I’m a 7th grader, and am doing a unicycle related science fair project. I had someone coast 5 meters, with different tire inflations, and I timed him. As I expected he went slower with the way under inflated tire, but I need some research about tire inflation, and its affect on speed, but when I google search it, it dosnt come up with anything helpful. Could someone point me to a good website. 
You pretty much said it yourself. More air -> harder tire -> less rubber on ground -> less friction -> more speed.The pattern of the tire affects too. I’ve seen a finnish site that had info about inflation and how much effect different tubes have on friction. The mass of the tire also affects. If you have a heavier tire it rolls a bit farther (and if you compare to a lighter tire at the same spot, faster).
The only problem I see with timing somone coasting is that thier speed starting might be slightly different every time which would change your results and not give you the results you want.
Re: science fair
On Mon, 5 Jan 2004 17:15:39 -0600, Rob-the-unrepentant
<Rob-the-unrepentant@NoEmail.Message.Poster.at.Unicyclist.com> wrote:
>I had someone coast 5 meters, with different tire inflations, and I
>timed him.
I suppose that was done on a bike, not a unicycle?
>I need some research about tire inflation, and its affect on
>speed
Schwalbe has (or had) a graph of rolling resistance version tyre
pressure on their website. I forgot the url. If you Google for a few
of those terms combined, you may find it and other helpful sites.
Klaas Bil - Newsgroup Addict
You have to keep in mind that those of us who post on RSU are not normal. - John Childs
Go to google, and enter:
“rolling resistance” “tire pressure” research
You will find a variety of articles.
Good luck,
David Maxfield
Mitchell, SD