All tires are round, and all tires are flat
Gnarly 928 said:
I think Chris (BeeCharmer) may have hit on the 'ride quality' cause/feeling that many speak of when touting Tubulars. The shape of the tubular tire causes it to take corners a bit more "smoothly". I know on my sport motorcycles, tire cross section shape has a very big influence on how the bike "feels" as it corners. If you look closely at your bike tires, you can see that different types are shaped differently. As the wheels go from vertical to heeled-over on an almost round cross sectioned tubular, the 'contact patch' (where the rubber meets the road) "moves" predictably (in relation to geometry of the frame). With most clinchers, you will see the cross section shape is not really totally round, so as you tip the wheel and tire into a corner, the contact patch 'moves' (in relation to the geometry of the frame) in a 'non-linear' fashion, causing a subtile (usually un-noticable, by the average rider) change in the cornering forces. "Non-linear" I guess you could say, as the tire rolls over and up off it's center section, the contact patch "moves" .
What a bunch of hooey. In a very real since
all tires are round, and in another, equally real sense,
all tires are flat. In this regard, there is no difference between tubulars and clinchers.
The casing of all bicycle tires - both tubulars an clinchers - are bias ply. Unlike automobile and some motorcycle tires, there is no circumferential belting to constrict the profile of the tire. Because of the bias ply construction, and that the casings are thin and flexible and under a very high pneumatic pressure, all inflated bicycle tire casings are round.
What may give a tire an appearance of an oblong shape is due to varying thickness of the tread. If a tire has a tread that is very thick in the center, the tire may seem to "bulge" outward in the center. But although this bulge is real, it is not a factor of whether it is tubular or clincher - a clincher with a thin tread will be round, and a tubular with a thick tread will be oblong. But in either case, the casing under the tread is round. Because a bicycle tire is so narrow, it only takes a small difference in tread thickness to give this "oblong" appearance.
By the same token, all tires are also flat - in the ground contact patch. Because the casing is so flexible and the tread so thin, bicycle tires flex easily in the ground contact point, and contacts the ground in a flat patch. Because the tread is so flexible, and the pressure so great, small variations in tread thickeness are insignificant.
Gnarly 928 said:
Kinda difficult to describe this phenominum and it IS very subtile. Most riders would never be able to tell the difference just by feel. If you normally ride clinchers, you simply get used to how they corner, or never even notice the very very slight "tip-in" or "turn-in" inconsistency in your "line".
Yes, the differences are very subtle. Why, only those with senses fine enough to see the Emperor's New Clothes or feel the pea under the stack of matresses can detect the subtle improvement in handling. Apparantly Miles Rockwell (for MTB downhill World Champion) is not one of those sensitive enough, since he won the
Red Bull Road Rage (a downhill road race with plenty of technical cornering) on clincher tires.
So, if tubular tires handle so much better, do you use tubulars or clinchers on your motorcycle?