Replacing Cyclone 3000W reducer and reinforcing supports


10 µW
Mar 11, 2018
Hello everyone.

Fed up with the Cyclone 3000W motor mount bending, I'm making a new mount that I hope will fix all the problems. For this I am using parts that can be easily obtained. Since the motor without a reducer has almost the same width as my bottom bracket shell, 68mm, I have removed the planetary reducer and made a reduction with an auxiliary axle. This first reduction is for a 20mm wide HTD5M timing belt. 16T motor pulley and 80T auxiliary shaft pulley. This gives a reduction of 1:5.

With two aluminum plates I have fitted everything. The axle support is made with a Zitto BB386 bottom bracket adapter whose internal diameter is 24mm. I had a hard time finding something to use as an auxiliary axle, but in the end I found a carbon tube manufacturer on Ali and thought maybe I could make a carbon fiber axle by joining several tubes together. I bought for €31 four 500mm long tubes with diameters (external/internal) 24/22, 22/20, 20/18, 18/16 so if I fit them one inside the other I would have a 24/24 carbon tube. 16mm (8mm wall which I think is enough to withstand the twisting). With the 500mm length you could easily make 3 axles which would be equivalent to €10 per axle. It seems cheap to me, it has a very acceptable aesthetic and is also light and resistant (we'll see how it holds up). The HTD5M 80T aluminum pulley was solid, so I had to mill it with my old CNC3040 to lighten it and make a bracket for the freewheel. I also bought an adapter for the freewheel with an internal diameter of 24mm. On the other side of the auxiliary axle I have put a 19-tooth sprocket for a 428 chain and on the bottom bracket of the ebike, taking advantage of the Cyclone system I will put a 428 chainring (I don't remember the number of teeth) generating another reduction.

Additionally, I “machined” (if you can call it machining with a CNC3040) a tensioner for the timing belt.

What is the best way to glue carbon tubes? I thought about doing it with epoxy, but they fit with a lot of pressure and I think that inserting one tube into another will drag the epoxy.

Do you think it is feasible to fix the freewheel adapter using a through screw? Or maybe two screws? I have seen that in the manufacture of high performance drive axles they simply glue the steel cardan to the carbon fiber tube, but I can't do that because it would prevent me from removing the axle.

Thank you all.


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I finally bought a Z11 24-34 axle-pulley binding that fits the 24mm carbon fiber axle and the generic 34.5mm freewheel. Price on Ali €13. I think it is well built for the price. It is heavy, 345g. According to specifications, it supports a torque of 253Nm. I couldn't find anything lighter with those diameters.
I glued the carbon tubes with epoxy and the total weight of the tubes is 54g. Light and I think resistant to torque.
The total weight of the set is 1377g.
I still have to fix the 420 19T sprocket to the axle. I'll probably glue it on and if it slides I'll put in a couple of through screws.


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