1" vs 1 1/8" Sway Bar

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Howdy everyone,

Been looking at getting a better sway bar for some time now. Right now CJ Pony Parts has a 1" bar for $119 right now which seems like a good deal. Wondering thoughts on how big an improvement this might be over stock and how better / worse it would be over a 1 1/8" bar? Not looking to track the car or anything, but definitely would like to improve handling and drivability. 

Thanks!

 
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A 1" sway bar provides an increase in cross-sectional area, over the stock 3/4" sway bar, of 78%. The 1-1/8" sway bar provides an increase in cross-sectional area, over the 1" sway bar, of 27% and over the 3/4" sway bar a cross-sectional area increase of 125%. 

 
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It's going to be difficult to find someone with real world experience that has used both a 1" and a 1 1/8" sway bar on the same car and can tell you their impressions. I have no personal experience with this, but Opentracker Racing ships 1 1/8" sway bars for their "street performance" suspension kits, that may say a bit of what people that deal with this on a daily basis think. You might want to call them, or shoot them an email:

https://opentrackerracing.com/

 
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OK thanks. Sounds like either will be way better than stock and bigger is probably better. I'll think about if saving a few bucks is worth it. 

 
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You didn't say front or back sway bar, I assume front. 

Like Jpaz, I to have the Adcco 1 1/8th up front and the new correct fitting Addco 990 bar at the back. Handling is waaaaay better, but then I have new Eaton Springs "Boss springs" on the rear and the front was rebuilt a couple of years back. My usual go-to store for my parts is NPD. I don't trust CJ Pony Parts any more.

 
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Thanks guys. Yes, this is for the front, link is in the first post. I hear you on CJP, one order and a few parts are here the next day, the others 2 months later and nothing letting you know that's the case. More than once got parts in, set aside time to work on the car on the weekend, get the thing ready start taking things apart and didn't bother to open the box only to realize the little crap I didn't need right away is in there but the stuff I needed isn't, only to show up weeks later. In this case CJP is mostly because of price. I only have so much to spread around so $120 to cross that off the list seemed like a good deal.   

Front end is mostly rebuilt and the rear is new shocks, new bushings, old springs for now. No sway bar back there at the moment. 

 

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For what it’s worth, I have a 1” bar on my gray ‘72 that came with a suspension kit I bought a few years ago. I like the bar fine, and do think it is a big improvement from stock. Problem is... it is so big an improvement from stock that you need to replace or add a rear one also, otherwise the stiffness in front will make the back feel unstable (ask me how I know).  
 

So here is where it gets a bit complicated. You really want a little bigger bar in front than back for stability. Consensus is around 1/4” difference in diameter front to back for our cars. The stock bar in rear is 1/2” (and 50 years old) so therefore too small/weak for the 1” bar. The best rear bar is likely the new version of the addco mentioned above, but I believe it is 7/8”. So that means only 1/8” difference to your proposed 1” bar, which is closer than most like. 
 

I had kind of a hard time finding a 3/4” rear bar to get a 1/4” difference from my 1” front bar. Since my car had no rear bar on it when I got it, I ended up going with a different addco model (for those with no stock rear bar), which is 3/4” but uses an aftermarket mounting assembly on the leaf springs themselves just behind the perch, as opposed to the plate under the perch as it was on factory-equipped rear anti-sway bars. 
 

So my recommendation is that if you have, or want to add, a stock-design rear bar but in 7/8” thickness, then buy the 1 1/8” front bar.  If you want the 1” bar, buy the addco “aftermarket style” rear bar, which is 3/4”. I strongly recommend a rear bar of some kind with either front bar choice. Believe me, a modern thickness front bar installed alone makes the front feel great but the back feel irritatingly wishy-washy.

 
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For what it’s worth, I have a 1” bar on my gray ‘72 that came with a suspension kit I bought a few years ago. I like the bar fine, and do think it is a big improvement from stock. Problem is... it is so big an improvement from stock that you need to replace or add a rear one also, otherwise the stiffness in front will make the back feel unstable (ask me how I know).  
 

