Why guess? Measure it for yourself! Put one wheel on a scale, lift the other to the same height, get someone to balance the bike for you while you sit on it in a riding position. Measure the other wheel, then change bars/clip ons and repeat.
Man thats tempting. Unfortunately I switched to an upper triple from an S and I'd have to drill it which I'd rather not do. Might be worth it though...Why guess? Measure it for yourself! Put one wheel on a scale, lift the other to the same height, get someone to balance the bike for you while you sit on it in a riding position. Measure the other wheel, then change bars/clip ons and repeat.
This changes the rider's centre of gravity.Essentially all that has changed is that the rider is a little more leaned forward with the clip ons.
Motorcycle Dynamics by Vittore CossalterIf anyone has any good links for stuff to read on the subject that would be awesome.
The point made in the OP was that the center of gravity will not change because of the lean.This changes the rider's centre of gravity.
I think OP is saying that if mass behaves this way (acts through the point of contact) - then that hasn't changed because of the lean. Someone with better physics chops will have to chime in on this.I've read that when you stand up on a bike and put all your weight on the footpegs it actually lowers the center of gravity of the bike (despite the fact that the center of gravity of your body is higher when standing) because the place where your weight is actually resting is lower than when you're sitting.
nah - we are all theoretical physicists here.Why guess? Measure it for yourself! Put one wheel on a scale, lift the other to the same height, get someone to balance the bike for you while you sit on it in a riding position. Measure the other wheel, then change bars/clip ons and repeat.
Rider's COG moves with the rider. Lean back, lean forwards, lean sideways, shift back in the seat, shift forward in the seat, etc. Rider's COG is in a different position with each movement. Rider's COG would be in a different position in each image below (handlebars vs clip-ons vs aggressive clip-ons). Motorcycle COG stays the same. Combined COG moves with rider movement. With clip-ons, combined COG is further forward.The point made in the OP was that the center of gravity will not change because of the lean.
That is an excellent observation. There is more than 1 point of attachment. Maybe you should've taken those physics classes. You seem to be good at thisWhat I'm thinking at this point is that maybe with the more upright riding position you don't have to put as much pressure on the footpegs ... I never took that many physics classes.
I guess you're missing one fundamental point.But the OP is suggesting that the way physics works is that an attached mass acts through its point of attachment - and the overall COG of the bike will not change so long as the point of attachment of the mass (i.e. the rider's ass attached to the seat) does not change.
Yes - correct. I was missing that entirely. I realized that when @BlurpleGatorade mentioned the footpegs.The rider is attached to the bike in 3 different points: footpegs, seat and handlebar.
From a static perspective, if you're sitting on a bike that is not moving (no horizontal forces). Let's assume it's on stands. As Skywalker pointed out, your feet are resting on the pegs, your butt is on the seat, and your hands on the handlebars. This is to counteract the downward force of gravity which is applied at your COG. The point where the COG acts is the sum of all gravitational forces acting on the rider's body - it's a simplification so we don't have to consider all the individual elements. It moves with you.Thanks for the replies everyone! Love those pics Bastak and thanks for the explanation. I'm curious as to what specifically causes the change in combined COG. Obviously in the pictures above the riders COG would be different for each picture but their points of contact are the same. What I'm thinking at this point is that maybe with the more upright riding position you don't have to put as much pressure on the footpegs to keep your torso from falling forward, so when you lean forward farther and have to keep a higher pressure on the footpegs it moves your weight forward. I never took that many physics classes though so I might have a fundamental misunderstanding. Let me know what y'all think.
(also I definitely need to get a copy of motorcycle dynamics, its on my list as soon as I finish my second read of Twist of the Wrist 2)
Yep and its the same principle with regard to forward/aft weight transfer when changing to clip ons from a handle bar set up. There - question answered!@BlurpleGatorade here's the best image I could find online showing rider COG (right), motorcycle COG (left) and combined COG (middle). All else being equal, if the rider hangs off more, the rider COG moves more to the right, motorcycle COG stays where it is and combined COG moves to the right as well (to a lesser degree than rider COG).