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How do I properly measure the diameter of a sway bar?

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Old 08-16-2012, 06:48 PM
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Default How do I properly measure the diameter of a sway bar?

I have been talking through some plans with New Era via e-mail, and the representative asked me "2.) What size sway bars do you have? I need to know diameter of front and rear."

I brought a tape measure out this afternoon and realized I am unsure how to properly measure the sway bars...do I measure from stabilizer clamp to clamp, run a measuring tape along the bent bar, or something totally different?

If anyone happens to know stock measurements of front/rear sway bar it's a 1998 SS.

I also attached a pic of the rear shock, does that look stock?

Thanks!
Attached Thumbnails How do I properly measure the diameter of a sway bar?-img_1118.jpg  
Old 08-16-2012, 07:17 PM
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Take an adjustable (crescent) wrench and snug it up on the bar, and measure the gap. Shock looks stock and I think the bars are 30mm front and 19mm rear. Search the suspension section all the measurements are there.

sway bar link https://ls1tech.com/forums/suspensio...bar-sizes.html

Last edited by Carter Hays; 08-16-2012 at 07:26 PM. Reason: sway size
Old 08-16-2012, 07:31 PM
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Thank you!
Old 08-16-2012, 07:40 PM
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The diameter is 1/2 of the circumference.
Old 08-17-2012, 04:11 AM
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you forgot about PI, the formula for circumference is C = PI times D.

To find the sway bar thickness (diameter) you take C and divide that by PI(3.14) to find D.

String near the endlinks will get your calculation pretty close
Old 08-17-2012, 08:10 AM
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The crescent wrench is a good idea, or take a piece of string and wrap it around the bar marking where they overlap. Then take a tape measure and measure the length of string. Then divide that number by 3.14 and you have your diameter. It will most likely be in inches unless you have a metric tape measure. If it's in inches multiply how ever many inches by 25.4 to get mm.

And yes, those are stock decarbon shocks (they suck)
Old 08-17-2012, 06:59 PM
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I appreciate all the input everyone, I'm going to head to autozone tomorrow and pick up a metric tape measure then knock this out. Metric tape measure doesn't sound like a bad thing to have laying around.
Old 08-18-2012, 11:45 AM
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Originally Posted by cdgreg
I have been talking through some plans with New Era via e-mail, and the representative asked me "2.) What size sway bars do you have? I need to know diameter of front and rear."

I brought a tape measure out this afternoon and realized I am unsure how to properly measure the sway bars...do I measure from stabilizer clamp to clamp, run a measuring tape along the bent bar, or something totally different?

If anyone happens to know stock measurements of front/rear sway bar it's a 1998 SS.

I also attached a pic of the rear shock, does that look stock?

Thanks!
Stock SS sizes are 32mm front, 19mm rear.
And yes, those are the stock Decarbon shocks (fine for drag, terrible for anything else).
What exactly are you looking to do with the car?
Old 08-18-2012, 01:58 PM
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Originally Posted by JD_AMG
Stock SS sizes are 32mm front, 19mm rear.
And yes, those are the stock Decarbon shocks (fine for drag, terrible for anything else).
What exactly are you looking to do with the car?
Hah, damn that's impressive. I literally just got home from harbor freight buying a $3 utility caliper and measured the sway bars to be 18-20ish on the back, and 31-32ish in the front which means your 32/19 is perfect lol.

As for the car, one of my life aspirations is really to learn how to drive, and tackle some real tracks. Now, in terms of this car, which is a convertible, A4 with 140k+ miles on it, the goal is to be an occasional weekend auto cross warrior not worrying about being competitive or class standards, but more just to have a fun time and start to learn. The NewEra rep recommended a good set of tires, new bushings, and asked about the size of the sway bars.

