who's running ladder bars mounted to the frame rails.

I have a set mocked up on my a roadster. I'm considering scrapping them in favor of the triangulated bars but am worried about interference between the trans/driveshaft and crossmember as well as interference between the ladder bars and frame rails. I'm familiar with the drawbacks of mounting to the side, but have seen many pictures as well as a similar setup in the speedway catalogue. Any rreal world horror stories?

 

Well,I have one. I was following a friend in his model A tudor. We had been to a show and he had his wife and two kids in it. The forward attachment bolt on the left side sheared. The car swerved and went across the highway to the other side and into the other lane. Brakes made it swerve back to the right and almost turned over. It ended up in the ditch on the side of the road. Inspection later showed ALL the bolts were failing.

 

Glad you're still here with us Andy, scary stuff for sure. That pretty much confirms the doubts I've had with my stetup. I feel like I'm running on a treadmill with this project and was hoping for confirmation that side mounted ladder bars weren't so bad. Best to do it right while I can.

 

do you mean like this this makes me wonder did your freind have grade 8 bolts what would cuase it ,id like to know so i dont get killed

 

My car is setup like that and those bolts are freaking huge that go through the heim end, well if you were using the ball joint type bolt like on wishbone mounts. Then I could see a failure maybe.

 

I guess the biggest issue would be that the bolt is in single or double sheer. Mine as of now is in single sheer with a block welded to the frame and tapped for the bolt. I plan to add a triangle piece to the frame in front of the forward mounts coming back to the inside of the hiem joint to put the bolt in double sheer.

I know alot of guys run them in single sheer and have had no problems. My luck dont run that way.

Heres a pic of mine in its current state

 

How does the body roll with parallel ladder bars ?


Doesn't matter how big the bolts are,sooner or later,something will give.

 

I think all this got stated by copying old race cars.They had parallel bars on the outside of the frame. The part that gets lost is they were running torque tube drive line like the old Chevy's and live rear axles. With a live rear axle there are no axle bells. The radius rods were in bearings running on the turning axle.

 

I run cone spacers on each side of my heim to give it more flex.

 

this is what i have , speedways brackets , welded on you cant see but i have it reinfored in the back but now im worried im thinking they mit snap right off after reading this

 

I am confused on exactly what your still going to do. Can you explain what single vs. double sheer is for me?

 

Here's a shot of my rear and it is double shear, the moving part (heim end) is locked in batween two other pieces. Think of the heim and the bracket being a big pare of siccors, one moves up, the other down and it shears the bolt. Two brackets and one heim, double shear.

 

I had ladder bars mounted straight with the frame on my GMC pickup. It seemed to work OK...until it failed!

Like has been said before, with a set up like that, it forces the axle housing to act like a torsion bar. Eventually something will fail. My axle housing split.



I pointed the ladder bars in toward the center...



...and now everything moves like it should.

Neal

 

Thanks for posting this up. The way it has been explained to me is that when a bolt is put into double sheer you are in theory dispersing the load on the bolt more evenly. whereas is single sheer the bolt is not "captured" on both sides thus causing greater force to the uncaptured side. I might be overengineering it but thats my take...

 

I origionally had a set of Pete and Jakes Triangulated Ladder Bars under my 32 but with the heavy Z in the rear I ran into all kinds of interferance issues. So I scrapped it for what Im building now. I may sometime down the road go with a multi link set up. I probably should have but this is what I'm going with for now...

 

Holy shit!

I bet you had to change your shorts after that incident. thanks for thinput an phots guys this helps.

 

Ok, so would it not be recommended to mount 24" ladder bars outside the framerails angled towards the frame with clevis' on the axle end and tie rods on the frame end?

 

thats what i wanna know thats what i have. now im wondering

 

I haven't mounted mine yet, that's why I'm asking...I'm not going to mount everything that way and find out it doesn't work...so does it work with clevis' and tie rod ends?

 

Everytime this comes up someone has a simliar photo or story and some other people say they have been doing it for years with no problems.

If you have limited suspension travel or bushings on the ladder bar ends that allow a bit of twist, you may get away with it for longer.

Look at NealinCA's pic and decide for yourself - do ya feel lucky

 

now in a ideal world i know that the focus point of the ladder bars should be at the ujoint at the trans, but this isn't always possible. so how far off of that point can you have the bars split?

 

Holly Shit!!!
You have a death wish!!
Get rid of that design or just weld it all solid so it does not break off.

 

Is there anyone here with a serious reply that has any recommendations, or are you all just a bunch of jackasses with half answers? Clevis' and tie rod ends on 24" angled ladder bars, yes or no...and what works better?

 

I am sorry that I was blunt. 24" is way short. You will get a lot of wheel hop in addition to the danger of breaking something. I have used very low mounted bars from '39 Old's and also 35-36 Ford bars. 2x 3 tubing would also work if thick wall. Just mount them low and bring them close together in front. 6" or so apart maximum. Tied together like Henry did is best!!!. Mounting them low actually reduces the bending stresses in them. Any bars monuted to the outside of the frame or just far apart in front is a diaster in the making. Be SAFE!!!

 

Before I saw this thread, I was been looking at Chris Alston's Chassisworks ladder bars this morning.

http://www.cachassisworks.com/Stories/TechCAC-003_WEB.pdf

Their catalog suggests using urethane ends on ladder bars for the street.

So I emailed them about triangulating the bars in conjunction with a tranverse mounted spring. I don't think they understood the question. Here is their reply:

"The urethane front mount only works good with the ladders straight. If you triangulate them they wear faster.I would just run them parallel with a locator or panhard bar, use the transverse leaf"


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Thanks Andy, but if mounting outside the frame is dangerous, then how do rear radius rods/hairpins work without failing? I've seen numerous hairpin setups like what I want to do with the ladder bars I made...is there a safer way to mount my ladder bars?

 

There was a thread a while back that had a workable solution. They pivot mounted the bars on both ends. The axle wrap up was absorbed by a central torque arm simular to a Camero or a sprint car. The central bar has to be shackled at the fron if it is not in line with the front mounts for the radius rod/trailing arms. I used this design on my 375 FI 327 Chevy II in 1965. The arm was a 39 Olds. It worked great. You need to have any arms at least 32-36 inches long

 

I'm talking about a 190hp 2400lb car though...it just seems to me that if hairpins work on the rear, then the ladder bars will too if you copy the setup...on my bars the bars themselves are 24" long, I still have to add threaded bungs and hardware, they should be at least 30" long after that...