Leaf spring setup ?

As you might now I have a 93 F150 that I hope to be drag racing soon. I have swapped out the 8.8 for a 9" and 3.50 gears and 29.5 tire.

My question revolves around the link / traction bar setup. I plan on building my own but I need to know how the link / traction bar effects the suspension. I have been told that the bar needs to be atleast 1/3 of the wheel base. Should I try to build it parrel to the ground?

The setups that are sold over the internet just bolt to the bottom of the leaf springs and use a bolt-on frame bracket. Where I want to weld a bracket to the axle almost like a ladder bar.

I have never seen one run parallel to the ground. They usually mount below the axle and below the front spring mount making them parallel to the spring. I made my own in the Pinto. Made some tabs and welded them to the leaf spring plate and made the front to plates that bolt to the front leaf spring mount. My bar length was the same as some 4 link bars I had so I just used them. If it ever stops raining I will try and get you some pics.

As far as ride it made the ride rougher but I didn't mind it.

Good luck

Something very simular to this.

http://www.teamjdm.com/shop/product_info.php?products_id=79

Instead of mounting the front bracket to the frame I was going to make a mount off my driveshaft safety loop.

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Can any one tell me what the physics you have to over come to drage race a leaf spring suspension?
Is it just the simple fact that you want to keep the axle from moving fowards and backward?
Limiting it to a perfect up and down spring travel?

fordman460 wrote:preview.php?i=1&u=14459390][/url]

Wouldn't that setup allow a little slack for foward and backward movement.

something like a housing floater. The spring allows the axle to move forward and back when it goes through it's up and down travel. A solid mount would create binding during this travel. What you are trying to prevent, with a bar like this, is called spring wrap up.

My slapper bar ser-up has worked well for the 8 years I have had them. Very simple and the suspension doesnt bind like the long bar set-up. We put Cal-tracs on my dads 95 and havent got them to work very good as of yet but I really just put them on and set the preload as recommended for the base setting. Im sure they will work great once I mess with them. Biggest problem is the front doesn't lift to transfer weight. I have 90/10s but it wont come up in the front like my truck. It did get a 1.62 60 ft on a 150 shot but I didnt leave on the bottle.

You mention the binding on the long bar setup. Do you have any more info on this, go into more detail, what have you heard?????

I think he may be referring to the bind you would get without a housing floater or link on the front mounting point like I posted.

jones wrote:You mention the binding on the long bar setup. Do you have any more info on this, go into more detail, what have you heard?????

When you hook the long bars up they are solid to the front of the frame. They dont pivot like a caltrac bar so when the suspension tries to go down in the rear the bar tries to push the rear backwards. It seems to make them stiff.

i am going to attempt to build a set of ladder bars for my 63 stepside with leafs bought some plans off evilbay , will let you know how it works out. does any one if longer/shorter is better?

droppedf100 wrote:

jones wrote:You mention the binding on the long bar setup. Do you have any more info on this, go into more detail, what have you heard?????

When you hook the long bars up they are solid to the front of the frame. They dont pivot like a caltrac bar so when the suspension tries to go down in the rear the bar tries to push the rear backwards. It seems to make them stiff.

If you wanna run a 4 link, 3 link, or ladder bar, think about this for a few seconds. What is at the rear of the leaf springs???
Ford had it figured out in the early 60s, And we can't figure it out today??? Come on, it ain't rocket surgery...

hillbillyerv wrote:i am going to attempt to build a set of ladder bars for my 63 stepside with leafs bought some plans off evilbay , will let you know how it works out. does any one if longer/shorter is better?

I ordered a set of those plan too! haven't got them yet, only been a couple day's. My understanding is longer for mud, which is what I run in and shorter for asphalt,and in mud they should be parallel with the frame

jones wrote:Can any one tell me what the physics you have to over come to drage race a leaf spring suspension?
Is it just the simple fact that you want to keep the axle from moving fowards and backward?
Limiting it to a perfect up and down spring travel?

It can't move forward and backwards because the front pivot point on a leaf spring is fixed. Just the rear can move (because of the shackle) to compensate for change in distance because it pivots off of the front mount.

Here is some info I found while looking for some pics.

http://www.afcoracing.com/tech_pages/leaf.shtml

http://www.competitionplus.com/2004_10_21/chassis.html

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fordman460 wrote:[url=https://servimg.com/image_[url=https://servimg.com/view/14459390/2]

The reason the shackle is on the front of the torque arm (red bar) is to compensate for the difference in pivot points between the torque arm and the leaf spring. This type of suspension would be considered a 3-link.

Jones, I know you said you were building your own, but my cousin's S 10 drag truck that I have been tuning and driving has a 9" with leafs and uses Slidealinks. They do a good job and are very easy to adjust although they were on the truck when they got it with no instructions. I have just been guessing at it, but even at that they do a good job with no binding.

the travel arc or pattern is different for bars verses leaf springs.therefore floaters are neededto let suspenion travel with out binding .