Cantilever on s197?

[Norm Peterson]

Anything that is between the spring and the ground is unsprung. Wheels, axle, and in the case of a pushrod setup, the pushrod and rocker. They can have some advantages, but reduction in unsprung weight generally isn't one of them unless you are talking a very large motion ratio rocker with a small, stiff, short stroke spring and shock (think indycar parts). Outside of something like a 5:1 rocker, with a spring that is 5X as stiff and a shock with 1/5 the stroke, you're going to gain unsprung weight.

That's kind of the way I see it.

Granted, there is less static weight being carried directly on the axle, but that does not represent dynamic reality, which is what you need to be thinking in terms of once you're actually driving the car.

It isn't possible to claim that the effective amount of unsprung mass gets reduced in a pushrod/pullrod suspension without having the actual mass and motion ratio math to back it up.

Chances are really good that in this case the trade-off ends up adding effective unsprung mass, and adding it up high where it will nudge the sprung mass CG up a tiny bit.

The benefits appear to be limited to freeing up a bit of real estate under the car for exhaust or other components, and it would be a bit easier to put the shock piston and rod on the unsprung side than it is to do so with conventionally-mounted shocks (I'm assuming that the total weight of the piston plus the rod and the weight of however much oil gets displaced is less than the shock body weight plus the weight of the oil that doesn't have to move). And the bling factor, for those who rank appearance high on the list of priorities.

I don't immediately see any benefit as far as how/where the suspension loads are fed into the main chassis structure. I'm not saying that there can't be any advantage here, just that if there is, it isn't obvious.


Norm