Why not odd mm belts?

As someone who’s only recently broken his first belt after more than 2 years with the same 9mm belt, I went on eBay to find an identical 280mm HTD5 x 9mm belt and found an interesting option in front of me… 10mm belts. Knowing that my 12T pulley on the motor side had some play, I decided to give it a go. Well, my 5 belts arrived today and they seem to be working great, on the same pulleys that I was using for 9mm. It just made me wonder, whoever decided that 9/12/15mm were the best options? Why those odd measurements? My brother’s board has 12mm belts and I have friends who are running 9mm and 11mm so we tested all of them, and for each 1mm added there was a small but noticeable difference in feel between each ride (the thicker, the better!).

Anyways I’m happy with what I purchased, and from what I can tell there’s no harm in doing the same thing that I have, as long as your pulleys are long enough to take the belt. Any thoughts?

That’s what I say!

And for electric skateboards as well. More torque transfer with increased belt coverage.


Nice :slight_smile:

6mm, 9mm and 15mm are standard mass produced width. 12mm and any others needs to be cut by the seller to the correct width. :slight_smile: Source


just my assumption, I think people tried to make it somewhat competible with imperial system 1/3 is about 9mm 1/2 is 12mm 5/8 is 15mm.


I couldn’t find 12mm for my size so I ran two 6mm belts side by side and it seemed to work fine. Just an idea.

I think you are dead on. they are in fact imperial measurements just sold in mm for everyone else.

1 Like