making up cassette

[bernieo]

i put together a ebike from bafang BBSHD kit . I had to remove 3 sprockets from cassette to get chainline right . after nearly 2k miles , i need to replace sprockets ,due to being worn.
my trouble is i can not find any shimano cassettes that will split or separate .
sunrace used to do 7 speed that came apart , no longer .
Does anybody know of supplier that sells separate sprockets or cassettes that can be disassembled . i need 12 16 21 28 teeth sprockets
i have been looking everywhere on the net.
thanks.

 

[Stefan Mikes]

What is the number of speeds (gears) in your cassette?

 

[PedalUma]

i put together a ebike from bafang BBSHD kit . I had to remove 3 sprockets from cassette to get chainline right . after nearly 2k miles , i need to replace sprockets ,due to being worn.
my trouble is i can not find any shimano cassettes that will split or separate .
sunrace used to do 7 speed that came apart , no longer .
Does anybody know of supplier that sells separate sprockets or cassettes that can be disassembled . i need 12 16 21 28 teeth sprockets
i have been looking everywhere on the net.
thanks.

For clarity do you require an inner side screw on freewheel cluster of gears, or a freehub cassette of gears with an external lock-ring? If this sound like gibberish, as it will to many, than simply look up these terms.

 

[bernieo]

bike originally had 7 speed rear cassette .
its the freehub cassette with the locking ring . i learnt the hard way ,by ordering wrong type .still gathering dust in garage . :-(
I'm surprised none of the sprocket makers are not doing custom cassettes ,built to order (except very high end).
their must be lots of bafang BBSHD owners having same problem .(chain line is a problem on that model)

 

[Stefan Mikes]

bike originally had 7 speed rear cassette .

Small Shimano cassettes are not serviceable because of their low price. You replace the whole cassette.

10, 11 and 12 speed ones are serviceable except for the top high end ones (which are milled from a single block of metal).

Besides, the cassette model number is usually printed on the back side of the largest sprocket.

 

[Chargeride]

The issue with a freehub is also if you space out, you end up with a high torque low gear sprocket that is sitting on the splines with a tiny contact area.
The larger ones are usually bolted to a spreader.
I took apart a huge dinner plate cassette I got 2nd hand off a friend, I used the spreaders as a spacer, bit of a botch, but it works.

 

[bernieo]

seem to be getting no joy yet. I'm considering buying another full mtb and transplanting the bafang mid drive unit and battery .
has anybody any prior knowledge of a stock pedal mtb that will accommodate a bbshd motor and use full existing rear cassette.
ie does not have problem with chainline . its worth a try ?

 

[Stefan Mikes]

Or, buy yourself a production e-bike?

 

[bernieo]

valid point ,but paid best part of £800 for bafang kit ,I'm happy with it .on the flat get over 100miles on 1 charge
production ones are 16mph limited, no throttle , and 250watt max (officially in uk)
ive emailed Bafang ,to see what they can come up with, not yet got reply
thanks

 

[PCeBiker]

What about buying a used ebike that has been "bricked" by a proprietary company that went belly up, and install your kit on it?

E-bikes are being thrown in the garbage because proprietary parts aren't available.

 

[m@Robertson]

Re-ordering the cassette cogs is a common hack in the DIY community, but its an extreme solution (as in a hack; kludge; bodge etc.). I've never needed to do it after many years of building with BBSHDs on a wide variety of bike types. You can typically solve alignment problems by making a change to the front chainring. Either you change to a different chainring that has different offset, or you move to a different size that lets you use different gears, so you solve your alignment issue since you are now on different cogs.

Monolithic cassettes (i.e. pinned together) are a big benefit as they distribute the force of the mid drive across the entire cassette body, which keeps the cog from chewing into the cassette. A pinned-together cassette used to be only found on the cheapest of the cheap bikes in, say, 2015. Flash forward to 2025 and you find them available in much higher quality products, coupled to steel cogs... another thing that used to be associated with cheap parts. Look at Shimano's Linkglide system... Pinned together, steel cogs 300% claimed reliability increase (which appears to be real) and the damn things are $120 a pop.

How To Build a Mid Drive Ebike That Doesn’t Break

Mid drives up the ante on the required competence of the builder. Read this so your bike lasts without things breaking or wearing out early.

talesontwowheels.com

ALSO: If you are trying to find 7-speed cassette parts, you may as well stop looking. Thats ancient tech. Not surprised at all you can't find anything. I would change the drivetrain to something with more speeds and thus more parts available. See the above article. A 30a BBSHD running on a 52v battery can run just fine on an 11-speed system. There is no need to reduce your gear count for reliability, as you'll hear is necessary or beneficial by less experienced builders. Also, a 7s cassette is old stuff so your cassette body underneath and your frame spacing needs to be taken into account. Check out the 8s and 9s drivetrains in the article link.

 

[Stefan Mikes]

bafang kit ,I'm happy with it .on the flat get over 100miles on 1 charge

What is the battery capacity (Wh, or V * Ah)?

 

[Mike_V]

i put together a ebike from bafang BBSHD kit . I had to remove 3 sprockets from cassette to get chainline right . after nearly 2k miles , i need to replace sprockets ,due to being worn.
my trouble is i can not find any shimano cassettes that will split or separate .
sunrace used to do 7 speed that came apart , no longer .
Does anybody know of supplier that sells separate sprockets or cassettes that can be disassembled . i need 12 16 21 28 teeth sprockets
i have been looking everywhere on the net.
thanks.

Hi Bern,
You're on the right track keep at it. } >NO whole new bike ? < {
Most cassettes may be disassembled and then you can re-stack as required to optimize the mid drive chain line on your bike and BBSHD and performance over the chosen terrain. Buy used cassettes - I seek out the older ones because thick steel and of the metal spacers instead of plastic. For shimano you have to match the lock ring to the last sprocket or two depending on the design. I prefer Sunrace. Grind off with dremel or filing the locking pin on the back of the cassette for some - two pins of three are usually for positioning. Some good old ones have retaining screws. Sprockets that are damaged can be seen and left unused from your collection of used cassettes. No need to replace the retaining pins, because the sprockets are held in place by the features of the free hub and it's lock ring.
M.V.

 

[Mike_V]

"their must be lots of bafang BBSHD owners having same problem .(chain line is a problem on that model)"
Yup
References for modification and custom eBike builds are in this forum found upon searching.

Home - Electricbike.com Ebike Forum

The Ebike Revolution starts here. Everything you wanted to know about high power and affordable ebikes.

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This old cassette design with three long attachment bolts, metal spacers and low wear plated steel sprockets was a pleasure to disassemble: