IRS suspension

Color me ignorant, but what is ZRS?

[GS guy]

Originally Posted by vwdevotee

Color me ignorant, but what is ZRS?

It's a swingaxle based suspension that uses zero roll resistance at the rear, but makes the swinger behave much like a solid axle car. It allows the rear-chassis to roll without resistance - but at the same time keeps both tires planted flat on the ground - regardless of roll angle. All vehicle roll resistance is controlled up front, with a standard sway bar. SOP on current formula Vee designs, though it was created back in the late 60's (or maybe before).

Since the roll resistance is all controlled by the front tires and sway bar, doesn't that put a huge strain on the outer front tire? Doesn't a ZRS car push bad in the corners?

[GS guy]

Originally Posted by vwdevotee

Since the roll resistance is all controlled by the front tires and sway bar, doesn't that put a huge strain on the outer front tire? Doesn't a ZRS car push bad in the corners?

You'd think it would. I don't know anything about the dynamics of driving a ZRS equipped car, only the concept of how it works and intent. Apparently it works very well since it's been used for over 20 years in Formula Vee. The modern version also uses a different trailing arm (leading arm?) axle positioner that minimizes toe changes in bump/rebound.

I've noticed though that a lot of archaic technologies are still used in racing series, but they are typically there because of some rule. I would say that, while the ZRS setup might keep the tires at a constant angle to the ground, since Porsche abandoned it very early on for the sake of performance, there are much better geometries.

[GS guy]

Originally Posted by vwdevotee

I've noticed though that a lot of archaic technologies are still used in racing series, but they are typically there because of some rule. I would say that, while the ZRS setup might keep the tires at a constant angle to the ground, since Porsche abandoned it very early on for the sake of performance, there are much better geometries.

Agreed! The unequal length A-arm suspension rules - it's a winning design and all the highest level performance cars utilize it (when they could do anything they want, with virtually unlimited budgets!). Only the computer controlled "active" suspension of the F1 cars from the 90's (was it the 90's?) surpasses the tried and true classis a-arm coil-over design - and it was still a version of the A-arm layout. But dealing with the classic VW Beetle, you're somewhat limited by what advancements you can employ. Utilizing applicable Porsche components seems to the "ultimate" at this point. Unless you want to totally re-engineer the chassis.... Pretty much exactly what I'm doing with my Deserter buggy.

What are you doing to your Desserter? I've read a lot of stuff on here that jas people designing their own a arm suspensions. I figure that if they are ambisous enough,than more power to them.