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Thinking of adding a Bafang mid drive to your Belt Drive bike?

More and more customers have been asking about the feasibility of using a Bafang mid drive on their belt drive bike lately. So I have been doing a lot of research on this topic and will present my findings in the post. First let me point out that I am not a bike expert and since there are so many brands and models of bikes out there, you will need to do some research on your own to insure the best possible outcome to converting your bike. With that said let’s get into it.

The chart below is based on the Gates Carbon Drive belt system

Since Gates seems to be the only viable game in town, they are naturally the system we will be talking about. Also, in order to use the Gates drive pulleys, you will need chain ring adapters to be the interface from the Bafang to the Gates bolt on pulleys. I have chosen the California Ebike BA104, BA130 (used on BBS01/02/03) and the HD130 (used on the BBSHD 68mm and 100mm bottom brackets) adapters to calculate offset compatibility. There are other factors that you will need to consider and I will go into that further down in this post.

Why not just build “Special” offset pulleys?

We wanted to build special offset pulleys to help accommodate more brands but Gates Rubber has patented their pulley geometry and will not allow 3rd parties to produce pulleys. They also will not make specials according to their engineering department.  So, in our opinion, Rohloff is probably the only consideration for a successful belt drive system. We had hoped to find a solution for the Nuvinci  but at 12.2mm and 14.2mm offset misalignment, we felt there is no way at this time to make them work.

What else is there to consider?

I will list here some of the more obvious things to look at.

Many customers wanted to use the beautifully engineered Tout Terrain belt drive bike. The Bafang can’t be fitted to  this type of bottom bracket.

Other considerations

See the above. Gates ask you to check if your sprocket will clear the chainstay once mounted? Before you make that determination see how your Bafang mid drive will fit up.

The above is a ruff sketch of the BBS01/02/03 mid drive assembly areas for consideration. Will the final gear housing (113mm diameter) stay clear of the chainstay when mounted up against the 68mm bottom bracket?

Or on the BBSHD. Answer the same question but now the housing is 132mm diameter.

We will add more content to this subject as it becomes available but we felt that our customers should know what to look for when considering a belt drive system. Belt drives are fantastic when mounted with proper alignment but marrying a Bafang mid drive to the belt drive bike is a challenge unless you do your homework.

I would love to hear from those of you who are able to make successful installations. Tell us the make and model bike that you use and send some photos.

 

14 thoughts on “Thinking of adding a Bafang mid drive to your Belt Drive bike?

  1. great article

  2. Hi Doug – great article – I am looking to convert my rohloff/gates drive commuter to a Bafang mid-drive.

    I have an eccentric bottom bracket and vertical dropouts – if I change to Bafang, is belt tensioning possible?

    Any other tips?

    cheers!

    1. Adam, I don’t see any way to tension the chain with what you describe unless you can add a chain tensioner.

  3. AM I understanding this right that one would need to but spacers on the adaptor to offset the Gates “chainring” back towards to the centerline?

    I have a civia Bryant with alfine 8 IGH. It has straight dropouts chain tensioner and a split stay. Seems possible to do a BBS02 , i just don’t know what to order.

    1. We do not see any way to use a Gates drive with the Shimano IGHs short of modifying the bike frame/BB to correct the belt line.

  4. Great article thank you. I am currently considering purchasing a Ghost Square Urban 6 (Alfine 8 belt drive )and adding BBSO2 mid drive.

    Your May 26 comments seems really clear this is a NO GO without modifying the BB. Is that specific to the Alfine hub alignment?

    Thank you,

    1. Yes, the only hub that currently will align is the Rohloff. Sorry

  5. good evening!
    This is all great research and information. I’m very happy that I’ve stumbled upon it.
    As of March 2018, Gates now offers a CDX belt ring and cog which are Di2 specific. There is a particular offset which I believe may accommodate an Alfine 11 IGH with the BBs02. I have the cog and ring on order and should have them in hand by the end of the month. I’ll report back with findings!

    These certainly are interesting times!!

    1. This is great news Christopher. this kind of input is valuable to our community effort. Please let us know the results of your efforts so others can benefit.Doug

  6. Hey every one.
    I have a Cube Hyde race, any advice before buying the bafang motor?

  7. Hello,

    anybody tried the part ? They pretend you can use it to mount a bafang with gates belt drive.
    https://em3ev.com/shop/bbshd-chainring-adaptor/?currency=USD

  8. Thank you for the info. Check out this manual on gates’s site
    http://www.gatescarbondrive.com/~/media/files/gcd/gates-cd-ebike-compatibility.pdf?la=en

    1. Thank you James for helping to keep our community updated.

  9. I have a CoMotion Americano Rohloff/Gates belt drive. It has a Co-Motion eccentric mount w/Angular Contact Bearings Wheels Mfg BB-MTB-3 1.37” x 24T 68 mm wide.
    I measured the spacing from center of axle to outer housing of bracket, it’s about 30 mm. So would the motor housing clear the bottom bracket housing?
    With the current setup, once the belt is tightened to spec, the rear wheel drops out, so there is no further adjustment. The bottom bracket can be removed, put back in, and the belt tension is good. So I believe that if I have the clearance, this will work.

    Please advise.

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