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Author Topic:   Front roll center location for 4 bar suspension
LITTLEMAN
Member
posted September 13, 2003 03:13 PM
Been working with 4 bar rear suspensions this year and was wondering where the best placement of the front rollcenter locations that has worked for you.Looking for left to right of center location.My thinking is the more left of center the better.Any thoughts would be appreciated.


dirtsquirt
Member
posted September 13, 2003 04:46 PM
This is a great question, RC MC has been getting a lot of press. All this talk of RC and MC, how to find it and so forth. Well to me its like the dog chasing a car, What do ya do with it after ya get it? No one ever gives the details of what RC MC location does to alter the feel of the car. Or how different types of tacks would perfer one RC location to another.


LITTLEMAN
Member
posted September 14, 2003 09:32 AM
I think of the front roll center location as a pivot point of a teeter tauter. and the wheels as the ends of it. The roll center location Has a lot to do with how easy the car rolls on to the right front.With a four bar suspension it lifts the left rear forcing the chassis to push down on the right front.The Roll center should be higher and to the right to fight off this force, I've built cars with the rollcenter about 3.5 inches up and a little left of center.Thinking about making a change.


MRB
Member
posted September 16, 2003 12:09 AM
I used a suspension program from chassis R&D by bob bolles.I measured all the suspension points with a plum bob ,level and a laser pointer.I also caled the balljoints manufacturer to get get the exact center of rotation for the ball joints.I Have been studying roll centers and their affect on the chassis for several years now.


MD
Member
posted September 17, 2003 01:44 AM
And what have you concluded? We are all adjusting the rear, what about the front. It seems it should be considered for different track conditions also.


LITTLEMAN
Member
posted September 17, 2003 07:43 AM
If your car genrally lifts the left front no matter what you do to the the rear suspension,then it is my opinion that the front roll center could be the cause of this.What I have found is:Moving the Rollcenter to the right will will make the chassis think it has a stiffer right front spring,also moving it to the left will make the car think it has a stiffer left front spring.But I need more data to prove my theory,Thats why I'm asking for feedback from the racers.Thanks


rocketwildone
Member
posted September 19, 2003 09:45 AM
Where would the roll center need to be to pull the LF off the ground.We have a 4 link that will not pull the LF off the ground no matter i try.