AK71CutlassS

So I’ve been reading all the posts on sway bars
I have a 71 Cutlass S. Second owner. My dad bought it new.
it does. It does not have a rear sway bar. I did put boxed control arms already in the back(Hotchkis).

so from what joe was saying go with a bigger rear sway bar for rear. And smaller up front. corrects under steering

Front
Trans Am/firebird late 70’s is a bigger front. ??
looking to find soon . So if anyone has connections or where to get let me know.

Rear
looking for options that will bolt right up to hotchkis
i don’t like the axle clamp set up they have
if it needs to be bigger than front I don’t think hotchkis has one.

thanks in advance

joe_padavano

The car definitely wants as big a rear bar as you can find. Factory rear bars were 7/8". You can find 1" rear bars pretty easily in the aftermarket. Larger than that are out there but more expensive when you find them. I've been snapping up used 1 3/8" and 1 1/2" rear bars when I find them used at a good price.

The front bar is unfortunately driven by two conflicting requirements. As I've noted in other threads, the larger the front bar, the more the car understeers, so just based on that, you don't want too large a front bar. The conflicting issue is that the geometry of the 64-72 A-body front end really sucks. Limiting roll with a large front bar (and thus limiting camber changes due to suspension deflection) actually helps a lot. Trading off limiting camber change for increasing understeer is where that front bar diameter trade-off occurs. The right answer is to fix the front suspension with tall spindles or tall ball joints, but that's a discussion for another thread.

70Rocket

Suspension tuning basics do sat that a larger front bar increases understeer. But, that really isn’t always true. The underlying assumption is that your spring rate, shock valving, alignment, and geometry are already pretty close to optimum. At that point, a sway bar is a tuning device.

Joe’s point about a larger front bar helping handling in an A-body is a great case where you often increase front grip and decrease understeer with a larger bar.

As Joe pointed out, you are minimizing roll in the front and slowing / preventing a positive camber curve. That means you have a larger tire contact patch which equals more grip, which means less understeer.

Now, if you have already increased your spring rate, which also will help limit a positive camber curve, then the large front bar would probably induce some extra understeer. If your front springs aren’t overly stiff, the larger bar would help, not hurt.

On softly sprung cars that I changed from factory staggered (front tire narrower than rear) to a square tire setup (front and rear widths the same) I have often found that lap times were quicker and the car easier to drive by adding a much bigger front bar as opposed to softening the rear. This is not what you would think would be the case reading a suspension tuning book. How was the car faster when I choose to give up front grip and not increase rear grip with my bar selection? It was because my spring rate in the front was too low and as a result the car rolled to much in the front which impacted the camber curve and contact patch. The larger bar helped fix / mask the low spring rate.

As far as rear bars go, you may not like the chassis mount bars clamped at the axles, but you get much higher effective rates out of them compared to the OEM style bars. They are also tubular and save a fair amount of weight.