Standing on pegs = lower centre of gravity?

[FJRider]

This is really interesting.
If the rider were absollutely rigid and at the same height as the seat, nothing would change.
(Consider a rigid 50 foot rider - the c of g of the bike plus rider would be high alright!)
In fact, the rider acts as both vertical & torsional decoupling (via his legs) for his own mass (which rides high).
Hence FOR A LIMITED FAST MOVEMENT in each of these axes the rider mass will be decoupled from the bike to some extent.
(by allowing the rider movement to be partly independant of the bike.)
The effect on the bike by allowing this limited movement must be to lower the apparent dynamic c of g of the bike.
I still think the main benefit is to reduce the dynamic loading on the bike suspension during the hump transition, and to increase rider comfort!
Never thought about this before!

When sitting on a bike ... your weight is supported by the motorcyce seat .... almost NO weight is supported by the footrests. When you stand ... ALL your weight is on the footrests. No weight is even taken by the bars. The force on the bars is a lever action of your whole body which makes bike control easier when you stand.

[Subike]

When sitting on a bike ... your weight is supported by the motorcyce seat .... almost NO weight is supported by the footrests. When you stand ... ALL your weight is on the footrests. No weight is even taken by the bars. The force on the bars is a lever action of your whole body which makes bike control easier when you stand.

I agree with you on some of your post F J, but not all of it.

If you have ever ridden a hard tail motorcycle, then understanding this is easier,

You can control the bike when standing on the pegs, by using your weight on the pegs only.

With no need for input from the handle bars other than to keep your balance.

But this also depends upon your level of skill.

[ducatilover]

The sole purpose of raising yourself like so is to use your legs as suspension, this gives the bikes chassis/susp less problems/effort as a human body going over a bump will naturally stiffen up, and being a stiff ninny on the bars is a horribly stupid idea. So, simply, it's so you don't interfere as much as you would with the bikes "natural" movements.

Or so I'm told, I ride a GN250/300/kaboom though

[sootie]

When sitting on a bike ... your weight is supported by the motorcyce seat .... almost NO weight is supported by the footrests. When you stand ... ALL your weight is on the footrests. No weight is even taken by the bars. The force on the bars is a lever action of your whole body which makes bike control easier when you stand.

Agree with that, and the easier to control bit actually, but the original post was about changes to the c of g.
I do raise my weight on humps, and definitely prefer to do so, but I think for my sort of riding, it is mainly protecting my bum & spine!

[neels]

Just think of the force vectors, and where they are acting;

The total mass of the rider acting at the point where they meet the seat,

or the mass of the rider divided roughly in half acting lower down on the pegs.

Do the maths, you'll see why it makes a difference.

[ducatilover]

Just think of the force vectors, and where they are acting;

The total mass of the rider acting at the point where they meet the seat,

or the mass of the rider divided roughly in half acting lower down on the pegs.

Do the maths, you'll see why it makes a difference.

Yes, until you hit a bump/pothole, then your COG is shifted else where.
It's not to lower the COG, it's to stop you being a numpty with the steering