Never an issue in my 85.

JamesC

 

There may be a simple explanation for this. They may not list it or the factory part may not be the same as the replacement part. It is highly likely that these parts were on the cars, but when they were exhausted they simply went to a suitable replacement. They do this all the time in my industry... This is what I have seen...

"Superseded" parts are those that have been changed (given a new part number) and the old one is no longer made.
"Optional Supersedure" Where they have two parts and they can be interchanged, The difference may be as simple as a different manufacturer, or they differences in them is so minor that they can be interchanged.
"Cancelled" Obviously parts that are no longer available
"Spares" Usually these parts are not exactly the same as the OE part originally installed at the factory, They could require modification or are simply slightly different than the original part.

They may not spell it out this way on the books, but typically that is what I have seen...

It would probably explain why the 25mm is no longer available...

 

I realize you're just tracking sway bars, but keep in mind the suspensions worked as a system and the different sized bars also came with different rate springs. I upgraded my 1985 F41 suspension (30/19) with WS6 bars (36/24) and am replacing the factory springs with Hotchkis.

 

Actually, Since you are going with the Hotchkis springs, you might want to go with their entire system... Like you mentioned when they installed the larger sway bars, they also installed different spring weights. Also Keep in mind that Camaros and Firebirds were different, Firebirds have a softer ride than Camaros but they handle the same... Its bizarre, but that is from articles back in the day that said the Camaro would beat you to death, where the Trans Am had a much better ride in comparison.

I know the WS6 sway bars were hollow, to save weight, The Solid 34mm on the camaro with the "wonderbar" performed the same as the hollow 36mm sway bars, and I think the 36mm was still lighter overall, especially if you add in the weight of the wonderbar...

One thing I have learned is the more I messed with my suspension, sure it handles like its on rails, but the less I enjoy the car... I am actually going to eventually go away from the KYB adjustable shocks & struts for old-school gas filled... Getting old and hard ride is not enjoyable any more...

 

I also have a 25mm rear bar, however not positive which car it came off, I think a 85, but could have been 86

 

Unless it was installed by a previous owner - It was from an 85.

 

Well, I upgraded to the WS6 bars over 15 years ago, so since I already have them I'll stick with them. I got the idea from a Hot Rod magazine buildup in the early 90's, before Hotchkis started making sway bars for the Thirdgens. However I agree mixing unmatched components can lead to unexpected results. Why re-do the work someone already paid their engineering staff to perform and test?

 

The profundity of statement cannot be overemphasized. Not just for sway bars, but for almost every system on a car.

Sure, new cars are engineered to the average consumer's taste and to a price so there will be compromises. But I have found that by and large, OE designs work quite well. Piecing together a suspesion or and engine only works if you know what you are doing.

Since I fall into the "don't know what I am doing" category, I have found that minor, balanced modifications yield the best results. In my younger days, I fell into several "bigger is better" mistakes.

 

I have an 85 ta with a 25mm rear bar, it also has a 34mm front bar. As far as I can tell they are stock on the car. And I also have the lg4

 

That front bar on your 85 should be a SOLID 34mm, unlike the hollow 34mm bar used on 86+ cars.

 

I know about the solid bars, and figured that I had the solid 34mm up front.

I was trying to help out with the 25mm rear bars and show a car that is currently running and has that bar on it.

There's a few pictures of it on here being measured with a caliper.
http://i1294.photobucket.com/albums/...ps84775511.jpg

http://i1294.photobucket.com/albums/...ps5c9f300a.jpg

And here is my front not a very good picture but just to show.

http://i1294.photobucket.com/albums/...psd39471d2.jpg

 

They were different, but I wonder if Firebirds just felt softer rather than actually were, maybe it was the better seats. I know for a fact (I used to have GM spring codes and what came with what as well as sway bars... I wish I knew where they were now), for the most part they were available with the same springs and sway bars on the front (GM changed them as they went down the production line to match how the car was optioned), but a comparable trim level 'bird would get stiffer springs and/or bars on the back. Pontiac was GM's performance division and chevy was it's economy, and a stiffer rear suspension will typically push the car more neutral or more aggressive ("fast" at the track). Another possibility would be different shock valving

Honestly, looking at these lists I'm fairly certain that they're incomplete or inaccurate. It would be one thing if later years didn't show bars that came on earlier cars and there were later cars that came with them (at least at that point we'd know that they were made before and may have been substituted), but for example, my '83 TA (an LU5/WS6 car) came with a 32mm front and 24mm rear (and I'm almost positive it was factory equipped that way, never replaced), and none of the lists show a 24mm till '85 (except for the '84 "special").

I also find it funny how everyone seems to think that the 34mm hollow front is dead common but I've never seen one or been able to find one except on a friend's TTA (I've looked for them and tried to buy one a few times, 2x I got a 36 mailed to me)

 

One thing we still have to keep in mind that the original equipment probably is not the same as the replacement parts. I suspect the Parts catalog does not list every possible spring available at the time of assembly, but rather they have some generics that work within a range for replacement.

 

I have a 1989 IROC Z and I can t believe that with the 16 in tires that are 50 s they wouldn't put the 36mm in front.

 

I have a 1989 IROC Z and I can t believe that with the 16 in tires that are 50 s they wouldn't put the 36mm in front.