[scripts]

I'm getting ready to order some more parts and was wondering what the difference between the two sizes of front way bars are?

What size would you recommend?

I plan on putting in 620 springs (maybe opentracker perches later) with the sway bar.

 

[TcodeV8]

The difference is 1/8"






























, well it is!

 

[scripts]

I guess I should have phrased that differently . What is the difference handling and ride quality wise.

 

[TcodeV8]

I can't say b/c I haven't had BOTH on my car, only the 1" but the one 1" is a nice improvment over the stocker... I can't imagine the 1 1/8" being that much better, but hey, maybe it is??

 

[66coupe289]

I have heard that a 1 1/8" bar is too stiff, especially for a street car. 1" is as big as I would go.

 

[blksn8k]

Any chance there could be oil pan clearance issues with the larger bar?

 

[scripts]

I highlt doubt that there would be any clearance issues or they would make 'em differently or have a disclamer.

 

[slim]

As I recall the 1" sway bar was part of the optional handling package on the '65. 1 1/8 would be about 25% stiffer. Of course the overall front structure has to be solid enough or you just increase the twisting/stress.

 

[tubo3]

I have a 1 1/8that seems to work fine for me, though I've heard many times the 1" is the prefered size.
I do very highly reccomend that you rethink using 620 lb springs. That is unless your planning a track only car. they are way too stiff, IMO. I like a firm no sway ride, yet have found the best handling suspension to use moderate springs & stiff shocks. Check out Pro-Motorsports 64 1/2 to 66 Front "Progressive Rate" Coil Springs. 350 to 480 lbs/in. They may sound wayyy too soft, BUT THEY AREN"T. http://www.pro-motorsports.com/?page=prod_frontcoilsprings They work well with the KYB Gas-A-justs, though I'd like to try them with the Bilstines that rumor has said are available(rumor-meaning I dont know where to find 'em) "Progressive Rate" Coil Springs ride is un-harsh over bumpy surfaces, yet hug the corners when you get more agressive. Roller spring perches also work well in combination with them.
I think too mny Stangers were influnced by advertisements in M&F and MM magazines, and have unadviseadly come to think of harsh 600-620 springs as necessary to handle well.

 

[monkeystash]

If you stay with the 620s go 1 inch, and if you go softer on the springs then go 1 1/8.

 

[roadracer]

The 1 1/8" is about 60% stiffer. The stiffness is proportional to diameter but it's non-linear.

I have both and would reccomend the 1".

 

[Ronstang1966]

I agree with Tubo65fbEFI. Most people go way to stiff on the suspension on these cars because they just don't have a reference point. I found out by accident. About 20 years ago I decided to put new coils in the front of the Shelby. I thought I bought the right springs but the idiot sold me 65/66 GT springs instead which are closer to 500 lb/in instead of the 620s that most people use.

I didn't realize I had the wrong springs and with the Koni shocks and the 1" sway bar the car handled terrifically. It was a nice compromise between handling and ride. The car didn't lean and was great on bumps and generally hugged the road very nicely for a 20 year old car (at that time).

Then when I had the car apart for something else I realized the springs were the wrong ones after measuring them. I had seen a bin of 620s at the local Mustang place and mine were not that big so I went home and measured them. Sure enough I had the wrong springs. I bought a new set of the correct springs and to my dismay the car actually handled WORSE with the 602s over the 520s.

If you have good shocks I suggest you stay with 520 or less springs and a 1" sway bar as any more on the street is simply too much. The car tends to buckboard around turns with bumps with too stiff a suspension.

 

[obsidianspider]

I ran a 1" bar for years and it was a noticeable improvement over the stock bar. I can't comment on the 1-1/8" bar, but I think the responses from some of our members who have real racing experience say enough. JMHO, but get the 1" bar.

 

[mod9]

I have a 1 1/8" sway bar in my 69. It also has a coil over set up with 450 pound springs. The car is way to stiff in the front. I am going to replace the front springs in the car with a set of 375 pound springs and try it. If that does not work I will go down to a 1" sway bar.If it were me I would go with the 1" bar.

 

[TheShagg]

I've heard that the only difference is 8 pounds, because the bigger one is made out of a material that isn't as stiff. That might just have been comparing X bar to Y bar rather then ALL 1" bars to 1 1/8" bars. :crazy:

 

[roadracer]

If the bar is made of steel, Youngs Modulus is constant regardless of the "strength" of the material.

The only way to effect stiffness is to change the geometry (ie: diameter of the bar, length of end links etc...)

... or change to a different material (aluminum, brass, copper etc...)

 

[mitzel]

I looked up an early 80's Mustang Monthly article "How to Improve Your
Mustang's Handling". The article used a 5/8" front sway bar as a baseline
and reported a 1" bar is 226% as stiff and 1-1/8" is 244%. My math skills
may be a bit rusty but I think that comes out to 1-1/8" being ~8% stiffer
than 1".

The article also preaches balancing ratio of front to rear torsional
stiffness. The base of 5/8" front sway bar and no rear sway bar is
reported as ratio of 3.12 front to rear, and it's fairly well known
this stock setup induces plenty of understeer. Stiffening just the
front with 1" raises the ratio to 5, and 1-1/8" raises it to 5.62.
The article suggests a ratio of ~1.4 to 1.5 for small block Mustang,
which requires 5/8" or 11/16" rear bar with 1" front, and 11/16" or
3/4" rear with 1-1/8" front. I'm sure aftermarket front & rear springs,
A-arm relocate, car weight, etc. all have different effects but I just
thought the general info was interesting.


danny

 

[Hottarod]

Even with a 1 inch I had to notch my frame rail. Which ever one you get needs to be matched with the right diameter rear one.

 

[Huskinhano]

You haven't given any info on your present specs or your intended use. Personally, maybe because I'm getting to be an old fart, I'd rather have a slightly soft suspension for the street. The street is not a race track, it has potholes, bumps and what not. I'd rather have a suspension that can react to these imperfections and keep the wheels in contact with the road, not in the air! I'd rather see improvements in geometry, such as lowering your upper control arm and some unibdy stiffening such as sub frame connectors and Monte' Carlo bar. Also I'd highly recomend getting and reading a good suspension book.

I often wondered with stiff springs, shocks and big bar just how much the unibody is flexing before the suspension moves?

 

[slim]

Charley, I agree, if looked at strictly as a torsion bar the twist torque is proportional to diameter to the fourth (the polar moment of inertia). This would indicate 60% increase for 1- 1/8"compared to 1". In reality non torsional deflection, the bends, links and bushings all reduce this theoretical increase. That's why my guess was only a 25% increase.