When I was a kid I used to ride BMX bikes and race then like crazy, In fact I wish I had stayed with it and made the transition to motocross earlier in life. In any Case, BMX bikes were always looking for a way to get lighter and still have parts that were strong enough to handle the business of riding.
I often wonder why Motocross bikes have never made the transition to any other type wheels besides spoked aluminum type rims. On BMX bikes I remember using a rim called “Z” Rims, I’m pretty sure they where made out of graphite, so they had a little flex to them but they were very strong and light, and so many people riding back then made the switch to these type of rims. They also used Skyway Rims called “Tuff 2’S ” Which were graphite also and look like the rims on this Yamaha. We also used Sealed bearing hubs called Bullseye Hubs (Back in the day those were the best) and when you would flip your bike upside down and roll the wheel, the hubs were so well designed that the wheel would continue spinning until you stopped them.
Just a thought! I’ve included some pics for the fun of it, but I really wonder sometimes if these rims could work on a motorcycle in todays climate as Supercross riders. They certainly could help with weight.