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Ladder bar set up help ( D150Truck) #3055960
07/04/22 07:47 PM
07/04/22 07:47 PM
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west palm beach, florida
modelmakerinc Offline OP
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Guys, I am wanting to double check the layout before I get too far along.

I have the chassis at ride height, i have 3.5" of clearance from the axle to the framerail, the axle brackets are 90* To the ground , the Ladder bars are at 2.5* nose down , but the top of my front hangar bracket is 3/8" below the frame rail.

Three questions,#1 is 3.5" enough clearance above the axle? ( single adj. CoilOvers) or do I need to c notch the framerail ?

#2 the front hangar bracket and crossmember? What is my best option for tieing into the frame? Longer brackets? mounting the crossmember below the frame rail and gusset? Combo of both,?


Options opinions please wink

#3 this is completely wrong and I put it together upside down? Kidding.

20220704_112934.jpg20220704_112318.jpg20220704_123908.jpg20220701_102805.jpg

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Re: Ladder bar set up help ( D150Truck) [Re: modelmakerinc] #3055976
07/04/22 08:48 PM
07/04/22 08:48 PM
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Romeo MI
MR_P_BODY Offline
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Is this a race truck or for the street.. a ladder bar is more violent coming off the line.. I had to make
lower holes for the fronts.. your rears are right side up
wave

Re: Ladder bar set up help ( D150Truck) [Re: MR_P_BODY] #3055982
07/04/22 09:25 PM
07/04/22 09:25 PM
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west palm beach, florida
modelmakerinc Offline OP
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Mr P Body,

It's my nephews truck, it will be mostly street driven, but surely will see at least some track time but its not a "Race Truck" YET up


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Re: Ladder bar set up help ( D150Truck) [Re: modelmakerinc] #3055996
07/04/22 10:15 PM
07/04/22 10:15 PM
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Romeo MI
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Thats the main issue,, a street truck needs a bit more rear end travel unless he likes it stiff
a race truck on ladder bars likes a stiff rear shocks
wave

Re: Ladder bar set up help ( D150Truck) [Re: modelmakerinc] #3056002
07/04/22 10:22 PM
07/04/22 10:22 PM
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Frostbitefalls MN (Rocky&Bullw...
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A rough guestimate of neutral line will be from the bottom center of the rear tire to the center of the camshaft at the front of the motor. It would be great to have at least one front adjustment hole below that line. I would start with a setting of one hole above the neutral line. Before final welding make sure you have enough adjustment to use all the holes. Box the housing brackets so they won't fold over (like mine did) if the vehicle gets out of shape. Invest in shocks consistant with the power you will have. I strongly advise going one step better than you think you will need. I am on my fourth upgrade in rear shocks . A bigblock and torqueflite make for a brutal starting line senario as power climbs.


8.77 153 mph best, 3055 lbs 528 indy 440-1 alky
Re: Ladder bar set up help ( D150Truck) [Re: gregsdart] #3056222
07/05/22 12:28 PM
07/05/22 12:28 PM
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west palm beach, florida
modelmakerinc Offline OP
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Thank you, im still looking at the overall before committing to cutting so appreciate all the info. there are so many nuances to installing correctly.


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Re: Ladder bar set up help ( D150Truck) [Re: modelmakerinc] #3056275
07/05/22 01:40 PM
07/05/22 01:40 PM
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west palm beach, florida
modelmakerinc Offline OP
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From Chassis Engineering ( Kit maker)




quote". Trucks, unless lower quite a bit, can be a little cumbersome to ladder bar or four link. The frame just isn’t designed like a passenger car frame.
This truck in the attachment, we c-channeled to get it down some and help with the install of ladder bars. As you can see we still added a section of box tubing to the rails. The problem with I think you want to do, is now the force forward and up on the brackets is dropped way down below the crossmember and puts and undue load on the cross member. This load will work at twisting the cross member and possibly rip and or fatigue it. "

this is what i sent him I may do and his response

lb1.jpglb2.jpg

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Re: Ladder bar set up help ( D150Truck) [Re: modelmakerinc] #3056302
07/05/22 02:14 PM
07/05/22 02:14 PM
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On the parachute mount
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i would slip the box tube into the brackets, cut the bracket so the box tube is flush with it. weld all that to the bottom of the frame rail. put 1.25 tube gusset from the inside bracket to the box tube. plate the brackets on the front and put a 1.0 gusset from the plate to the bottom of the frame. Set the ride height with the bars level in the middle hole, this will give you adjustability up and down later on.


....BAD A$$ STREET CAR.....
Re: Ladder bar set up help ( D150Truck) [Re: n20mstr] #3056575
07/06/22 09:55 AM
07/06/22 09:55 AM
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Originally Posted by n20mstr
Set the ride height with the bars level in the middle hole, this will give you adjustability up and down later on.

