This graphic illustration...
This graphic illustration explains how much Ackermann is required to cause both front wheels to track correctly through the turns. The calculations were done with a very sophisticated and accurate coordinate geometry software program. The difference in steering angles for the front wheels are very small and reinforce the fact that little or no Ackermann is necessary for normal short-track racing.
We have made the statement in the past that we don't see track records falling from the use of the BBSS setups. OK, some have, but there aren't any cars out there going a half a second faster with the BBSS setups. And that doesn't mean it works everywhere.
We have proven that the BBSS setups are not meant for all racetracks. In general, the higher the banking at the track, above 10 degrees or so, the less effective the BBSS setups will be. If your track is above 12 degrees of banking don't even think about it.
Tracks with a rough surface and/or large transitions in banking angle from the straight-aways to the turns are hard to manage with the BBSS setups and you might be better off, and more consistent, running more conventional.
The tracks where these setups shine are the flatter and smoother tracks and the long "super" speedways like Kentucky or Nashville Super Speedway (not the Fairgrounds). Gateway International Raceway is another good one and I'm sure similar setups have been used successfully at the now defunct track in Lakeland, FL.
Out west, we might see the BBSS setups at tracks like Phoenix or Evergreen Speedway. The longer and faster tracks will benefit from the added aero effect to provide more overall grip adhesion for faster turn speeds. On 3/4- to 1-mile tracks, that added speed can add up to several tenths lower lap times.
Slotted steering arms allow...
Slotted steering arms allow us to dial out the Ackermann in our front end. This works as long as we only turn left as in asphalt racing. Dirt car Ackermann adjustment is done differently.
I recently heard from a team that had won the last two year's championships with a more conventional setup. The team now wants to go to the BBSS setups for next year. I can't understand that reasoning, other than the fact that racers just can't stand still. I preach the idea that you can never just maintain, but at the same time, don't shoot yourself in the foot either.
The choice of setup is entirely yours, so chose your setup based on need. If you're winning a lot with conventional setups, you can experiment during a test session like we did, but not once the season starts. There's not enough time to properly evaluate the difference.
Watch your shock travels at the RF when using very soft springs. If the spring binds and/or the frame contacts the track, the car will move quickly toward the wall. Make spring changes in a progression rather than a one-step change. Adjust the shocks to control the transition. Add a little crossweight with each change to maintain the neutral handling.
Once the car is neutral, get good lap times up to 15 to 20 laps and then immediately switch back to the conventional setup and make another run. See which one feels better to the driver and which one is faster, especially for longer runs. Compare those times with the usual lap times everyone else runs. Make a choice and go with it.
If you decide to go with the BBSS setup, go all the way. Do the very soft front springs, install a larger sway bar, increase the RR spring rate by at least 200 pounds and adjust your shocks to complement the setup.