Raised roll center?

[Slush Monster]

I was recently reading that (The new vector power plant effectively
lowers the center of gravity,witch required the suspension engineers
to raise the sleds ROLL CENTER to maximize frontend handling.)Ok
what exactly is a sleds roll center? and what exactly did they do to
raise it? Just unsure what this means and would like to know. Any
ideas? THANKS

 

[LazyBastard]

If you look at the front of an RS and compare it to the front end of an RX, you will see that the RS has shorter spindles, and that the arms come out of the body at a steeper angle.

 

[Mikey]

Roll centre is basicly the point at which if you put a spear directly thru the center of the sled from bumper to bumper at a point that if you rotated it on the spear it would be perfectly balanced. By taking what LB said and adding the fact that now the centre mass is further from the ground that the effective roll center is now relocated.

 

[Slush Monster]

So than if I have this streight the roll center lowered with the new engine,
so yamaha wanted to raise the roll center back up so they redid the front
end. Does this mean the bumper height will be higher on the RS V.S. the
RX? Are they shooting for a certian height for the roll center off the ground? Or in relation to the rider?

 

[Traildemon]

No, the "roll center " is a theoretical center of mass found by measuring through the "plane" of certain suspension pivot points. it does not necessarily mean a sled is physically higher or lower. The shorter spindles on the Vector may give it a lower center of gravity, so they may have had to raise the roll center back up by changing other components :wink: Wonder if the short spindles will fit an RX-1 :?: :idea:

 

[LazyBastard]

The actual vehicle height *appears* identical, the relative height of the inside a-arm pivots is higher on the RS with respect to the outside pivots (at the spindles). Changing the spindles won't change the COG. The adjustment to the roll height has to do with the relative height of the mount points of the a-arms on the inside and outside. If you look at a *properly* setup RX, you can draw a line straight through the a-arms on both sides without hitting an angle - they are both parallel to the ground. On RS, they are angled pretty steeply. Having the a-arms on the steeper angle will tend to hold the body straight. If it wasn't nearly 1am, I could probably remember enough trig to figure out how much. Expect RS to ride more flat.

 

[Slush Monster]

Ok I get it. Won't the a arms not soak up the bumps as well
at a steeper angle? Or do you just change the springs somewhat?