These are going on the 5055 dickyho motors (all black no sensor)
Also looking for 290mm belts. Found some on amazon (don’t know where else to look) but they’ll ship in about a month and I need something quicker.
I’m not sure if 15mm will fit for me, but I know 13mm will. So if you have 13mm i’d rather go for that.
thank
bumping this
found pulleys but no belts yet
Wow, this is actually a really hard size to find.
Not harder than 5M-255-11 for my exway 
That was way easier LoL
https://www.vbeltguys.com/collections/timing-belts-1/products/255-5m-11-synchronous-timing-belt
that’s before i discover vbelt, or even taobao sells these things
if u can make 280mm work i got a 4 pack for cheap 
I was skeptical but this worked, and I got the belts in fine.
For documentation sake for anyone else looking for belts, +1 for v-belt guys. lots of options