axle wrap

bajascott · Post by **bajascott** » Sat Aug 20, 2011 8:40 pm

so heres the deal,...short story then questions.............
so i decided to run my bronco in a local tuff truck event figuring i built the the thing to use,why not have a little fun locally.... so i prep it and all is good to go.
i recently replaced my rear springs with a custom pack that i got from a member here and installed them set the pinion angle ,limits and bumps up accordingly did some garage driveshat mods etc....
i ge to the line up green flag drops i put a nice size dent in my floor board,hit the first jump and bang......along with a few more bangs...my yoke broke in two and i was done.
my buddy said that my tired hardly left the ground and when i caught traction it went.
so on to my question about axle wrap.
i have heard good and bad from alot people and want to know the skinny on 2-links.
i have been told to look into doing some sort of shackle in the front and hiem in the rear.
my thought is measure the distance from the center of the front spring bolt to the centering pin and use these measureme for length and then keep it paralell to the springs. i have never built a 2 link before and want to get this thing working right.so i can run it for a while before i sell out and 4 link it.
give me your thoughts,pictures and advise. thanks

tcm glx · Post by **tcm glx** » Sat Aug 20, 2011 9:08 pm

Scott......
I cant tell you squat about the lenghts, how to build them, etc etc.

I did drive my brother burgundy bronco pre 2 link, and could immediatly tell in the difference both on the street and in the dirt compared to mine with the 2 link. Much more positive response, etc etc...

I really dig it, Keifers kit is heim on both ends, and it is nice!

Nick · Post by **Nick** » Sat Aug 20, 2011 9:10 pm

I love my 2 link! The truck hooks up, and just has a more stable feel. Mine is set up with bushings, Keifer uses heims, i never heard of using a shackle. Here is a pic of mine.

PaulW · Post by **PaulW** » Sun Aug 21, 2011 8:06 am

Recommend the 2 link - why?
The leafs for longer travel than stock means the leafs are being subjected to more flexing. This means much shorter life.
The extra 2 link limit the "S" flexing of the leafs which is much worse than the normal flex due to cycling.
Before I went to coils I was replacing the leafpacks every year. And I had perfectly designed 2 link setup.
However it is true with custom main leaf ends with military wrap the leaf pack life can be extended.

Its possible the reader can present arguements as to why leafs/leaf packs fail, but the physics still rule and that is the more a leaf flexes the quicker it wil fail. Wash borads and whoops are the root cause for leaf spring failure.

Bottom line is get special ends on you leafs and always use the 2 link setup.
PaulW

BDKW1 · Post by **BDKW1** » Sun Aug 21, 2011 9:07 am

PaulW wrote:Bottom line is get special ends on you leafs and always use the 2 link setup.

Go tell that to Chris..........

78Class3 · Post by **78Class3** » Sun Aug 21, 2011 9:41 am

This may be the wrong place to ask this question but.....If you have a two link setup, then as the axle drops and the two link swings in its natural ark , wouldn't this want to make the axle pull forward as it droops? If that is the natural tendency of a leaf pack to begin with as the axle droops it pushes forward then I can see how the two link would work in concert with it, however if that is not its natural tendency then wouldn't the two link be fighting the axle articulation? Just my brain trying to conceptualize it.

bajascott · Post by **bajascott** » Sun Aug 21, 2011 10:38 am

keep it coming.......more

PaulW · Post by **PaulW** » Sun Aug 21, 2011 12:24 pm

BDKW1 wrote:
PaulW wrote:Bottom line is get special ends on you leafs and always use the 2 link setup.
Go tell that to Chris..........

====
He may be a beliver now. Lost both leaf packs Sat. in SF
PaulW

PaulW · Post by **PaulW** » Sun Aug 21, 2011 12:44 pm

Yup, easy answer.
When the links are designed wrong they fight the leafs and make the problem worse.
Place the pivots correctly and the links have no effect on what the spring does for normal compression and extension. All they are for is axle wrap. Its all about measuring and cycling. Just another geometry problem to solve.
Spirit did mine and being the sketpic that is my nature I went ahead and drooped the thing out and sure enough the links came out with little effort. A test that was good enough for me. Of course it would be better if I additionally had a way to suck the truck down to the bumps to see if the links were free for that case. If I ever build another shop I will include a link in the floor so I can check compression without removing the springs. Which is what I do these days. That method really sucks and is dowright dangerous.

Bottom line get links done by a pro that cycles them to verify they are correct. This is especially important if you have messed with the spring attachments.