From reading the "favorite mod" thread on this forum, I am going to also inquire about welded in sub frame connectors. Beyond that, I'm looking at the standard LT headers, catted-exhaust and a stall convertor. I would like to keep the ride pleasant for the 95% of the time my wife and I are cruising in it, so I'm not sure if shock replacement would be wise? As much as I would love to plan on heads/intake/cam the realization that the engine has 142k miles on it scares me...
Old 08-18-2012, 04:59 PM
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Originally Posted by cdgreg
Hah, damn that's impressive. I literally just got home from harbor freight buying a $3 utility caliper and measured the sway bars to be 18-20ish on the back, and 31-32ish in the front which means your 32/19 is perfect lol.
As for the car, one of my life aspirations is really to learn how to drive, and tackle some real tracks. Now, in terms of this car, which is a convertible, A4 with 140k+ miles on it, the goal is to be an occasional weekend auto cross warrior not worrying about being competitive or class standards, but more just to have a fun time and start to learn. The NewEra rep recommended a good set of tires, new bushings, and asked about the size of the sway bars.

From reading the "favorite mod" thread on this forum, I am going to also inquire about welded in sub frame connectors. Beyond that, I'm looking at the standard LT headers, catted-exhaust and a stall convertor. I would like to keep the ride pleasant for the 95% of the time my wife and I are cruising in it, so I'm not sure if shock replacement would be wise? As much as I would love to plan on heads/intake/cam the realization that the engine has 142k miles on it scares me...
Shock replacement should be #1 on the list, and will make the most difference out of anything you will do (assuming nothing is broken/royally screw up). Tires will also obviously make a massive difference, but with shocks that can completely change the way the car drives, feels, behaves, is balanced, and how quickly things happen (how quickly the car steps out on your for example). My recommendation would be Koni SAs (http://www.stranoparts.com/partdetai...D=20&ModelID=7) - massive difference in overall handling (all the above things I said) and adjustable rebound so you can dial them in to your liking and these will ride far better than the stock decarbons (think BMW-like). These were used by Sam Strano to win multiple national autox champions. I have them (amongst many other mods) and they are certainly my favorite mod by far, and made the most difference out of everything.
Bushings-wise stick with stock or 1LE rubber replacements (http://www.stranoparts.com/partdetai...D=18&ModelID=7). Poly will bind and cause a harsh ride and unpredictable handling (and in some cases broken control arms from the bind). Rod end will be best for handling but make noise and may ride harsher at times (although offers full suspension articulation unlike poly).
Your stock swaybars are well balanced, but if you choose to upgrade go with 35mm front, 21 or 22mm rear (no bigger, many companies try to sell 25mm+ bars as handling bars when really they are not). This is a proven very balanced setup.
Old 08-18-2012, 06:24 PM
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Thanks! I'm new to all of this, but the Koni SA recommendation definitely aligns with what I have scoured over on the forums. Would you recommend replacing the stock springs or will that really kill the ride quality (I'm all for a BMW type ride quality)? Assuming you recommend changing the springs as well, should the order be shocks> sub frame connectors> springs? Sadly I doubt I'll be able to afford it all in one foul swoop.
Old 08-19-2012, 08:37 AM
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Originally Posted by cdgreg
Thanks! I'm new to all of this, but the Koni SA recommendation definitely aligns with what I have scoured over on the forums. Would you recommend replacing the stock springs or will that really kill the ride quality (I'm all for a BMW type ride quality)? Assuming you recommend changing the springs as well, should the order be shocks> sub frame connectors> springs? Sadly I doubt I'll be able to afford it all in one foul swoop.
If you are unhappy with your stance, or want a further improvement in cornering then go for [proper] lowering springs (like strano springs). But all lowering springs will ride stiffer/harsher then the stock springs (as you loose suspension travel and gain spring rate), this is just the trade off.
Also IMO dont do anything all at once either way. By doing things one at a time you get to see what part changes what about the car and you can adjust/decide what you want to do from there. You may add something you end up not liking, but wont know what part it is if you threw everything on there at once.
Old 08-23-2012, 02:19 PM
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On the subject of shocks - for stock ride height I LOVE my Bilstiens. A little firm but NOT harsh. Handles very well and even takes train tracks with stride. Oh, and rest of the car (bushings, springs, bars, etc) has 135k miles on it. NOBODY believes I have that kinda miles until they see the odometer it rides so nice. AND it has worn out Kuhmo ASXs on it.



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