Re: front tires and their effects on wobbling at "high" speeds
i don't believe in balancing bicycle tires either, but i've argued that on too many other threads to re-type it here.
most of the causes have been posted already, but another thing that causes a sketchy bike is handlebar position, or more importantly, hand position.
if your hands are forward or inline with the front axle it can make a bike difficult to ride. it completely upsets the geometry of the bike. that's why apehangers are outlawed or regulated on motorcycles (in most cities.)
it's also why the "poorman's boardtracker" with upside down handlebars is so uncomfortable to ride.
a few other things i forgot:
innertubes can create a lump in a tire, making them uneven. a lot of tires these days are bigger, like 2.3's, and a 2.125 tube can't fill the space. i know this from personal experience. usually the area around the valve stem, where the rubber's thicker, can't pump up to fill the tire.
and some tires just suck. i've got a set of Duro whitewalls that are totally out of round. the whitewall's are uneven, too, and it makes me dizzy watching them spin around all crooked.
Last edited by bairdco; 10-08-2010 at 12:32 PM.