Dirt micro sprint car -- two different roll centers from front to rear?

[Benfish65]

Hello everyone!

New here to this forum!

My question is...I race a 600 micro sprint here on the east coast.

My car has a front and rear panhard bar. The frame mount for the rear is located on the outside of the right frame rail. The frame mount for the front is located on the inside of the right side frame rail.

Is it possible to have two different roll centers from front to rear?

I struggled with this car all year and I'm trying to find answers!

Any help will be greatly appreiciated!

 

[jack action]

http://www.onedirt.com/tech-stories/suspension/finding-your-center-finding-your-front-and-rear-roll-center/

 

[Benfish65]

Yes I agree but what about the roll center down the middle of the car?

If I'm looking from the top of my chassis down there is a line down the length of the car from front to back...shouldn't this line be in the center of the car? Shouldn't it be the same from front to back?

Right now this line is different from front to rear...it's almost center on the front but the rear it's moved over to the right about 6". I don't think this is correct.

 

[jack action]

If one of your roll center is off center, then your roll axis is "crooked".

Although I'm not familiar with your particular suspension and car, I assume you are racing on an oval, always in the same direction. Putting the rear roll center on one side would affect weight transfer F/R distribution. My guess is that in your case, it helps loosing up the rear end to initiate drifting when entering a curve.

 

[Ranger Mike]

drawing a line form ft. to rear rc. the lone will NOT be parallel to the cars center line unless you are racing a road course.
if you race a rear wheel drive car for round track racing you will have the rear RC offset. ifin you have 56% left side weight I would expect the center of the rear end to be located 56% to the left side. you should have no deviation of the left to right rear RC location in bump. you can expect slight RC height change in bump.
ft. RC should be offset to the right to help steer the car. ( see race car suspension class to find out why). You can expect ft. rc to change in dive and roll but would be a straight vertical change if you have it set up correctly. the ft. rc will be lower then the rear rc if you have front engine rear wheel drive car. again see race car suspension class to find out why.