Piggyback question of sorts: how do you know what size tires your bike can take? I saw a chart once but I am not sure if it is still up to date. I have 2 bikes (one hybrid, one cruiser), both 700x35 and I'd like to go thinner. I know both could do 32 but how would I know if 28 was too small? Is rider weight an issue when determining tire size?