Ladder bar leaf spring guys

[b.guggenmos]

Originally Posted by Mike Pearson

Just don't move the bars past level with the bottom of the rocker panel. Mine has a down angle of 1-2 degrees. Horsepower and good chassis is what will make the car get up in the front. Moving the bar down will make it hit the tire harder.

I have been racing a ladder bar leaf spring car for a very long time and admit I struggle with them. I bought Tim Morgans Doorslammers The Chassis book many years ago and have always thought moving the bars up hits the tire harder not down as stated in the book? So I just did a search and talk about information overload! Total opposite diagrams from different vendors for hits tire harder by raising or lowering the front of the bar. No wonder people are confused. I am! I don't post here often but read a lot. Thanks and hopefully some of this will help the person that started the thread.

[joespanova]

Originally Posted by b.guggenmos

I have been racing a ladder bar leaf spring car for a very long time and admit I struggle with them. I bought Tim Morgans Doorslammers The Chassis book many years ago and have always thought moving the bars up hits the tire harder not down as stated in the book? So I just did a search and talk about information overload! Total opposite diagrams from different vendors for hits tire harder by raising or lowering the front of the bar. No wonder people are confused. I am! I don't post here often but read a lot. Thanks and hopefully some of this will help the person that started the thread.

I've SEEN THE SAME THING. Apparently the theory for 4 links and ladder bars is not quite the same.
Trial and error............

[nhramnl]

[QUOTE=b.guggenmos;546274]Not necessarily. That depends on where he is at now? Raising the bar moves the instant center rearward and higher and hits the tire harder. That may or may not make it try to wheel stand more?

This is good information. The higher into the chassis the front of the bar goes, the more tire hit, because you're getting less "leverage" against the chassis. The result of that loss of leverage is that the tire is driven into the track harder. The other side of the equation is that when the front attaching point of the bar is lowered, the car still may not wheelstand a great deal, because it simply may not have enough power to "lift" the chassis.

[Mike Pearson]

Originally Posted by joespanova

I have had the car VERY wheel stand prone in the past..........to the point of damaging stuff.
Since I lowered the ride height in the rear it wont..........so to recover ( some ) I either move the bars or lower the housing on the perches.....I dont want to raise the azz end up a hole on the perches , sooo.........past level?
I'm already slightly down a degree or so............so I either go down more or up 1 hole as has been suggested.
The consequence of breaking parallel , at least from going DOWN some is already noted. The result of going UP is not.

I can tell you from experience with my car that if the bottom of the ladder bar is running on an upward angle in comparison to the frame of the car it will not hook the tires. A slight downward angle has always been better on my car. 3150 Lbs. and it will 60 ft in the 1.28 - 1.29 range when the air is good. This is with a PG.

[joespanova]

Originally Posted by Mike Pearson

I can tell you from experience with my car that if the bottom of the ladder bar is running on an upward angle in comparison to the frame of the car it will not hook the tires. A slight downward angle has always been better on my car. 3150 Lbs. and it will 60 ft in the 1.28 - 1.29 range when the air is good. This is with a PG.

I'm NOT DOUBTING YOU.....I'm just sayin'.

[Tom Broome]

Originally Posted by joespanova

I have had the car VERY wheel stand prone in the past..........to the point of damaging stuff.
Since I lowered the ride height in the rear it wont..........so to recover ( some ) I either move the bars or lower the housing on the perches.....I dont want to raise the azz end up a hole on the perches , sooo.........past level?
I'm already slightly down a degree or so............so I either go down more or up 1 hole as has been suggested.
The consequence of breaking parallel , at least from going DOWN some is already noted. The result of going UP is not.

I'll try to keep this short.
You lowered your car and it doesn't wheelstand as much. When the center of gravity is lower in relation to the rear axle the car will not transfer weight as easily.
Did you lower the front at the same time?
I expect the solution can be found in the front suspension. How much travel? How much stored energy? What is your front spring rate?

I'm assuming your car is still a stick. Have you made any clutch changes? How hard does it hit the tires on the starting line? Do the tires slip or dead hook? Does the rear suspension squat, or lift?

Raising or lowering the center of rotation (ladder bar eye) primarily affects the reaction of force applied to the rear tires.
Lengthening the center of rotation affects the point of lift in relation to the longitudinal center of gravity, not an option for your ladder bars.

[Mark Yacavone]

Originally Posted by Tom Broome

I'll try to keep this short.
You lowered your car and it doesn't wheelstand as much. When the center of gravity is lower in relation to the rear axle the car will not transfer weight as easily.
Did you lower the front at the same time?
I expect the solution can be found in the front suspension. How much travel? How much stored energy? What is your front spring rate?

I'm assuming your car is still a stick. Have you made any clutch changes? How hard does it hit the tires on the starting line? Do the tires slip or dead hook? Does the rear suspension squat, or lift?

Raising or lowering the center of rotation (ladder bar eye) primarily affects the reaction of force applied to the rear tires.
Lengthening the center of rotation affects the point of lift in relation to the longitudinal center of gravity, not an option for your ladder bars.

Very good post.Hope to see more.

[joespanova]

Originally Posted by Tom Broome

I'll try to keep this short.
You lowered your car and it doesn't wheelstand as much. When the center of gravity is lower in relation to the rear axle the car will not transfer weight as easily.
Did you lower the front at the same time?
I expect the solution can be found in the front suspension. How much travel? How much stored energy? What is your front spring rate?

I'm assuming your car is still a stick. Have you made any clutch changes? How hard does it hit the tires on the starting line? Do the tires slip or dead hook? Does the rear suspension squat, or lift?

Raising or lowering the center of rotation (ladder bar eye) primarily affects the reaction of force applied to the rear tires.
Lengthening the center of rotation affects the point of lift in relation to the longitudinal center of gravity, not an option for your ladder bars.

Nothing has changed except the ride height in the rear..........IIRC.
Mark seems to know you................?

[Mark Yacavone]

Originally Posted by joespanova

Nothing has changed except the ride height in the rear..........IIRC.
Mark seems to know you................?

No, I don't, but he seems to know something about chassis (plural) and suspensions

[jerry witzel]

On my 68 Camaro the front of the ladder bars are angled downward, it always leaves with the wheels up. The 66 Nova I used to own had the front of the bars angled up when I first bought it and it had no adjustments. I had a guy weld new brackets on it and angled the front of the bars downward. The first race with it like that it broke 1 rear shock and cracked both upper shock mounts. I was always under the impression that with them angled downward it would leave harder. I do know that front and rear ride height can really effect weight transfer.