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3/4" Rear Sway Bar Opinions

1766 Views 12 Replies 5 Participants Last post by  AdamCali65
Hey all,

I am contemplating a 3/4" rear sway bar. I have on the '65 subframe connectors, a 1 inch front sway bar, gas a just shocks all around, 1 inch 620# lowering springs up front and 1 inch lowering leafs in the back, etc. I am hoping for your opinions on running a rear sway bar on a car that is driven only on weekends (not a daily driver at all), I dont care much about stiffness just fun, sometimes I take the car to the canyons, and I am looking for more performance and stability in the rear end. What do you all think?

I have heard that a rear bar can induce oversteer but if the front and rear are matched (like 1 inch up front 3/4" in the back) it works out nicely.

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The vast majority of leaf spring cars do not need rear sway bars. What sway bars actually do is increase weight transfer by lifting the inside wheel, which is exactly what you don't want in a rear-wheel drive car. Only when the body roll is excessive, should you install one. If you have bad understeer, and you install a sway bar, you just lower the rear end's handling ability to match the front. You're probably best off performing a Shelby drop with improved caster. That will help raise the front end's handling ability to match the rear.

Still, if you do want a rear sway bar, I'd stay away from the one that mounts the bar on top of the axle. It seriously compromises exhaust clearance, and I've had my exhaust torn out by it on a couple occasions. Get the adjustable Shelby style one that mounts the bar to the chassis, then you can fine-tune it to your car. Or there's this TCP sway bar that mounts under the axle so it won't interfere with the exhaust.
Depending on your driving abilities, some looseness is actually faster. I had a similar combo for quite a while, with the 620 springs, 1-1/8" front sway bar, and a Shelby drop. My 3/4" bar helped bring the handling more towards neutral from understeer, but it still felt a bit sloppy. As a rule of thumb, adding rear bar increases oversteer. There's really no way around it. If you're oversteering already, then a rear bar will only make it worse.

I might suggest looking at your wheels and tires if you want to improve responsiveness and handling. In your case, 16" or 17" wheels with 215 width tires in the front on 7" wide wheels and 245 width tires in the rear on 8" wheels would help improve response and rear end grip dramatically. Otherwise, there aren't many good ways to improve a leaf spring suspension. The KYBs are probably alright for occasional spirited driving, but I'd personally recommend Konis, especially adjustable ones, for driving near the limit. Bilstein is also a good budget option, but they're not really adjustable. I found that the KYBs don't damp nearly enough for any serious performance driving. Right now I have KYB Gas-A-Justs in the front and Koni Yellows in the rear, and the front end wallows over bumps while the rear stays controlled. Many racers will tell you that next to tires, shocks are the most important part of a performance suspension system.

That Addco bar is what I had, and it does mount to the axle. Perhaps my exhaust was bent poorly, but the removal of 1 1/2" of clearance above the axle caused it to impact the exhaust on some larger bumps, which pulled the hangers free.
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If you do decide to do the sway bar, just approach the limits gently. The limits may be lower with the bar, so just be wary. If you can find an adjustable bar, or a 5/8" bar, use that instead of the 3/4" Addco. I do think that a rear bar does improve responsiveness in the rear, so if that's what you're going for, it should do the job, but leaf springs have their limits for responsiveness.
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