Q.Hi There, A question triggered off the Natural Latex Bedding entry. For the treehugger-inclined, what are our bicycle tire options? In other words, which tires are better in terms of sustainable materials (including natural rubber or synthetics derived from renewable source material), production methods and reuse? When the fossil fuels run out, I want to make sure something still exists for my bike(s).
It's a darn good question, Andrew. And while we were pretty sure of the answer, thought it best to check with the 'oracle'. So we wandered over to Sheldon Brown's encyclopedic bicycle website
. (Don't go there without taking a packed lunch and thermos - you could be gone for a long time. You have been warned.) And he confirmed our suspicions. "All modern tires and most inner tubes use [synthetic] butyl rubber." Butyl being a petroleum derivative, isobutylene combined with isoprene. Carbon is added to the mix for durability, which is what gives industrial rubbers their black colour. Note that natural latex is a tan brown colour, as seen in the above mentioned bedding post.
Sheldon goes on to say "Some riders prefer latex inner tubes, because they can be a bit lighter than butyl ones. Some riders believe that latex tubes have less rolling resistance than butyl." But follows this up with the comment that latex is more porous than the synthetics, so needs to be pumped up more often. This is reinforced by the team over at Bike Pro, who reckon that butyl rubber "retains air 10 times longer than natural rubber, which is why some makers of latex tubes line the inside of the tube with butyl rubber."
The German company Schwalbe, (who do offer tyres with some natural rubber content) remark that they've stopped making latex inner tubes, due to their sensitivity to oil, light and heat. They seem to have done this reluctantly, because they give the latex tubes high marks for puncture resistance, as well as the already observed improved rolling ability.
So, Andrew, it seems that it will be possible to make natural latex rubber bike tubes and tyres again, after Peak Oil kicks in, but you'll need to have your bicycle pump forever primed.