SteppnRzr wrote: ........ Not being a smartass, but why do you say rigid frames are stupid?
In addition to lack of comfort bikes with hardtail frames handle very poorly compared to bikes with rear suspension systems. Consider the following:
Bike A has rear shocks (or a single shock). Good shocks help keep the tire in contact with the road. Bike A rides over a speed bump. As the rear tire/wheel lifts over the bump the axle is pushed upwards; this compresses the shock absorbers. The rear of the bike is lifted, but not the full height of the speed bump. The distance it is lifted is approximately the height of the speed bump minus the amount the shocks were compressed. The mass of the rear of the bike moving upwards and the velocity of that movement will tend to lighten the rear at that moment, and if the bump is tall enough or the bike’s speed great enough the rear of the bike may become airborne. This lightening is proportional to the mass and upward velocity of the bike. This movement and associated lightening (and resulting vertical momentum) of the rear is reduced on a bike with shocks because some of the energy is absorbed in compressing the shocks. Less vertical momentum is good. As the rear lightens, the compressed shocks rebound (lengthen) to help push the rear axle down to maintain contact between the tire and pavement. As the rear returns to its normal weight the shocks compress to their normal length softening the movement. With proper shocks there should be no bouncing after passing the speed bump.
Bike B has a rigid rear frame. Hardtail frames do nothing whatsoever to keep the tire in contact with the road. Bike B rides over the same speed bump at the same speed. As the rear tire/wheel lifts over the bump the axle is pushed upwards. Because of the rigid frame the rear of the bike is lifted the full height of the speed bump. With no shock absorbers all the energy is transferred from the axle to the frame of the bike, and since there are no shock absorbers the velocity of the upward movement and resulting vertical momentum is greater than that of Bike A. More vertical momentum is bad. The mass of the rear of the bike moving upwards and the velocity of that movement will tend to lighten the rear at that moment, and if the bump is tall enough or the bike’s speed great enough the rear of the bike may become airborne. Again, this lightening is proportional to the mass and upward velocity of the bike, so because the upward velocity of Bike B is greater than that of Bike A the lightening and potential loss of contact with the pavement is also greater than that of Bike A. As the rear returns to its normal weight and drops back down, with no shocks, the rear of the bike makes a harder landing and may even bounce up again.
Now consider that both bikes may be going at speed through a turn when they hit a bump or pothole. The rider on Bike A may come through it fine while the rider on Bike B must change his shorts and repaint his bike.
In other words, hardtail bikes handle like crap; that's why really good handling bikes and bikes that race on anything other than a straight track have big investments in very high quality shocks. Ed
