small wheels and "bump steer"
I think it's generally agreed that, for a properly designed bike, smaller wheels do not necessarily imply less comfort or poor handling. Unfortunately, it seems that it's often the case that smaller wheeled bikes aren't very carefully designed, often leading to poor handling and uncomfortable riding. However, what about the tendency for large bumps, potholes, etc to unexpectedly steer the bike. Does anyone think that this "bump steer" phenomenon is increased with smaller wheels?
I personally am a bit undecided. While, on the one hand, I feel that my 20" Downtube definitely experiences more bump steer than my 26" junker, on the other hand, I often get the impression that the 8" wheels of my Carryme stick to the ground, almost impervious to bumps, like suction cups. I suppose one way to rationalize my feelings is to attribute the sensitivity to bump steer of the Downtube to less stable geometry and consider smaller wheels as actually being superior in terms of bump steer due to the larger percentage of the wheel being in contact with the ground (so hitting a bump does not change the contact point much). On the other hand, perhaps I only perceive the Carryme as being more stable over bumps because I don't ride it as fast as the Downtube.
So I ask, what are the factors which affect handling over bumps? Does suspension make any difference (whether from a distinct suspension or simply pneumatic tire pressure) or does that only affect comfort? Would wider handlebars make a big difference? Could geometry considerations like trail really have an affect despite the fact that trail is relative to the contact patch (which is a moving target when bouncing over large bumps)? What about higher/lower center of mass? Although all ideas are welcome, has anyone actually studied this?
Last edited by makeinu; 02-28-08 at 12:04 PM.