Lateral-g Forums - 4 link / ladder bar not for street handling?

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You're right, introducing an axial rotation DOF in each link will still leave the parallel 4 link overconstrained, but it will remove one additional overconstraint in the case of poly bushings at both link ends, without the NVH and wear issues of heim joints.

Agreed, but only if the things are actually allowed to rotate under load, which is not clear to me from the pictures I have seen, I have not seen one in person. I don't see any type of lube port, so if it is a metal-metal contact, it will only rotate until galling takes over. No way to fit some form of bearing, unless there is something that I have never seen before (entirely possible), possibly there is some form of slippery shim, like delrin or the like? No idea. Doesn't matter, like we both agree, the compliance of the rubber is enough.

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Make no mistake, all suspension designs are "compromised" from the start.

Completely agree. We have several compromises in our setup as well, I will be the first to admit it, and have to any and all potential customers/interested parties. We wanted to make a system that WILL perform well on the track, not one that "COULD" if everything was just "so." A lot of research went into our decisions, and a lot of input from folks that race these types of cars. Further, one key area of importance was that it had to have perfect street manners as well, and drag strip, etc. This is not to say you just slap our stuff on and you're ready for the 24 Hour Daytona race.

High speed stability was the main attribute we went after. This means that on a road course, nothing sudden or surprising will sneak up on you, or at least, relative to other designs, it is far, far less likely to. Neutral roll steer, and a sufficiently long SVSA were two of the very first and main design requirements, the first to keep the rear end from steering the car through sweepers, etc (ever driven a fork lift? If so, you can get a feel for how little input is needed to have a pretty dramatic tail movement, not good). The second was to minimize the opportunity for brake hop in hard braking zones, which is a big deal, especially if you drive where there are large heavy things to hit. Last, trying to get a good amount of Anti-squat was an exercise while trying to balance the other two. We are very happy with the results.

Perhaps I should stress a point here. We are interested in high speed stuff, as I mentioned. There is NOTHING about our setup that has any downside in a street driven car, from a performance standpoint (we use a rubber bushing on one end of the trailing arms for folks that like a quieter ride, or will offer all heims). A good road race designed setup can work extremely well on the street. However, a good street setup won't necessarily work well on the track, and in almost all cases, they don't. The performance requirements for the track are a lot more difficult to attain than those for a street driven vehicle.

I love writing about this stuff, and I love it when folks are interested in providing alternative views, learning, challenging ideas constructively, it is educational for all. And from the business side, our approach is that an informed customer will make the best decision for their application, we get frustrated when suppliers just say "it's good, you'll like it." That's not how we want to do things.

Mark