MID drive and Gates Carbon Drive

Modified Ibera Mini Commuter rack and bag completed. Converted the rack from a seatpost mount to a stubby low and forward chain stay rack that sits almost in an extra large seat bag position:







The Gates Belt Drive is very enjoyable to ride. Quiet and smooth operation, and no maintenance. Can't wait to power it up once the battery I want gets restocked. Another belt drive on the road!

I just wanted to add some thoughts here on the mid-drive plus belt combo.

The Gates belt drive demands an absolutely straight driveline UNLESS you run the belt really tight. I'm running the BBS-HD on a Spot Acme with Alfine 11 and Gates belt drive. It's not been a good experience. I'm currently on my third belt as they have a tendency to break on you. The Alfine 11 is not holding up well at all and I've already replaced the internals once. Likely needs another set of internals.

I'm currently building a Rohloff to replace the Alfine 11 as they are supposedly a lot stronger and have a straight driveline with a BBS-HD. But, as you know that's not a cheap exercise... Likely close to $2k with a strong wheel build.

Net-net, I wouldn't run the BBS-HD on a belt or on an Alfine 11. The 8's are a lot stronger which might be a better bet with a chain. Otherwise, you're going to be custom machining a custom Gates sprocket to get the driveline straight. And the Alfine 11 can't take the power.

If I were to start all over again, I would buy a Riese & Muller bike like my wife did after seeing my struggles. I'll be in about the same money as selling my bike and buying a Riese & Muller with the Rohloff +BBS-HD and it still won't be as nice as hers.

I would like to suggest that the Gates belt-drive is a wonderful option for the BBS02, but it "might be" less than optimal for the BBSHD. I am sad that you did not find that info before your attempt at doing this...

If you are already building a Rohloff hub, congrats, but...for the gentle reader,I would suggest that..softening the throttle response can go a long way towards allowing the hubmotor to survive. ie, if you like popping wheelies, you should not use an IGH...

Just a suggestion...

I have to agree with the BBSHD and your incorrect beltline being the issue. A RM Rohloff Gates Carbon Drive ride is insanely expensive. It has less than half the power output of the BBSHD and a proper beltline to a Rohloff rear IGH.

1000 watts and almost 1-1/2 times that at peak power for the BBSHD will destroy "bicycle" parts. It's as simple as that.

I run a BBS02 Gates Carbon Drive to a Sturmey-Archer 3spd IGH and have no issues whatsoever for over 2,000 miles. I also run a BBS02 chain drive to a Sturmey-Archer 5spd that is approaching 1,000 miles of use fast.

I am considering building a Soma Juice 27.5+/29 BBS02 Gates Carbon Drive with Sturmey-Archer 5spd next (they make a 26T Gates cog for it). My initial thought is to face the drive side of the Juice 73mm BB down to 68mm (or as much as can be faced until the BBS02 hits the right chain stay) and combine a 42T Lekkie Bling Ring and a Gates Carbon Drive 50T front belt sprocket to get the line spot on. Still have to do the calculations, but I think it is doable.

Using a Sturmey-Archer 3spd cassette rear IGH like my Soma B-Side above is a no brainer getting the beltline spot on, because of all the adjustment on the rear cassette with single belt cog.

Even the BBS02 has way more power than all the premade mid-drive electric bikes. For my money, the BBS02 is the cream of the crop! I like having that 1000+ watt peak on throttle boost demand when needed and all the programmability too; plus the non proprietary battery options. You don't get any of that with a premade. At least not yet...

justinpirie said:

I just wanted to add some thoughts here on the mid-drive plus belt combo.

The Gates belt drive demands an absolutely straight driveline UNLESS you run the belt really tight. I'm running the BBS-HD on a Spot Acme with Alfine 11 and Gates belt drive. It's not been a good experience. I'm currently on my third belt as they have a tendency to break on you. The Alfine 11 is not holding up well at all and I've already replaced the internals once. Likely needs another set of internals.

I'm currently building a Rohloff to replace the Alfine 11 as they are supposedly a lot stronger and have a straight driveline with a BBS-HD. But, as you know that's not a cheap exercise... Likely close to $2k with a strong wheel build.

Net-net, I wouldn't run the BBS-HD on a belt or on an Alfine 11. The 8's are a lot stronger which might be a better bet with a chain. Otherwise, you're going to be custom machining a custom Gates sprocket to get the driveline straight. And the Alfine 11 can't take the power.

If I were to start all over again, I would buy a Riese & Muller bike like my wife did after seeing my struggles. I'll be in about the same money as selling my bike and buying a Riese & Muller with the Rohloff +BBS-HD and it still won't be as nice as hers.

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Please post up pictures of all your broken Gates Carbon Drive belts. I've never seen a broken one before. How ripped up is the center line groove from the improper belt line?

Sorry for some reason I wasn't getting replies to this thread. (Super annoying it doesn't do that by default) I didn't take any pictures of the broken belts. It would break on one edge between the teeth because it had jumped off and it was super tight.

After replacing the Alfine 11 with a Rohloff I had a couple of perfectly trouble-free years riding. The straight driveline and the strength of the Rohloff was awesome.

We have just moved out of SF to the East Bay so I'm selling the Spot and going to put that setup on a cargo bike, maybe a Bullitt? I replaced the Spot with a titanium Seven, with a Rohloff of course :lol: