DC motor mounting terminology


Not technically a vehicle but it is a 24v DC motor (I believe these are used in scooters) so I thought you’d be the crowd to help me.

I have this motor MY9764 450W 24V DC Motor

I want to mount a pulley do it to drive a wheel. Thing is I cannot figure out the search term to find the part I need. It’s got a DD flat shaft with female tread (I don’t know if that’s right but it turns up the search results that look closest to what I want.)

I have tried looking for various saw and grinder pressure plates but none match the dimensions of the shaft. I assumed that I wanted a flange but I cannot find a flange that matches the dimensions either.

Can someone point me in the direction of the correct mounting hardware?

I have searched exhaustively but I feel like my limited understanding of the terminology is making my searches ineffective.


If I understand you are looking for some type of pulley/sprocket that is compatible with a 14mm dia D motor shaft? Of course, the type of drive system you want [chain, belt, etc] matters as to what exactly to search for?.

Did you notice that the motor manufacturer also offers motor and wheel sprockets?
Example: 11t Pitch Motor Sprocket for a MY1016
Strangely I could not find the size of the bore on any of their sprockets?
I would email them and ask them for help in finding a compatible motor and wheel sprocket et.

Other places I get mech parts from:

MCMasterCarr: McMaster-Carr

I searched across google, amazon and ebay for
“14mm bore pulley”
“14mm bore sprocket”
“14mm bore scooter sprocket”
“14 mm bore drive pinion sprocket”

Also include the motor model [MY9764] with combinations of the above

on amazon:

** on ebay**

I stumbled across a common motor type MY1020 perhaps it is easier to get drive parts for this motor.



One thing to be aware of is that mounting a pulley against the fan can block cooling air flow if it’s too big. I think that the sprockets that @donkjr found are more what they have in mind. I’ve seen DD sprockets and I think timing pulleys before, but as far as my recollection goes they have only been plastic.

As long as it’s small enough, any 14mm pulley will work if you can drill holes for set screws (grub screws) in it, or if it comes with the holes already there. With the DD shaft you want opposing set screws.

Note that for a pulley with a keyway, you could cut key stock to fit the keyway down to the face of the D cut on one side, but I’d expect that to have play and for that play to wear the shaft face, so it wouldn’t be my first choice.


Thanks for your reply!
The diagram does make it look like it’s a 14mm shaft but that is the distance between the flats. The shaft is 17mm diameter on the round sides. Closest sprocket or pulley I ever seem to find is 17mm diameter on the round side and 12mm on the flat side.

I took your advice to email them and they said they didn’t have any leads and my best bet was to get a local engineer to make something suitable.

Thanks for your help,

Thanks, unfortunately the diagram isn’t super clear and the shaft is actually 17mm diameter and 14mm from flat to flat. I can’t find any pulleys or sprockets that fit those dimensions and the motor supplier suggested getting an engineer to make one would be easiest.

That’s a good point about airflow. I think using set screws could work and I have found sprockets with a 17mm bore and set screws at a right angle to each other but so far no opposing set screws. I may just drill and tap the second screw in the location I want.

thanks for your help,

Drilling and tapping a new hole is reasonable and shouldn’t be too hard.

Have you drilled into a convex surface before? Do you have experience tapping? If you already know how, that’s great, but if you haven’t done either or both of those before, happy to share tips to help you succeed! :relaxed: