Ladder bar suspension setup

Currently at level with the ground on the ladder bar, in the middle hole, with neg 2 degrees pinion angle.

Shocks on 3 clicks from full soft on both extention and compression. Advice and ideas?? Thanks, Arnie. The great popularity of the anti-roll bar is because of its effect on launch loads of the rear tires. I get the impression that many who use the anti-roll bar do not understand how it's helping them. The visible effect It accomplishes this because, with its use, rear roll stiffness is increased relative to front roll stiffness.

But, since the front roll stiffness can never be entirely eliminated, an anti-roll bar is not the total answer.

You don't mention individual static tire loads. I'll assume that Understand, however, that, upon launch, the driveshaft torque causes them to be anything but equal.

In other words, the nice symmetry, that you have statically, no longer exists during launch. So, in order to equalize rear tire loading on launch, you have to build some asymmetry into your setup. There are many ways to add the necessary asymmetry. At my site, for instance, I have a spreadsheet on one of the pages which describes an asymmetric adjustment of a ladder bar car.

This suggestion alarms some who fear a safety and driveability problem. What must be understood is that the asymmetry can solve the loading problem statically or dynamically. For instance, a static solution would be to simply increase the right rear loading and decrease the left rear until, on launch, loading is equalized.

Unfortunately, this would mean that I don't think not being able to do wheelstands is going to be a problem, maybe just the opposite. Last edited: Jan 8, Larry T , Jan 8, Joined: Mar 6, Posts: 11, Profile Page.

Hoping to improve my tech question record of late, anyway , just wondering The reason I ask is that I find the automotive math here fascinating - calculating the lengths of the bars for racing - but I've never heard it discussed once with regards to building a street car using SOCAL's long style bars that are very popular.

Is it just that unimportant on a street car? Here's a 42 Chevy PU I'm doing for a friend. I need to add a panhard bar. Trailing arms are similar to the old Chevy c10 rear suspension. I had to step up the rear chassis to make it work. Joined: Jul 6, Posts: 2, Profile Page. I had Sid of www. I have gathered all the parts and hope to start this spring, when other projects leave the shop! Will post pics then. Last edited: Jan 9, Joined: Sep 28, Posts: 2, Profile Page.

Dueced - If you want full use of the action of your bars If you have stiff shocks Might be a good idea to go look into Jerry Bickels suspension book before you go too far. It's very informative reading. While mostly race stuff, it can be used on the street with some thought. Mike VV , Jan 9, Joined: Feb 21, Posts: 4, Profile Page. Check the websites of the chassis companies, I remember them having good diagrams for geometry to help people order 4 links and ladderbars.

Been a while since I've needed them so I can't make a recommendation. Not sure about that, maybe someone else can chime in. On paper you would think so however it seems most of the truck arm are angled in from the outer axle area to the center area of the chassis.

Not sure if that or the mounting style affects the math. Well here is one of them. Pinion angle is measured in reference to the angle of the pinion gear compared to the driveshaft. As I said, to the driveshaft—not to the ground, transmission, engine, or any of the many other methods I have heard of. Those measurements are important for other reasons, but they have nothing to do with pinion angle. Before you go out and add to the pinion angle under your car, know that pinion angle robs horsepower as the engine overcomes the pinion angle.

This happens no matter how much pinion angle is installed into the car. The more pinion angle there is, the more horsepower is needed or robbed from the engine , which could be otherwise used to accelerate the car faster. This leverage effect uses the weight of the car to drive the tires harder into the pavement. Pinion angle represents the difference between the driveshaft and the pinion gear, nothing else.

How much you choose to run can aid in tuning how your car launches. The proper technique for checking driveshaft angle is to have the vehicle at rest on a level surface with the weight on the tires. A drive on lift is optimal. Place the angle finder on the driveshaft as shown and read the gauge. Accuracy is key. Just be sure to double-check your measurements and use good-quality tools. You need to unbolt the driveshaft and use the pinion yoke to get an accurate measurement.

Again, the car has to be at rest on a level surface with the weight on the tires. This is the digital angle finder manufactured by Allstar. Always run the least amount of pinion angle necessary to get your car to hook, but not so much as to waste horsepower.

I suggest a starting point of 2 degrees negative pinion angle for cars in the hp range, and maybe 4 degrees for cars in the hp range. When you measure your driveshaft angle e. A reasonable amount of fuel should be in the tank typically half-full.

The car must be setting on all four tires inflated to race pressure. In most factory production cars, to get longevity of parts, I have seen a positive number to near zero degrees pinion angle depending upon the age of the chassis components being used, especially the springs. To change the pinion angle, wedges can be installed between the spring mounts and the leaf springs, thus tipping the pinion either upward or downward depending upon the shim being used and its direction.

Preload and spring wrap-up can be controlled using traction bars or slapper bars, which are the most common methods used in lower-horsepower cars. A slapper bar gets its name because it bolts to the existing spring U-bolts, replacing the plate under the spring and extending forward.

There are many different versions of these types of traction bars for leaf springs. A gap is left between the snubber on the front end of the traction bar and the spring. The gap can be different on either side before slapping the frame or the front of the spring depending upon the style in use , thus creating preload.

Moving the driver-side traction bar snubber closer to the frame creates preload, helping to keep the car from turning right. If you need more preload, adjust either the passenger-side snubber first choice closer to the frame or back the driver-side snubber second choice away from the frame. If your car turns right upon launch, you need more preload and should adjust the passenger-side snubber closer to the frame.

If your car turns left upon launch, then you need less preload and should adjust the passenger-side snubber farther away from the frame. Remember, the more distance the snubber is from the frame or spring the longer it takes before the car reacts to your settings. For those of you running rear-wheel-drive GM cars with leaf springs, Landrum Spring Company makes what they refer to as a Parabolic leaf spring. The Parabolic spring is a mono-leaf design that is thicker in the middle and tapers as it moves closer to the ends of the spring.

This thinner leaf at the end allows the car to plant the rear tires quicker and harder. The thicker middle part of the spring helps prevent spring wrap-up. You still need some sort of slapper bar or a set of CalTracs traction bars to stiffen up the front half of the spring.

These leaf spring wedges are used to adjust pinion angle on vehicles equipped with rear leaf springs. The wedge is mounted between the spring mount pad and the leaf spring itself. Doing so changes the angle the axle housing sits at. These bolt-on slapper bars from Competition Engineering are typical and affordable. They are easy to install and can be used to adjust suspension preload while stiffening the front half of the spring.

This is my former Olds Omega drag car. This is Dan Zrust in a Plymouth Barracuda. The car competes in the notoriously tough Super Stock ranks and is powered by the venerable ci Chrysler Hemi engine. Nationals in Indianapolis, Indiana. Chrysler muscle cars have the option of Mopar super stock springs. They have a heavier spring rate on the passenger side than on the driver side, thus creating preload.

Additionally, they are much stiffer in the front half of the spring due to the axle not being centered on the spring than the rear half, creating a rear suspension that works like a ladder bar setup. I always liked to see the Chrysler Super Stock cars leave the starting line. You could tell how good they were, planting the rear tires, by the amount of separation visible between the leaves in the back half of the springs.

Eventually, spring clamps were used to eliminate this separation and to create even better foot times, as the lesser amounts of separation caused the tire to be pushed into the pavement quicker.

The Mopar super stock spring name came from the fact they were developed in the late s by Chrysler for its NHRA Super Stock race cars to give them maximum traction with minimum research and an advantage over the GM and Ford Super Stock cars of the time. Some of the more notable Chrysler Super Stock racers were the Mancini brothers, who produced a string of successful Chrysler factory-backed race cars.

Mancini Racing used that race experience to grow into a parts business that sells suspension parts for Chrysler race cars. Whether you are using Chry-ler super stock springs or not, the ride height can be controlled by re-arching the existing leaf springs. Most large cities still have businesses that re-arch springs for truck or trailer applications, and should be able to do your car springs.

Should the rear suspension rise or squat upon launch? The location of the front mount height in the chassis of the rear-end leaf spring deter-mines whether the car lifts in the rear or squats in the rear when leaving the starting line. If the mount is above the neutral line, the chassis lifts in the rear. If the mount is below the neutral line, the chassis squats in the rear.

I have tried to drive the point home that a car which lifts in the rear will plant the rear tires harder. This is true to a point. You first must understand the basics. However, there is a point in horse-power-to-weight ratio that some cars with higher horsepower levels to 1, need the front of the leaf spring mount to be lowered.

Thirty years ago most full-bodied cars benefitted from a higher front leaf spring mount. Using the drawing on page 18 the fact of whether the car lifts or squats in the rear depends upon where the front spring mount is in relation to the neutral line. Lower-horsepower cars can use a higher mount thus making the car lift in the rear upon launch. As horse-power levels to 1, increase, the mount needs to be lowered. The reason for the necessary lower mount is high-speed stability.

A car lifting in the rear plants the tires harder but with that same lift at the top end it loses traction. Now as the horse-power gets higher and higher more than 1, the car hasthe ability to break the tires loose on the top end.

For safety and to be able to complete the run the front spring mount needs to be lowered. However the opposite occurs at the starting line. Most 1,plus-hp cars today have some sort of power adder NOS, blower, supercharger and can adjust the starting line power to compensate.

There is no exact measurement.