Where can you find real life bike data ?

[C21]

Might be some guidance, its for the road bike version but i guess they would be similar mass distribution

I doubt 

[h106frp]

For $185,000 you would hope it had some resemblance.   

[Yohji]

Noticed on the CBR250R it is very high   

its tuning to banking speed and balance, and some moment

BTW,

chassis
{
   Mass = 47
   Inertia = 5, 3.4, 2.5

and

steer
{
   Mass = 8
   InertiaBox = 0.4, 0.8, 0.2

I'm still not understand "Inertia" and "inertiaBox" parameta well,,,, anyone can explain it? 

[h106frp]

Noticed on the CBR250R it is very high   

its tuning to banking speed and balance, and some moment

BTW,

chassis
{
   Mass = 47
   Inertia = 5, 3.4, 2.5

and

steer
{
   Mass = 8
   InertiaBox = 0.4, 0.8, 0.2

I'm still not understand "Inertia" and "inertiaBox" parameta well,,,, anyone can explain it? 

Hello Yohji,

Not a comment on your bike - it seems to handle quite nicely, just an observation r.e. 'real life values' vs 'GPB physics optomised (trial end error method)'.

As i understand it so far, the bikeED 'chassis center of mass' should be for the chassis component only so you might expect it to be quite low and somewhere around the crank/gearbox, the total bike center is then dynamically calculated in game from sum of the various components.

I am also looking for an explanation of 'inertia box' it seem to be some sort of matrix of ratios

[HornetMaX]

I'm still not understand "Inertia" and "inertiaBox" parameta well,,,, anyone can explain it? 

Inertia is ... weel, the inertia. What you don't understand ?

InertiaBox to me is just the inertia of the steering, don't know why it's called InertiaBox instead of simply inertia.

[h106frp]

For the chassis we have values, Inertia = 5, 3.4, 2.5, OK

for steering we seem to have ratios of 0 to 1,  InertiaBox = 0.4, 0.8, 0.2

If you reduce the second value (say 0.2) you will observe the top yoke physically moving in the longitudinal axis, A value of 1 fixes the yoke in this axis - they seem more like 'rigidity' values than calculated values for inertia. So i guess it has been scaled from 0=no restraint to 1=totally restrained for each axis.

Just guessing from observation

[HornetMaX]

For the chassis we have values, Inertia = 5, 3.4, 2.5, OK

for steering we seem to have ratios of 0 to 1,  InertiaBox = 0.4, 0.8, 0.2

If you reduce the second value (say 0.2) you will observe the top yoke physically moving in the longitudinal axis, A value of 1 fixes the yoke in this axis - they seem more like 'rigidity' values than calculated values for inertia. So i guess it has been scaled from 0=no restraint to 1=totally restrained for each axis.

Just guessing from observation

0.4, 0.8, 0.2 are the dimensions (in meters) of the bounding box: a 3d box that is assumed to have an uniform density and the specified mass (8 for the steering head).

The inertia is then calculated as (https://en.wikipedia.org/wiki/List_of_moments_of_inertia):

Code Select Expand

Ix = 1/12.0*mass*(dy*dy+dz*dz);
Iy = 1/12.0*mass*(dx*dx+dz*dz);
Iz = 1/12.0*mass*(dy*dy+dx*dx);

Where dx, dy, and dz are the values of InertiaBox. So bottom line: it's a "proxy" for the inertia of the element.

I really doubt it has anything to do with "rigidity" or "restraint".

But don't ask me why we have real inertia for the chassis and a box for other elements: I don't know.

[h106frp]

Thanks for the explanation, this is the sort of info that needs documenting for meaningful physics mods.

[HornetMaX]

Thanks for the explanation, this is the sort of info that needs documenting for meaningful physics mods.

Everything should be documented. Better if officially

[Yohji]

I'm still not understand "Inertia" and "inertiaBox" parameta well,,,, anyone can explain it? 

Inertia is ... weel, the inertia. What you don't understand ?

InertiaBox to me is just the inertia of the steering, don't know why it's called InertiaBox instead of simply inertia.

ex)  Inertia = 5, 3.4, 2.5
I know inertia's word mean, but what is first,second, and third parameta?
it's Diffusivity?

[h106frp]

x,y,z axis values or y,x,z or z,y,x i can never remember 

[HornetMaX]

Yep, inertia along X, Y and Z axis.

Careful about GPB convention about axes: best is to double check it in BikeEd, it seems to be left-handed ...

[Yohji]

I see, I'll tune it. thx.