So here is where it gets a bit complicated. You really want a little bigger bar in front than back for stability. Consensus is around 1/4” difference in diameter front to back for our cars. The stock bar in rear is 1/2” (and 50 years old) so therefore too small/weak for the 1” bar. The best rear bar is likely the new version of the addco mentioned above, but I believe it is 7/8”. So that means only 1/8” difference to your proposed 1” bar, which is closer than most like. 
 

I had kind of a hard time finding a 3/4” rear bar to get a 1/4” difference from my 1” front bar. Since my car had no rear bar on it when I got it, I ended up going with a different addco model (for those with no stock rear bar), which is 3/4” but uses an aftermarket mounting assembly on the leaf springs themselves just behind the perch, as opposed to the plate under the perch as it was on factory-equipped rear anti-sway bars. 
 

So my recommendation is that if you have, or want to add, a stock-design rear bar but in 7/8” thickness, then buy the 1 1/8” front bar.  If you want the 1” bar, buy the addco “aftermarket style” rear bar, which is 3/4”. I strongly recommend a rear bar of some kind with either front bar choice. Believe me, a modern thickness front bar installed alone makes the front feel great but the back feel irritatingly wishy-washy.
+1, great description. 

 
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@Lazarus That's great feedback and exactly what I was looking to find out. And I was actually wondering how this would behave with a bar on just one end I don't have one round back. Didn't know if it would be just not as good or maybe be uneven. You answered that. Always planned on adding a rear at some point, but will go ahead an do that at the same time. So I'll probably do the 1" bar and the 3/4" Addco rear bar as you mentioned. Seems like a pretty cheap way to make a nice improvement in handling. 

Thanks much for the great feedback.

 

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I went with the 1-1/8" front and a 3/4" rear and love the way the car drives and handles. A good set of shocks and modern alignment settings will add a ton to the overall drivability. Just my opinion and experience. 

 

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I went with the 1-1/8" front and a 3/4" rear and love the way the car drives and handles. A good set of shocks and modern alignment settings will add a ton to the overall drivability. Just my opinion and experience. 
The quarter inch minimum difference is not a hard and fast rule, by any means. It just seemed to be the consensus. I am definitely not sophisticated enough to tell the difference between cars with 1/4” vs 3/8” difference front to back.  

The big thing is you don’t want too big of a difference and you don’t want parity either. In the case of too big of a difference the rear feels wobbly in a turn. In the case of equal bars (or in an extreme case where the rear is stiffer) you can have dangerous steering/traction issues in turns. 

All that said, I think the 3/4” addco rear setup cost me less than $100 on sale on Summit or Jegs. The list price is still only $145 on addco’s website. So if someone is buying a front bar, there is at least one option for the rear that is well worth the additional investment.

 
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Thanks for the feedback. I went ahead and bit on the 1" bar from CJP. I ordered it last night and it just arrived this morning. That place is nuts, things either get here in hours or in 2 months. I'll be picking up the Addco 3/4" bar either direct from them or might wait to see if I can find a Black Friday sale. 

 

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@Lazarus That's great feedback and exactly what I was looking to find out. And I was actually wondering how this would behave with a bar on just one end I don't have one round back. Didn't know if it would be just not as good or maybe be uneven. You answered that. Always planned on adding a rear at some point, but will go ahead an do that at the same time. So I'll probably do the 1" bar and the 3/4" Addco rear bar as you mentioned. Seems like a pretty cheap way to make a nice improvement in handling. 

Thanks much for the great feedback.
Our Mach 1 has a 1 1/8 up front and 7/8 out back.  Feels like a totally different car than it was with stock sway bar up front + no sway bar in the back.  For me and my style of driving, this feels just right.

I'm no suspension engineer, but from what I remember...  The larger the front sway bar, the flatter the turn entry (less lean - this is what sway bars do) and the more the car wants to understeer.  The larger the rear sway bar, the more the car wants to oversteer.  As mentioned elsewhere in this thread, it's all about finding the right balance for the type of driving you do.  

If you want to experience this first hand, remove your front sway while leaving your rear.  Take her for a spin and you'll see how the tail wants to come around (oversteer) on every turn.  This is great if you're feeling nostalgic for Malibu Gran Prix, but IMHO a bit too much work for a daily driver  :classic_cool:

 

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