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Author Topic:   Roll Centers???
General
Dirt Maniac

Total posts: 151
posted November 24, 2001 08:17 PM
How do you meausure roll centers? We tried to come up with a way to measure roll centers on our stock stub car, but were not successfull. Maybe if I had a better understanding of the entire concept. I'm afraid my S.S. book just confuses me.

LITTLEMAN
Dirt Maniac

Total posts: 130
posted November 26, 2001 09:48 PM
rolcenters are measured by finding the instant centers or connecting points of the upper and lower a's an imaginery line is drawn thru the balljoint centers and the inner mounting points of the a-frames at this point a line is drawn back to the tires center line and where they intersect each other is the rollcenter.

farmbilt
Dirt Newbie

Total posts: 2
posted November 26, 2001 11:08 PM
What is the correct rc for todays mods? With left frame height lower than right which offsets the rc to one side do you make left upper mount higher to put rc back in the center of the car and to keep both uppers at the same angles?

wfoondirt
Dirt Freak

Total posts: 242
posted November 27, 2001 09:43 AM
Typically on a dirt car a good starting point is 4" high and 2" to left

dirtsquirt
Dirt Full Roller

Total posts: 29
posted November 30, 2001 10:50 PM
Any more answers to farmbilts' question?

LITTLEMAN
Dirt Maniac

Total posts: 130
posted December 01, 2001 04:52 PM
Farmbilt,thats a very good question as far as roll centers go they depend on what your trying to accomplish with the roll of the front end moving the rollcenters left to right will affect how the front end springs feel the weight that is carried by them if the rollcenter is to the right the car will think it has a stiffer right front spring making it have more more travel on the right front with the same spring.moving the roll center to the left of center will make the car think it has a stiffer left front spring .raising the left upper a mount will move the rollcenter to the right and lowering the right front upper a mount will move the rollcenter to the right.placement of the rollcenter is really an imaginery point that designers use to make their cars react to the rear suspension and track width c.g. and total weight where the rollcenter ends up is really more important than the static placements.hope this helps

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