ladder bar front adjustments

[racer78mc]

well, i have a very strange set up. i have a ladder bar set up on a 1978 monte carlo and it has stock shocks and stock coil springs. the front setting on the ladder bars is in the bottom hole, it doesnt have much travel to it when lauching from the starting line. but it does pick up the tires and tote them a few feet out. could some one tell me, if it would help or hurt anything if i move the bars up a few holes. if more info is needed , please just let me know.....

[want-a-be]

I'd give it a try. How high does it hike the front wheels?

Don

[racer78mc]

well, it'll pick em up about 6 inches and carry them out about 5 or 6 feet....i guess what i'm asking would it hit the tires harder if i put the bars in the top hole at the cross bar. right now its at the bottom hole. i have 5 holes in my cross bar and i do have the pinion angle set and the preload,really just wondering if i change this setting, and go up with the bars, does it hit harder......thanks

[want-a-be]

I would think so.

Don

[70NOVA]

The Bars Should Be As Close To Level As Poss.
Up = Harder Hit But Less Down Track

[projim64]

The Bars Should Be As Close To Level As Poss.
Up = Harder Hit But Less Down Track

What do you mean by less down track ? I am helping a friend with a 65 Comet N/SS that is heavily weight biased to the front 58% front to 42% rear. Right know we have the ladder bars up from level in the front about 3 inches to try and help hit the tires harder to compensate for the front end weight .Are we thinking right by doing this or is there a better way ? Should we be looking at adding weight to the rear say a steel bumper instead of the fiberglass one we have ? Thanks for any help , Jim.

[70NOVA]

less down force down track on mine i added weight to rear and went up on front of bars and it hooked to hard so i went back to center and hooked nice and carried wheels nice on a soft leave

[projim64]

Thanks for the reply . The 65 Comet I am helping with is hooking good but is getting a little loose down trck and bouncing around a bit. Here is one of the latest runs any advise . Thanks ,Jim
http://www.hubgarage.com/mygarage/Tunne ... ideos/7654

[dadnova]

OK, help me understand the less down track theory??
If the bars are raised it lifts the rear end of the car causing a seperation in the suspention and therefore pushing the tires down into the pavement.

If the car is still pushing down track, wouldn't the force from the raised position still be seperating the suspention causing the tires to go down??

[sunsation540]

[quote="dadnova"]OK, help me understand the less down track theory??
If the bars are raised it lifts the rear end of the car causing a seperation in the suspention and therefore pushing the tires down into the pavement.

If the car is still pushing down track, wouldn't the force from the raised position still be seperating the suspention causing the tires to go down??[/quote] and changing the center of gravity and moving weight forward

[ky mustang]

The suspension is trying to separate always no matter what angle the bars are set at.

The squatting and anti squatting action you see between the tire and body is a product of how much weight is transferred from the force of gravity trying to hold the car in place and the power (force) of your engine pushing against it.

Where your ic is located , power level , and where the cog of the chassis is at is what distributes this weight and provides traction.

The force comes from your tire patch and extends in a straight line through your ic and on through the entire car.

There is a certain amount of weight on top of this line and a certain amount below this line, what dictates if the setting works is if the weight is balanced to your power level and provides enough traction.

With traction the weight (force) will transfer through an angled inertia effect and tend to compress the suspension if there is more weight on top of this line , if there is more weight on the bottom of this line the suspension will be allowed to separate because there is not enough weight (force) to stop it from doing so.

The trick is to balance this so there is very little or no separation or compression of suspension , plenty of traction to keep it hooked , and no monster wheel stand.

Billy Shope was very instrumental in helping me see this , I have seen a lot of people disagree with his theories , but I believe he is right on in most cases.

If you think about it every car has to have its own neutral line and cog its going to be different in every car. The power level is all that changes if the car is balanced correctly at its current state. The engine is either too high , too far back , etc. The more power you have the more forward and low the weight has to be.

[dadnova]

Just read a very good artical by Billy Slope. Makes alot of sence. I have to find a starting point again and start over, vidio will help on whice way to go from where I start.
We re-sub framed the car and frame and added a new engine combo so we have to start all over. First few trips out we got no traction at launch and when the Turbo kicked in lost what traction we had down track. Best pass with the new combo in 1/8 was 1.8 60' foot 7. sec et. @ 111mph slipping and sliding all the way down the track.
Should probably four corner weight it first.

A good problem to have in one sence, but alot of suspention tuning needed to hook up like we used too.

[BillyShope]

The "bars" of a ladder bar suspension shouldn't be confused with the "links" of a 4 link. A "link" has pivots at BOTH ends. The "bar" of a ladder bar car is merely an extension of the axle housing and, as such, its angle relative to the ground is of no concern. The important matter is the location of the front pivot, which is the "instant center" of the ladder bar car. The higher the hole used, the greater the percent antisquat.

If you have a ladder bar car, you could say that you have a "zero-link" suspension (not counting the Panhard link, of course). The same would be true if you have an old Ford or Chevrolet with a torque tube suspension.

Unless parts are falling off your car as you go down the strip, the location of the center of gravity remains fixed. The weight transfer, however, varies with the acceleration.
http://www.racetec.cc/shope

[rustbucket]

not trying to hijack the thread, but quick question while we're on the topic. does a anti-roll do anything for a ladder bar car? thanks

[BillyShope]

not trying to hijack the thread, but quick question while we're on the topic. does a anti-roll do anything for a ladder bar car? thanks

Very good question! There are those who say that an ARB is not needed on a ladder car. But, there are others who say that they've added the ARB and have improved their sixties.

Certainly, if there was absolutely no deflection with the ladder bar car, there would be no need for an ARB. But, that's not a reasonable assumption. There will always be some deflection, which means that the added stiffness resulting from the addition of an ARB will increase the rear roll stiffness even further and thereby help to keep the rear tire loading equal.

So, the answer comes down to: Is the improvement measurable? Those with the improved timing slips say that it is, while others still insist that it isn't.

I look at it this way: It's like a football team trying to score with plays that take the ball halfway to the goal line. There will always be some roll stiffness at the front suspension, so you can never reach your goal by simply increasing rear roll stiffness.

A better solution...with a ladder bar car...is to use a higher rate spring at the right front than at the left front. This will require adjustable coilovers so that you can equalize rear tire loading on the scales. With the proper spring rates, you can have equal rear tire loading for any value of driveshaft torque. There's a spreadsheet at my site which covers this.
http://www.racetec.cc/shope