Originally posted by Rob Hochberg
I used the roll center bridge, but it made the car feel really squirrely on power, and there was signicantly less bite in the rear until about halfway into the race. I ended up taking it off, because it was screwing me up so bad. Can anyone elaborate on how exactly the roll center bridge should be used to tune the car?
It lengthens the upper link. This does two things:
1. Changes the roll center and the rate of change in the roll center in the corner. This will make the rear end roll deeper. This will slow the transition of the rear end in esses since it has further to recover. The rear end will have more grip mid corner as the rear end settles down and weights up.
2. You will have less camber gain as the suspension compresses. As the car rolls over this can change the camber from negative to positive, so you loose traction. To compensate you will need to run a stiffer spring to reduce roll or run more negative camber or both.
If you where squirely on power, it depends on where in the corner you applied power. If your camber is around -1.5 to -2, your rear end should actually stick harder then the front since more mass has transitioned to the outside rear corner becuase of the longer link.
You might also be saucing the tires wrong, since traction came up mid race.
Or the tires started to cone which will give more effective negative camber mid race.
If your front links are signifigantly shorter then the rears, your squirleyness might be caused by the front end transitioning much faster then the rear, and so having more traction late in the corner.
Long links will roll deeper (and slower) and transition more mass.
Angled links will limit how far the roll is, more parallel = deeper, more angled = less roll
Also need to remember about camber gain too!
This is all realative from front to back. This is also how you can change the cars behavior from entry, mid to exit of the corner.
I like my car to over steer on entry, neutral to push mid, and neutral on exit (I also play with damper, toe, springs, caster, droop etc. to do this)
No simple answers unfortunatly..... but then this is why touring cars are so cool (for me anyway).