Looking for connections to Downhiller’s

I’m wanting used downhill bike tubes, specifically 26×2.5×2.7, they’re wider and thicker than normal, I want to reuse them, any ideas? 
Also if you use downhill tubes and have any ideas about what incentives would encourage you to donate them to be reused.
I’m investigating setting up a ‘cycle trust’ to help aspiring cyclist’s get to  races. Would this be useful in getting to downhill events?
If you’re a downhiller, what do you do with your used tubes? I understand many use them to hang bikes, protect bits of the frame by wrapping, keeping bikes secure on car racks. Great there is so much reuse already happening.