Longer swingarms
Sat, 03/07/2010 - 14:33
I was wondering if you could explain to me why a longer swingarm contributes to a better ride? I'm not talking about stretched arms for looks/drag racing, but say when a manufacturer goes to a stacked transmission and keeps a similar wheelbase as the old model but uses an elongated swingarm.
Wed, 07/07/2010 - 06:32
#2
Re: Longer swingarms
DJ.. I'll assume that your question is in part stimulated by the Sprint ST chassis getting a longer swingarm in its transformation into the GT model. In that case everything forward of the swingarm pivot is identical so in effect the rear wheel is extended backwards. This results in the centre of gravity being shifted forward and its height as a proportion of the wheelbase reduced. These C of G changes would reduce the bikes pitch moment (brake dive, rear squat under power & pushing wide driving out of corners). The standard "cure" for excessive chassis pitch is increasing low speed compression damping, which has a negative effect on ride quality. So all things being equal extending the wheelbase on a bike should enable a better ride if the factory finds it can control pitch with less compression damping.
BTW the BMW F800R has 1520mm wheelbase close to the Sprint GT with the F800S having a 1466mm wheelbase... weird huh?
Wed, 07/07/2010 - 07:20
#3
Re: Longer swingarms
Actually I was thinking more along the lines of this:
http://www.ashonbikes.com/content/suzuki-gsx-r1000-technical
I'm no expert on 'owt, but, a longer swinger lets the relatively short shock travel work more efficiently. Cos of leverage and the weather and weak attitudes. Lessens chain "wind up" too.
I know peeps what can help you, but only with crayons in the morning.
Seriously though better calculated shock travel rates/springs, and shocks that cost more than e20 as stock, not joking here, work in manuf. eng. and have costed this stuff over the years...To make almost anything these days costs very little.