Standing on the Pegs "Lowers Your Centre of Gravity"?
#31
08-31-2013, 02:39 PM
One side note that might emphasize my point...
What happens to that combined load when a rider unweights the pegs?
Both masses are still present, the combined center of mass is still nearly the same location, but the motorcycle chassis perceives there is less load and it will go over a bump or log easier. Again, the trials rider who can bounce around by unweighting and even clamping their feet against a bike pulling it upward due to application of the rider's mass upward, maybe backward or forward depending on if they're bouncing the rear or front tire or both.
In a moment in time the two as one still have the same center of mass by calculation, but the motorcycle chassis is perceiving something totally different in loading. The rider has radically altered the effects of gravity of the motorcycle chassis using a jumping action to unweight the bike while still on the bike! - his mass going up off of the chassis and with boots clamped against the frame, adding an upward force it in the process.
Same bike, same rider, same masses, same stationary center of mass by calculation, but hey, it's all about the dynamic nature of the rider, how they apply forces and how they can affect the motorcycle itself. It never is just "that simple" now, is it?
Tell that to James Davis!
What happens to that combined load when a rider unweights the pegs?
Both masses are still present, the combined center of mass is still nearly the same location, but the motorcycle chassis perceives there is less load and it will go over a bump or log easier. Again, the trials rider who can bounce around by unweighting and even clamping their feet against a bike pulling it upward due to application of the rider's mass upward, maybe backward or forward depending on if they're bouncing the rear or front tire or both.
In a moment in time the two as one still have the same center of mass by calculation, but the motorcycle chassis is perceiving something totally different in loading. The rider has radically altered the effects of gravity of the motorcycle chassis using a jumping action to unweight the bike while still on the bike! - his mass going up off of the chassis and with boots clamped against the frame, adding an upward force it in the process.
Same bike, same rider, same masses, same stationary center of mass by calculation, but hey, it's all about the dynamic nature of the rider, how they apply forces and how they can affect the motorcycle itself. It never is just "that simple" now, is it?
Tell that to James Davis!
But seriously, the only reason I posted Davis' description was that it was about as good as any of the better descriptions out there. When you search the issue of standing on the pegs of a motorcycle, you get an overwhelming response that it doesn't technically lower the COG...even though it's extremely beneficial in many motorcycle handling scenarios. We're all probably overthinking the issue here.
#32
08-31-2013, 03:31 PM
I'll tell you what happens when you unweight the pegs...you're going over the handlebars...LOL!
But seriously, the only reason I posted Davis' description was that it was about as good as any of the better descriptions out there. When you search the issue of standing on the pegs of a motorcycle, you get an overwhelming response that it doesn't technically lower the COG...even though it's extremely beneficial in many motorcycle handling scenarios. We're all probably overthinking the issue here.
But seriously, the only reason I posted Davis' description was that it was about as good as any of the better descriptions out there. When you search the issue of standing on the pegs of a motorcycle, you get an overwhelming response that it doesn't technically lower the COG...even though it's extremely beneficial in many motorcycle handling scenarios. We're all probably overthinking the issue here.
#33
08-31-2013, 05:23 PM
Join Date: Jan 2013
Location: Las Vegas, NV
Posts: 1,422
Let's look at it like this. If you had a klx250s, and you put a 4ft tall stool on the seat and sat on it while riding, would the total central mass of the object (person and bike) be higher or lower? Higher because of equilibrium. If this weren't true than weight wouldn't effect an objects center of mass. But it does (to a certain point depending on where and how it is connected to an object).
Another point. Have you ever seen the little toys you put on desks that have all the weight on the tip? So they seem to hover on one point? When you put weight on the rear end of the object the center of mass changes and it won't balance on it's tip. http://www.xump.com/Images/Products/...Eagle-500A.jpg
All this is relative of course, a klx weighs what, 290 wet? Average male about 200 lbs, that's a lot of weight to add. Doing the same to a 800lb cruiser has a much less of an effect.
Another point. Have you ever seen the little toys you put on desks that have all the weight on the tip? So they seem to hover on one point? When you put weight on the rear end of the object the center of mass changes and it won't balance on it's tip. http://www.xump.com/Images/Products/...Eagle-500A.jpg
All this is relative of course, a klx weighs what, 290 wet? Average male about 200 lbs, that's a lot of weight to add. Doing the same to a 800lb cruiser has a much less of an effect.
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