This is the most important. I would not have the bars pointing down as in your drawing unless you want a wheelstander.

Re: Ladder bar set up help ( D150Truck) [Re: fbs63] #3056607
07/06/22 11:32 AM
07/06/22 11:32 AM
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west palm beach, florida
modelmakerinc Offline OP
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Quote
This is the most important. I would not have the bars pointing down as in your drawing unless you want a wheelstander.


lowering the front bars softens the hit on the tires, raising them adds BITE. And I am using the geometry spelled out in the manufacturers instructions FOR INITIAL set up. when the truck is finished the tuning will dictate where it goes


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Re: Ladder bar set up help ( D150Truck) [Re: modelmakerinc] #3056669
07/06/22 12:53 PM
07/06/22 12:53 PM
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On the parachute mount
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Raising the bar hits the tire harder, and increases chassis seperation, lowering the bar hits the tire softer and decreases the seperation. NO matter what , you are never getting rid of the seperation in a ladder bar suspension. THere will always be rise or seperation, thats why you need a GOOD shock with a ladder bar and a lot or decent power. For a daily driver or part time street strip car like this, i would put the bars level and adjust them at a test session depending on what the car does with the power it has.


....BAD A$$ STREET CAR.....
Re: Ladder bar set up help ( D150Truck) [Re: n20mstr] #3056694
07/06/22 01:34 PM
07/06/22 01:34 PM
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west palm beach, florida
modelmakerinc Offline OP
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N2Omstr iagree100% agreed thats what i said whistling. albeit, differently smoke


this is my modified bracket, the notch on the bottom is for a kicker (brace) to the frame rail about 14" forward of the crossmember
sorry for sideways pic

mod LB brcket.jpg
Last edited by modelmakerinc; 07/06/22 01:40 PM.

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Re: Ladder bar set up help ( D150Truck) [Re: modelmakerinc] #3056698
07/06/22 01:44 PM
07/06/22 01:44 PM
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On the parachute mount
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n20mstr Offline
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Originally Posted by modelmakerinc
N2Omstr iagree100% agreed thats what i said whistling. albeit, differently smoke


this is my modified bracket, the notch on the bottom is for a kicker (brace) to the frame rail about 14" forward of the crossmember
sorry for sideways pic



My idea of "street cars" with big block involves a boatload of nitrous and single digit time slips..... whistling
I also like low sitting cars trucks. That being said id trim the top of that bracket until the box tube was equal with the top (if that makes any sense)
Also, pay attention to the ride height of the shock when setting this up. Make sure the brackets on the rear housing give you a lot of adjustment without lowering or raising the truck. Down the road if you get serious you will want a 15" ride height shock in there.... up Sounds like a cool project


....BAD A$$ STREET CAR.....
Re: Ladder bar set up help ( D150Truck) [Re: n20mstr] #3056797
07/06/22 04:21 PM
07/06/22 04:21 PM
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Frostbitefalls MN (Rocky&Bullw...
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[quote=n20mstr]Raising the bar hits the tire harder, and increases chassis seperation, lowering the bar hits the tire softer and decreases the seperation. NO matter what , you are never getting rid of the seperation in a ladder bar suspension. THere will always be rise or seperation, thats why you need a GOOD shock with a ladder bar . [/quote
I have a ladderbar, 30 inch, 106 wb, 3000 lb and in the bottom hole i am below the neutral line, and get no rise. The proof of this to me came when i had the front mount ON the neutral line. Due to torque roll the left ladderbar geometry went ABOVE the neutral line, and the right rear went BELOW it. All he!! Broke loose and the result was the car ripping the left rear off the track ( observed) when it ran out of shock extension and the car up on only the right rear for an instant. I run an anti roll unit now that is very beefy as i bent the first one on the first pass. I have posted the math on the forces at work on the hit. Over 20 times engine torque on the hit at the axles with a 2.45 low and 4.56 gear.
For sure though, lots of shock control needed the instant those bars are above the line.

Last edited by gregsdart; 07/06/22 04:25 PM.

8.77 153 mph best, 3055 lbs 528 indy 440-1 alky
Re: Ladder bar set up help ( D150Truck) [Re: modelmakerinc] #3056905
07/06/22 09:31 PM
07/06/22 09:31 PM
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I would start it out in the bottom hole and adjust the shocks to get the best 60 Ft and reaction times and then move it up to the next hole and test some more scopewrench up
Only one way to get better and faster, test, test and test some more up


