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Title:Sway Bar Information

Author:Geoff Moore (betterthanyou)

Chevrolet S-Series Stabilizer Bar How To

Stabilizer bars (or anti-roll bars) stiffness increases with the 4th power of the radius, a 20mm bar is 52% stiffer than an 18mm bar. Stiffness is directly proportional to the length of the end arm where it is attached to the lower control arm. Adjustment at the end of the arm, allows tuning of the stiffness slightly, but not much adjustment can be done on a stock production components. The alloy of the steel, that the bar is made of, does not make much difference in the stiffness - as the Sheer Modulus of Elasticity does not vary much between different types of steel alloys.
Adjusting the stabilizer bars is a good way to tune the car's cornering response, as they act like springs, but only when the wheels are moving relative to each one another. The stabilizer bar has no effect when hitting a bump with both wheels at once. This enhances ride comfort, as many road surface irregularities are hit by both wheels at once. During cornering, the suspension on the outside of the turn compresses while the inside suspension expands, here the stabilizer bar comes into effect by providing additional spring rate under cornering, reducing body roll and improving traction.
Stiffening the stabilizer bar at one end will improve weight transfer to the other end, resulting in improved traction on the opposite end of the stabilizer bar. The rear stabilizer bar should be stiffened to reduce to under steer. Using a significantly larger rear stabilizer bar will eliminate the under steer, but the bars must be proportional to the spring rate, so too large of a rear bar will not work well with stock springs, and in fact it might cause the inside rear tire to lift of the ground in a corner.
Using a slightly stiffer stabilizer bar in front will help control body roll, depending on the front springs, and using a significantly larger rear stabilizer bar will eliminate the under steer. Stiffening the front bar will improve weight transfer in the rear, getting more traction back there, but will also reduce front body roll and keep the tires more upright and will improve front traction as well.

The Chevrolet S-series was available with several different stabilizer bar sizes and types. During the first generation of trucks, only front stabilizer bars were available. 4x2 and 4x4 models used different sizes and mounting systems. They are NOT cross compatible. Blazers and Jimmy's use a different rear stabilizer bar than the pickup trucks. They are also NOT cross compatible. In the 1995 model year, the rear stabilizer bar was introduced to the S-Series line of trucks. Below you will find a table of stabilizer bar sizes for the front and rear of both the Blazer/Jimmy and pickup models.

2X4 Front All years	4x4 Front 1982-1994	4X4 Front 1995-2003
2X4 Rear 1995+ (ZQ8 only)	4X4 Rear 1995+ (2Dr Blazer/Jimmy Only)	4x4 Rear 1995+ (4Dr Blazer/Jimmy Only)

So what can we do with all this information? Well to state the obvious we can MODIFY! For example all 2X4 pickup trucks and Blazer/Jimmy's used the same stabilizer bar setup. So if we were to source a nice 33mm stabilizer bar and go out and buy the correct bushings you could upgrade a truck with the smallest or no front stabilizer bar to the largest with just a couple hours work and largely increase the roll characteristics. Or how about adding a rear stabilizer bar to a first or second generation generation 2X4 pickup? Well there is a large source of aftermarket rear stabilizer bars available for first and second generation trucks. These bars clamp to the rear axle and end links are placed through holes already in the frame. These bars work incredibly well and require little work. However there is an up front cost involved.

Here you can see a Belltech rear stabilizer bar installed on a first generation pickup.

Here is an image of the aftermarket stabilizer bar ends secured to the frame rail via the provided end links. These end links are similar to the ones found on the front suspension.

However, as luck would have it the second generation trucks with the ZQ8 suspension package came stock with a rear stabilizer bar. If you can find one of these trucks in a salvage yard you can remove the bar and its components and install them on any 4X2 pickup truck. This method does require drilling or welding the stabilizer bar linkage brackets onto the stock shock mounts. If you are interested in this type of installation here is a complete list of parts you will need. GM part numbers are included incase you need to buy some new ones.

Link Bracket #15989672-Qty.-1

 

Here is a ZQ8 rear stabilizer bar installed on a pickup truck not originally equipped with a rear stabilizer bar.

Ok so what about a 4X4 truck? Well the 4X4 pickups and Blazer/Jimmy's used 2 styles of front bar. They are cross compatible between pickups and Blazer/Jimmy's so long as the year range is the same (see the above tables and illustrations) you can install a bar from a donor truck. Don't forget to get the correct bushings and it will be a straight bolt in.

Now 4X4 Pickups were never available with a rear bar. But you can use the same ZQ8 bar as mentioned above for all years of pickup and install it provided you have all the brackets. Blazer/Jimmy's were divided in the rear by either a 2 door or 4 door model. However, only second generation trucks have the required brackets installed on the frame. On Blazer/Jimmy's the brackets are welded on or are an actual part of the frame work. Because of this it would be best to source an aftermarket bar for first generation trucks that mounts differently. On second generation Blazer/Jimmy's without a bar or with a small bar, you can install or upgrade your bar as long and you find a corresponding 2 door or 4 door donor truck.

With all this information you should be able to come up with you own stabilizer bar combinations to suit any of your needs. Enjoy!

Written by: Geoff Moore (betterthanyou)

Information Provided By : stretch59, Triaged, cryptk, Dougofthenorth, SmallBlock, Falconxl, BAJAChic, sierra, Jimmy90, 85 long box