Is it possible to put a tire designed to fit a 3.5 " rim onto a 3" rim and if so how would it respond. Thanks for the help
Yes you can put a tyre designed for a 3.5" rim onto a 3"rim safely.
Bad news - it will tend to make the diameter a bit bigger because it is squeezing the 3.5" width into only 3".
(I think that is right anyway. It will distort the shape of the tyre slightly. When fat tyres first became a fashion statement people would claim they couldn't tell any difference if they squeezed a fat tyre onto a far too small rim. We just laughed and could tell by the wear pattern on the tyre that they never leaned around corners!)
ya thanks for the reply, I have found a couple of hopeful options one by IRC and one by Dunlop 130/70 and 130/80.