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Ladder bar set up help ( D150Truck) [Re: Cab_Burge] #3056939
07/06/22 11:16 PM
07/06/22 11:16 PM
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dvw Online content
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If the bar is level/down/up to the ground actually means squat. Where the front mount hole lays on the anti-squat line determines what the suspension will do. If it's above the anti-squat line it will separate. If it's below the anti-squat line it will squat. With most available rear ladder bar housing brackets this point usually ends up with the bar being level to the ground. That's why most people say level to the ground is a good staring point. but in fact it's a guess. Lengthen or shorten the bar? That point now needs to go down (shorter bar) or up (longer bar) to remain on the center of the Anti-squat line. Personally I'm not a fan of ladder bars on the street. A ladder bar set-up is a giant anti-roll bar. The housing can't roll rotate going around corners or up steep inclines while turning. This puts a lot of stress on joints, mounts, welds, and the bars themselves. It also induces over steer in hard cornering. Can it be done? Yes. But Caltracks or a 4 link is a better option for the street. Track only? They work great. As far as gusseting. I'd triangulate the front cross member at a 30-45 degree angle forward to the frame. Also nice to have the cage bars land on top of the ladder bar mount.
Doug

Re: Ladder bar set up help ( D150Truck) [Re: dvw] #3057042
07/07/22 09:18 AM
07/07/22 09:18 AM
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Originally Posted by dvw
If the bar is level/down/up to the ground actually means squat. Where the front mount hole lays on the anti-squat line determines what the suspension will do. If it's above the anti-squat line it will separate. If it's below the anti-squat line it will squat. With most available rear ladder bar housing brackets this point usually ends up with the bar being level to the ground. That's why most people say level to the ground is a good staring point. but in fact it's a guess. Lengthen or shorten the bar? That point now needs to go down (shorter bar) or up (longer bar) to remain on the center of the Anti-squat line. Personally I'm not a fan of ladder bars on the street. A ladder bar set-up is a giant anti-roll bar. The housing can't roll rotate going around corners or up steep inclines while turning. This puts a lot of stress on joints, mounts, welds, and the bars themselves. It also induces over steer in hard cornering. Can it be done? Yes. But Caltracks or a 4 link is a better option for the street. Track only? They work great. As far as gusseting. I'd triangulate the front cross member at a 30-45 degree angle forward to the frame. Also nice to have the cage bars land on top of the ladder bar mount.

Doug



Doug is correct on this, i just say level because thats how i measure my car. IT depends on the car because if it has a serious rake, then the ladder bars are really pointed up when you measure them as level. Doug is correct in that the ladder bars should be set in correlation to the anti squat line. It can get a little tricky. A digital angle finder really helps. Also helps to set it on your rocker panel for a reference to measure the cars rake , as well as the ladder bar angle.
I hope i havent muddled this post up with this "technical" ladder bar info shruggy


....BAD A$$ STREET CAR.....
Re: Ladder bar set up help ( D150Truck) [Re: n20mstr] #3057589
07/09/22 05:07 AM
07/09/22 05:07 AM
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To further muck up the waters, a little math on neutral lines. If your truck has a high center of gravity, or higher than the average door car, then the neutral line will be steeper. Taking camshaft height as a guestimate of c. g., Say 28 inch? If your wheel base is 120 inch, and ladderbars are 30 inch from axle center to front pivot, then the neutral line at the front ladderbar hole would be a percentage of the wheelbase . Ladderbar length (30 in) devided by wheelbase (120?) equals . 25 of the wheelbase times the actual c. g. Of 30 inch. So that would be . 25 x 28, or 7 inchs off the ground. If my calcs are close, then IMHO I would place the front ladderbar mount with the bottom hole at 6 inch off the ground or maybe 6.5.
Since you will most likely be nose heavy, you will need to have rise. How much can only be determined by power, and the tires you run.
Last thought, consider boxing part of the frame rails, from the ladderbar mount forward maybe a foot or so?

Last edited by gregsdart; 07/09/22 05:11 AM.

8.77 153 mph best, 3055 lbs 528 indy 440-1 alky
Re: Ladder bar set up help ( D150Truck) [Re: modelmakerinc] #3057598
07/09/22 08:20 AM
07/09/22 08:20 AM
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Get you a good 4-link/ ladder bar program and calculate all the geometry before you weld anything. I use performance trends. http://performancetrends.com/4link.htm Just from the photos it looks good. I know this program has saved me a lot of work over the years.

Re: Ladder bar set up help ( D150Truck) [Re: jwb123] #3058131
07/11/22 08:42 AM
07/11/22 08:42 AM
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west palm beach, florida
modelmakerinc Offline OP
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Thanks Guys, all the input is very much appreciated.

I set the pinion angle 1.5* down which effectively rotated the axle housing up this in turn raises the front of the ladder bars one hole or will allow me to install the bracket a bit higher in the frame. I am still having taller brackets made for my application and install.

Over the next month or two my workload has increased significantly so I may only get a couple hours a week to get any progress done. I will take pics and post again when there is visible progress made.

Thanks Again fellas.

Henry


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