a great recommendation as he makes the best quality and value e-bike batteries on planet Earth, and will give you sound advice regarding the best options for your use. Think about whether you want it mounted on the frame, (I eventually chose not to, although it fits fine), a rear carrier, or in a back-pack. Jimmy can even make a more compact battery to fit within a saddle mounted bag, if you supply the dimensions - Just put aside 1/2 hour, or so, he's very thorough!

Remember, a 500w, 750w, or 1000w motor is illegal to use on anything but private land, with the land owners expressed permission. If I were a retailer, I would refuse to give you any advice other than to fit a 250w motor. However, having taken a cursory look on the internet, I can find no examples of cases brought to court in the UK, nor examples of any prosecutions...Nevertheless, the potential risk is all yours.

If you want any advice with regard to installation, just ask - I'd be happy to help!

This should help with some of your installation questions:

 

[brightonebikes]

Nice little write up JohnnyBBrad, some really useful info. Here's an older bother. Many good times ahead me thinks. Enjoy.

Sent using this crappy tapatalk app. that has such poor functionality I can't even click 'like'!

 

[brightonebikes]

Regarding the electromagnetic brake sensors and fitting to Shimano BR-M315 levers, I've found this tricky to make work successfully, owing to the shape of the levers and how the pivot action works. If you do succeed, please post some photos

Sent using this crappy tapatalk app. that has such poor functionality I can't even click 'like'!

 

[JohnnyBBadd]

Hopefully the following might help anyone looking to make their own conversion using the Bafang BBSxx range. From my own experience, the process can be tricky to understand and, at times, both confusing and contradictory. After much research, and a lot of help from members within this forum, I chose the Specialized Rockhopper Sport (2017 model) - as a great basis for conversion. I chose the mid drive because of its torque, low down weight distribution and aesthetics. I use the bike as a daily commuter and as a 'weekend warrior' mountain bike - it does both jobs brilliantly. I have definitely benefited from the bike's hydraulic disc brakes and am considering the optional hydraulic brake sensors that are available for the kit.

The bottom bracket size states 73mm on the Rockhopper spec sheet, which I thought would mean that I wouldn't be able to use the locking nut. Whilst the bottom bracket itself is, indeed, 73mm wide, the bottom bracket 'shell' is only around 70mm and therefore accommodates the locking nut easily.

The locking nut fits! Note that you will need the longer hex bolts and extra washers to use as spacers. Eclipse Bikes supplied these for me...​

Also (another happy accident)! with this bike; the supplied Bafang chain ring sits at exactly the right space from the chain stay, so there is no need to worry about having to purchase another ring, or spacers.

Perfect!​

The chain hasn't come off once...

​

For the battery, I was recommended to Jimmy at INSAT International - a great recommendation as he makes the best quality and value e-bike batteries on planet Earth, and will give you sound advice regarding the best options for your use. Think about whether you want it mounted on the frame, (I eventually chose not to, although it fits fine), a rear carrier, or in a back-pack. Jimmy can even make a more compact battery to fit within a saddle mounted bag, if you supply the dimensions - Just put aside 1/2 hour, or so, he's very thorough!

Remember, a 500w, 750w, or 1000w motor is illegal to use on anything but private land, with the land owners expressed permission. If I were a retailer, I would refuse to give you any advice other than to fit a 250w motor. However, having taken a cursory look on the internet, I can find no examples of cases brought to court in the UK, nor examples of any prosecutions...Nevertheless, the potential risk is all yours.

If you want any advice with regard to installation, just ask - I'd be happy to help!

This should help with some of your installation questions:

 

[Gagsinio]

Hopefully the following might help anyone looking to make their own conversion using the Bafang BBSxx range. From my own experience, the process can be tricky to understand and, at times, both confusing and contradictory. After much research, and a lot of help from members within this forum, I chose the Specialized Rockhopper Sport (2017 model) - as a great basis for conversion. I chose the mid drive because of its torque, low down weight distribution and aesthetics. I use the bike as a daily commuter and as a 'weekend warrior' mountain bike - it does both jobs brilliantly. I have definitely benefited from the bike's hydraulic disc brakes and am considering the optional hydraulic brake sensors that are available for the kit.

The bottom bracket size states 73mm on the Rockhopper spec sheet, which I thought would mean that I wouldn't be able to use the locking nut. Whilst the bottom bracket itself is, indeed, 73mm wide, the bottom bracket 'shell' is only around 70mm and therefore accommodates the locking nut easily.

The locking nut fits! Note that you will need the longer hex bolts and extra washers to use as spacers. Eclipse Bikes supplied these for me...​

Also (another happy accident)! with this bike; the supplied Bafang chain ring sits at exactly the right space from the chain stay, so there is no need to worry about having to purchase another ring, or spacers.

Perfect!​

The chain hasn't come off once...

​

For the battery, I was recommended to Jimmy at INSAT International - a great recommendation as he makes the best quality and value e-bike batteries on planet Earth, and will give you sound advice regarding the best options for your use. Think about whether you want it mounted on the frame, (I eventually chose not to, although it fits fine), a rear carrier, or in a back-pack. Jimmy can even make a more compact battery to fit within a saddle mounted bag, if you supply the dimensions - Just put aside 1/2 hour, or so, he's very thorough!

Remember, a 500w, 750w, or 1000w motor is illegal to use on anything but private land, with the land owners expressed permission. If I were a retailer, I would refuse to give you any advice other than to fit a 250w motor. However, having taken a cursory look on the internet, I can find no examples of cases brought to court in the UK, nor examples of any prosecutions...Nevertheless, the potential risk is all yours.

If you want any advice with regard to installation, just ask - I'd be happy to help!

This should help with some of your installation questions:

 

[Gagsinio]

That's a nice looking bike and you seem to have avoided some of the worst issues Why did you decide against the Frame pack, was it a weight or strength issue?

 

[JohnnyBBadd]

That's a nice looking bike and you seem to have avoided some of the worst issues Why did you decide against the Frame pack, was it a weight or strength issue?

Weight really. I like to keep it off of the bike for when I have to man-handle it over styles, fences and walls. If I was just commuting with it, then yes, the frame mount battery would be fine.