Alas there is a good reason for switcheing to coils. and all this tech stuff about leafs becomes just history.

BTW, one can design these links so that the axle rotates for a rock crawler wanting to get rediculous travel and the u-joints become the limiting item. Guess what . That guy will be buying leaf packs even faster than described above.
PaulW
===============

78Class3 wrote:This may be the wrong place to ask this question but.....If you have a two link setup, then as the axle drops and the two link swings in its natural ark , wouldn't this want to make the axle pull forward as it droops? If that is the natural tendency of a leaf pack to begin with as the axle droops it pushes forward then I can see how the two link would work in concert with it, however if that is not its natural tendency then wouldn't the two link be fighting the axle articulation? Just my brain trying to conceptualize it.

PaulW · Post by **PaulW** » Sun Aug 21, 2011 12:54 pm

Stay with leaf springs and replace them for every race an carry 2 spare leaf packs during each race. With the links you might even finish the race before replacing the leaf pack.
For hard use prerunner, just replace the leaf packs with new ones every year like I did for many years.
Extend spring life to 2 years and you will come home on the bumps.

From an enginnering point of view - Flex a spring and it will fail. The more times you flex it and the more extreme the deflection the quicker it will fail.
PaulW

bajascott · Post by **bajascott** » Sun Aug 21, 2011 1:28 pm

i will build the links myself,i know i am confident that what i build will last. this is the first time i have had a failure on any thing i have built that resulted in having a tow truck. there is a 4 link in the future on my bronco but for now i need it to work well for the rest of this year, i have alot of roads and trails that will be traveled so we can have our race up here in eastern oregon.
i wish i could go to phx and help out with daves class 3 and steal his design.i know his works and have heard great words from one his prep guys about his prerunner.....

BDKW1 · Post by **BDKW1** » Sun Aug 21, 2011 1:57 pm

If your building your own links, My personal preference is urethane bushings on the frame end and hiems on the axle end.

bajascott · Post by **bajascott** » Sun Aug 21, 2011 2:02 pm

thats what i was thinking too.

PaulW · Post by **PaulW** » Sun Aug 21, 2011 2:17 pm

Urethane urethane The voided kind. Weld one end cycle to full droop tak weld other end. Repeat. Done.
PaulW

Post by **SteveG** » Mon Aug 22, 2011 8:33 am

PaulW wrote:Spirit did mine and being the sketpic that is my nature I went ahead and drooped the thing out and sure enough the links came out with little effort.

I did the same test with mine (Autofab) during installation as well except I removed all but the main leaf and added a block to make up the difference. The geometry was just as John said... really good through the middle 12-ish inches of travel and pretty good during the rest of the travel (in both directions). Even beyond the middle 12" of travel I only remember 1/8", maybe 3/16" of misalignment between the bracket and bushing.

Post by **SteveG** » Mon Aug 22, 2011 9:09 am

Jeff Huseman (I think his name is Jeff) had a "beater" short course Ranger with a cool rear "link" set up. It basically turned the rear suspension into a 3-link with leaf spring lower links. The leaf/axle pivot would need to be moved fore or aft the axle to keep lift to a minimum, but it would be fun to play with.

Here is my Kindergarten level drawing of it.

ChaseTruck754 · Post by **ChaseTruck754** » Mon Aug 22, 2011 9:26 am

The Husemans (there are 3 brothers I believe) do some cool, different stuff!

Dust · Post by **Dust** » Mon Aug 22, 2011 11:26 am

SteveG wrote:Jeff Huseman (I think his name is Jeff) had a "beater" short course Ranger with a cool rear "link" set up. It basically turned the rear suspension into a 3-link with leaf spring lower links. The leaf/axle pivot would need to be moved fore or aft the axle to keep lift to a minimum, but it would be fun to play with.

Here is my Kindergarten level drawing of it.

In my experience, from a wheel hop perspective (which is generated by wrapping the spring into a "S" shape and having it snap back) locating the link above the main leaf will actually have no effect or even increase the problem.

PaulW · Post by **PaulW** » Mon Aug 22, 2011 12:09 pm

http://classicbroncos.com/forums/showth ... p?t=189674
An interesting concept?????
PaulW

Polarcub · Post by **Polarcub** » Mon Aug 22, 2011 4:32 pm

PaulW wrote:http://classicbroncos.com/forums/showth ... p?t=189674
An interesting concept?????
PaulW

Paul great read....I am not overly educated on this subject but will the single "link" on the drivers side control the wrap as well as a standard 2 link across the whole rear end?

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