Consensus on big bar/soft spring?

[bergers59]

I'm trying to make a decision whether I want to go big bar/soft spring, or soft bar/stiff spring. From the research I've done, I've mostly found articles pertaining to late model asphalt cars rather than autocross. From what I can understand, soft springs are good for rougher surfaces(parking lots for autocross?) and making the tires work. I intend to run c prepared(slicks) and maybe a few 200tw events. Car will be 80% at track, so ride quality is of little concern. It seems as though BBSS requires different geometry(less camber change) to accommodate increased dive, and more testing/tuning to setup, is this true? I understand its a subjective question, but which setup is best for my application?

[Rod P]

Originally Posted by bergers59

but which setup is best for my application?

that choice is mostly decided from training and driving style...I have driven and raced both in other cars for testing

[BMR Sales]

Originally Posted by Rod P

that choice is mostly decide from training and driving style...I have driven and raced both in other cars for testing

I agree. I like a RaceCar stiff, but that is not for everybody!

[bergers59]

So one isn't faster than the other? Why are more people switching to a BBSS setup recently?

[SSLance]

There is a big long explanation as to why that Ron Sutton I'm sure could explain better than I, but in a simple form...having a high travel setup lets one configure the geometry to work best in all areas of a turn and the straights as well.

With a super stiff spring setup, the static geometry is what it is pretty much all of the time. You dial in camber to help the outside front tire contact patch, but completely give up the contact patch on the inside front tire.

With a front suspension that travels, you can maximise the contact patch on both front tires in a turn. Aren't two tires gripping better than one?

Watch this video to see how well a soft spring\big bar setup helps make a G-Body turn.

[bergers59]

point definitely taken, but could you not compensate for the stiffer spring rate car by making the dynamic camber change larger for a smaller distance of travel?
Another thing I just thought of, since I intend to run c prepared and I intend to get the car as low as I can, would running a softer spring rate and higher travel limit my static ride height setting?

[mfain]

Originally Posted by bergers59

I'm trying to make a decision whether I want to go big bar/soft spring, or soft bar/stiff spring. From the research I've done, I've mostly found articles pertaining to late model asphalt cars rather than autocross. From what I can understand, soft springs are good for rougher surfaces(parking lots for autocross?) and making the tires work. I intend to run c prepared(slicks) and maybe a few 200tw events. Car will be 80% at track, so ride quality is of little concern. It seems as though BBSS requires different geometry(less camber change) to accommodate increased dive, and more testing/tuning to setup, is this true? I understand its a subjective question, but which setup is best for my application?

I've been watching this thread some, and I decided to throw in a couple of cents worth. OP, you are right in that the BBSS (high travel/low roll) works because of the geometry changes the high travel produces - for example, caster gain that results in correct camber movement for BOTH tires, not just the outside tire when they are turned. After studying Ron's posts (and many other sources on the subject) and talking with Ron personally, I made the move and cut several thousand dollars of C6 suspension out of my unfinished project track car and started over. To make a long story short, there isn't a piece of the car forward of the firewall that wasn't cut, moved, or massaged to accommodate big tires traveling 4 inches in compression (with proper geometry) and still being able to turn without hitting something- frame rails, front cross-member, sway bar mounts, inner fender wells. etc. I guess I'm saying that your decision on whether or not to go BBSS should involve careful analysis and preliminary design work to see the extent of the changes required and to see if all of the effort and expense is worth it to you. It is more than changing the springs and sway bar on a production-based vehicle. Good luck with your project.

Pappy