Rocker/pushrod suspension tech

[Donuts1]

Well, we started talking about rocker/pushrod suspension design in Bustedknucle's build thread, but thought I would start a new thread since the info was so good. Thanks again Busted!!!
Here are the pics of Busted's setup...

I'm going to just copy and paste the earlier conversation to get everyone up to speed of where we are at.

What are you doing for your center support bearing? How did ya come about the distance from the center support to the pushrod center mount, and what kind of ratio did ya make the pushrod to bag movement? Thanks in advance!!!

I used a bushing that the truck guys use, its made of .188 thick steel DOM pipe with a massive composite center (WAY STRONG). There is a place here in CA that sells them, I think they were around 30.00 for 2. I first got the bags, they have a fully extended lenght and a collapsed lenght. Now with that you can figure your travel or for a better word your bag movement. Figure out how much room you have and find center of that, remember your bags have a fully collapsed lenght that cant change use that when making the mounting point ( you dont have to run the bag fully exstened you can use your cam ratio for that) Try to keep the bags at a 45 degrees or better, if you lay them horizonal they will start to sag in the middle. Mount the cam so it wont hit the bag or mounting support, you can get pretty creative here so what ever you think will look good will probably work. Now for your cam ratio. Figure how much travel you want your truck to move. Lets say 6 inches...Lets say your bag can only move 4 inches that means your cam has to have a ratio to make up the other 2 inches to get you 6 inches you wanted. To find that, take a diameter measurment times pie (3.14) and divide it by 4. You will get your ratio movement you need ( YOUr CAM SHOULD NOT HAVE MORE THAN A 1/4 CIRCLE TRAVEL) EXAMPLE--look at the clock 12 to 3----3 to 6---- 6 to 9--- you get the picture. Once you have got that make your rods and mounting brackects and there you go. Its not that hard, if you gave me your travel I could figure your ratio out for you or walk you through that part. If you post a pic of what your trying to do I would have a better idea of how to mount the center. I hope this helps.

Curt

WOW! I would say you have definitely been studying this. I am actually running coilovers with 4 inches of travel and was only figuring the same 4 inches for suspension travel, so I was going to make my rocker lengths the same for the pushrod and the coilover. Didn't really know what to make that length though. So far I have built a bearing assembly for the center pivot and started mocking a few different length arms to it, but would love to find out the arm length I actually need...lol! Anyways, here are a few pics and all info is appreciated!

The bearing assy....

 

[Donuts1]

And the mock up...

 

[Unkl Ian]

IIRC, we used Bronze bushings on the
push rod set up we did; 20 years ago.

 

[Donuts1]

IIRC, we used Bronze bushings on the
push rod set up we did; 20 years ago.

You have any problems with them wearing out? I used cone bearings hoping to free up the rocker and have a long life. You have any pics?

 

[BUSTEDKNUCKLE]

Donuts, that looks really good. It looks like from the pic that you will have enough cam lenght on the rod side to get you 4 inches. Would like to see the spring connected. How do you have your axel connected to the frame? You may have already did this, but you can take some dividers and swing and arc with the measurement you have on your cam to double check everything before cutting and welding.... Looks really good... you sure have some skills there![cl

Curt

 

[Donuts1]

Donuts, that looks really good. It looks like from the pic that you will have enough cam lenght on the rod side to get you 4 inches. Would like to see the spring connected. How do you have your axel connected to the frame? You may have already did this, but you can take some dividers and swing and arc with the measurement you have on your cam to double check everything before cutting and welding.... Looks really good... you sure have some skills there![cl

Curt

Will get some pics when I get the coilovers in place and see what ya think. I built a triangulated 4 link out of 1 3/8 7075 aluminum. I'm just tacking stuff in place to see what works best. Here are the pics....