Comment:

Terry Fick

Interesting front suspension.  Bullock and Chamberlain did the same thing on the 76.  Who was first?  I have no idea.

Mounting the coil-overs inboard like this reduces unsprung weight.  Mounted conventionally, half the weight of a coil-over assembly would be sprung, half unsprung.  This design makes the entire assembly sprung.  As torsion bars took over on the front end the equation changed again.

Another advantage I see in this design is the lever loading the coil-over is working perpendicular to the spring.  Mounted outboard a coil-over must be inclined to clear the tire, adding a variable, or mounted inboard from the ball joint, adding a lever action and adding a variable.  With this design you can develop a chart of spring rates which will not vary with ride height changes making adjustments more predictable.

Today Indy car design is the same; an inboard coil-over with lever actuation of the steering knuckle.  My bet would be the Indy engineers are looking more toward aerodynamics but the advantage of lower unsprung weight is also significant.

Whoever came up with this idea really thought long and hard about it, and was way ahead of their time.

I’m inclined to agree with Terry about the advantages of the inboard koni’s on this Brenn Trevis car. I’m almost positive that it didn’t come from Trevis that way. I am however positive it didn’t stay that way.  The trouble with the inboard set up is it only had advantages on the drawing board and not the race track. I know there were quite a few cars around in the early days of coilover suspension that tried it. The Profile cars of Buzzie and Wayne (00 & 00jr) come to mind first. I remember it on the Chamberlain 76 as well but that may have been with A frames. Sooner or later the guys that tried them went to outboards. For some reason the advantages of unsprung weight and better motion ratio’s never showed up on the track.

Not to get off subject or anything but we could do a whole section on the different front and rear suspensions on the Brenn Trevis cars of the Ploski era. Inboard, outboard, front sway bar, no sway bar. Rear leaf springs came from Trevis but I saw rear coilovers as well at times. No matter what they tried, that 24 found victory lane. When Mr Brenn came to the Modifieds in the early 70’s he brought a lot of knowledge with him. Not to mention a few very smart guys that worked on his open wheel cars.  Bill Brown being one of them.