Tires might be the one bike item typically destined for the landfill.
They are likely toxic, and should not be reused. (maybe repaired, maybe light re use). Schools, for instance, are rethinking the mulching of tires for playground fall areas.
Let's rethink bike tires!
from a 2016 article:
"First off, Continental Tires reports they’ve managed to construct and have successfully tested the first-ever set of tires in which the tread is made from 100 percent dandelion natural rubber used as a polymer. That’s right – dandelions – the scourge of a million lawns.
The official name for the substance is Taraxagum, and it was developed in conjunction with the The Fraunhofer Institute for Molecular Biology and Applied Ecology, Julius Kuehn-Institute, and EKUSA, Continental says it could put dandelion-based tires into production within the next five to 10 years."
from: https://www.forbes.com/sites/jimgorzelany/2016/06/03/tires-made-from-weeds-a...
Grips can be cork, housing can be metal, seats leather, and all sorts of other non/less toxic materials.
Heck, we have a dream to 'grow our own bicycles' here on our free cycles property, fitting with a theme of permaculture.
Bob Giordano, director, free cycles missoula missoula institute for sustainable transportation http://www.freecycles.org/