Cool nice rides I'd like to throw together an ebike build too but pretty expensive to do it right or to buy outright. Was more of a challenge than i expected making a big pulley and motor mount and getting everything lined up and tensioned properly (mostly struggled with getting pulley and wheel 100% lined up and concentric probably would be good to have the pulley on a bearing on the shaft but just had mine zip tied to the wheel, I pretty much followed Tom Stanton's V1 of the ebike build hes done some upgrades since then too though)