OK... I'm sure this has been hacked around here quite a bit already, but I'm new here. Let me start with what I know: In automobile suspension design, you attempt to limit the "unsprung" weight because it's uncontrollable. The sprung weight you can control and tune.
But, I'm having trouble applying this concept to biking. It seems to me like the entire bike/rider on a road bike is unsprung. Therefore, it does not matter if the weight is on the rider or the bike. Therefore, with the exception of those of use in perfect condition (me, of course) you are just as wise to cut your own weight by a pound as you are to spend $500+ cutting the bike's weight by the same amount. Of course, the rider is movable, so in a sense it's "sprung" weight".
But, practical experience seems to challenge this. I know that getting on a light bike makes me go much faster... and if doesn't seem to be the 5 lbs difference... or is it ? Is it just an illusion ? If I hung a 5lb weight on me and then got on a light bike would I feel the same as the heavy bike (mechanical smoothness of the more expensive bike aside) ?
Heavy rider, light bike is more comfortable than light rider, heavy bike. The rider can be considered as "suspended" because the tendons in his/her legs are highly efficient shock absorbers. If he/she gets out of the saddle, that is. If the rider sits like a sack of potatoes, there's no advantage.
Heavy rider, light bike is more comfortable than light rider, heavy bike. The rider can be considered as "suspended" because the tendons in his/her legs are highly efficient shock absorbers. If he/she gets out of the saddle, that is. If the rider sits like a sack of potatoes, there's no advantage.
Which is why nobody rides like that over spots so rough the quality of the suspension becomes the key factor in control.
I'd like also to point out that the human frame is a far more active and intelligent suspension than anything ever installed on a mechanical vehicle, so the question of sprung and unsprung changes significantly.
