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

  • Context: Automotive 
  • Thread starter Thread starter Benfish65
  • Start date Start date
  • Tags Tags
    Car Micro Roll
Click For Summary

Discussion Overview

The discussion revolves around the concept of roll centers in a 600 micro sprint car, specifically addressing whether it is feasible to have different roll centers from the front to the rear of the vehicle. Participants explore the implications of roll center positioning on vehicle dynamics, particularly in the context of racing on oval tracks.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant questions the possibility of having two different roll centers from front to rear, indicating a struggle with the car's performance throughout the racing season.
  • Another participant raises a concern about the alignment of the roll center line down the middle of the car, suggesting it should be centered and consistent from front to back, but notes a discrepancy in their car's setup.
  • A different participant posits that if one roll center is off-center, it could lead to a "crooked" roll axis, potentially affecting weight transfer and handling characteristics when racing in one direction.
  • Another contribution discusses the expected offset of the rear roll center in a rear-wheel-drive car for round track racing, suggesting that the rear roll center should align with the car's weight distribution.
  • One participant mentions that the front roll center should also be offset to aid steering, and notes that changes in roll center height can occur during vehicle dynamics such as diving and rolling.

Areas of Agreement / Disagreement

Participants express differing views on the alignment and implications of roll centers, indicating that multiple competing perspectives remain without a clear consensus on the correct setup or its effects.

Contextual Notes

There are unresolved assumptions regarding the specific suspension setup and its impact on roll center behavior. The discussion also reflects varying levels of familiarity with suspension theory among participants.

Who May Find This Useful

Individuals interested in race car dynamics, particularly those involved in micro sprint racing or similar vehicle setups, may find this discussion relevant.

Benfish65
Messages
2
Reaction score
0
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!
 
Engineering news on Phys.org
http://www.onedirt.com/tech-stories/suspension/finding-your-center-finding-your-front-and-rear-roll-center/
 
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.
 
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.
 
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.
 

Similar threads

Do Front and Rear Axles Roll Differently in Independent Suspension Systems?
  • · Replies 25 ·
Replies
25
Views
13K
  • Sticky
Automotive Race car suspension Class
  • · Replies 2K ·
60
Replies
2K
Views
866K
High School Solving Special Relativity Equation: Rail Car Thought Experiment
  • · Replies 3 ·
Replies
3
Views
2K
Woodworking: How I Built My Own End Tables from Scratch
  • · Replies 42 ·
2
Replies
42
Views
7K