I am planning to add a rear sway bar and box the lower control arms on my 69 convertible. For a few dollars more I can buy the 1" bar rather than the original 7/8" bar, so I want the one that will give me the best results.

Is there any downside to having the larger bar or will it throw off the handling? Would it require a larger front bar or am I overthinking this?

Ed

Ideally you shouldn't need any rear stabar. Going too big if you decide to run one will induce oversteer, a condition that an experienced driver could deal with, but on the street you may not like it.

Yep, it is good to match the sizes of the bars. I once put a rear bar on a car and did not upgrade the front bar. It did not really get any oversteer, but it would lift the inside rear tire on tight turns. Not good.

I have a 1-1/16 inch bar on the back of my '65 coupe. I've never had a problem with oversteer. I coupled it with a 1-1/8 inch front bar and it drives very balanced.

A lot depends on the size of the front bar you have. What size bar do you have up front? Is the car lowered? Do you have rubber or poly suspension bushings? What size tires and wheels are you using?

Car is not lowered, all poly bushings, 15 x 7 with 225.60 tires, and a small block. Bar up front is the smaller GM offering - I think it is 1 1/8" but would have to measure to be sure.

If it can produce the oversteer problem then its not worth the risk, otherwise I will have to increase the front one as well - right?

Ed

With 1-1/8 up front, a 7/8 bar out back would be a good match for improved everyday driving. Even the one inch bar out back wouldn't be too much with that big of a bar in front.

The front should always be bigger than the rear. I have a 1-1/8" front and a 1" rear on my 66 driver. Works golden.

Where can you find a 1" rear bar?

I know Muscle Factory and Addco have them, I'm sure there are others.

>>Originally posted by eduardo69chevelle:
[QB] I am planning to add a rear sway bar and box the lower control arms on my 69 convertible. For a few dollars more I can buy the 1" bar rather than the original 7/8" bar, so I want the one that will give me the best results.
Is there any downside to having the larger bar or will it throw off the handling? Would it require a larger front bar or am I overthinking this?<<

You should measure front to be sure of what size you have.
A convertible is a bit heavier so might benefit from heavier bars.
I found that in a 6 cyl 64 Malibu that the big front bars were maybe too much.
Ended up with the stock bar in polyurethane bushings and 1" rear bar. I liked it.
As with the OEM the aftermarket probably is hesitant to give you a car that doesn't understeer.
IMHO The aftermarket is increasingly litigation conscience so are less and less willing to hand out advice that's not written in stone [or on the "tech's" :confused: computer screen].

You can find on the Global West site a suspension setup, using their parts, that uses no rear bar at all!
http://www.globalwest.net/index.html

Justin, OPG has the 1" rear bar on sale for $67. My front bar is around .940" so I decided to go with the 7/8 bar from GMPartsDirect.com for $62 (shipping only $12).

Ed