Front Wishbone Help

[JeepFreak21]

heims absolutely SHOULD be mounted with the bolt verticle for the end of a wishbone. they are much stronger that way.

now that's not to say that is couldn't work with the bolt mounted horizontal, especially if you use a 1" or bigger heim, but if you're building from scratch you might as well do it the right way the first time.

So, what if it's not a heim at the end of the wishbone? Beezil's first bushing was mounted with the bolt horizontal and I believe whatever it is he's using now is also mounted with the bolt horizontal.

[disclaimer]
I don't mean to keep using Beez as an example of the perfect setup, but his setup is the one I have pictures of for comparison... if I wanted to just copy his (or someone else's) junk, I wouldn't have opened this topic up for discussion.
[/disclaimer]
Billy

 

[vintagespeed]

That's really good to hear. Just for the record, what setup did you use for your hydro?
Billy

I ordered the steering valve & reservoir/filter from Sean (Station) @ www.performanceoff-road.com. It's a Danfoss valve. $475.

The lines are build yourself Goodyear lines and the cylinder is a Chief 2x8x1.125 model I got from Surplus Center. $60.

-jb

 

[vintagespeed]

[disclaimer]
I don't mean to keep using Beez as an example of the perfect setup, but his setup is the one I have pictures of for comparison... if I wanted to just copy his (or someone else's) junk, I wouldn't have opened this topic up for discussion.
[/disclaimer]
Billy

I liked Beez's setup except for the heims & the complex center link. Yes it'll give 360 deg. of rotation but it's long & it looks like the axle was moved forward a bit to compensate. I was originally going to mount a JJ with the bolt horizontally mounted and I didn't because I thought that sideloading may be an issue with the JJ. As it turns out, the sideloading isn't as big of an issue as I made it out to be.

-jb

 

[Beezil]

it looks like the axle was moved forward a bit to compensate.

102" of wheel base my man.

 

[JeepFreak21]

OK guys, anybody have any input on the ideal length for the upper wishbone?
Billy

 

[Willis]

So, what if it's not a heim at the end of the wishbone? Beezil's first bushing was mounted with the bolt horizontal and I believe whatever it is he's using now is also mounted with the bolt horizontal.
Billy

Pretty much any other joint you can mount with the bolt horizontally. For the Heim, you'd want the bolt mounted vertically because of the side loads. The balls of Heims are pressed into the bodys and with a horizontally mounted bolt, you are putting a lot of side load on the same plane the balls are pressed in. If you lay the Heims down (vertical bolt), the side loads are in the same plane as the front/rear loads, pushing the ball against the sides of the body. You can still do double sheer with a vertical bolt, you just make a pocket for the joint to slide into.

Steve

 

[sintax]

JB:

Any pics of your shock hoops?

I am really digging how you set everything up. I can't wait to take a look at it in person. I may have to steal some of your design ideas.

-Scott

 

[JeepFreak21]

OK guys, anybody have any input on the ideal length for the upper wishbone?
Billy

Nobody? Anybody have any good book recommendations? This aspect is somewhat vital.
Thanks,
Billy

 

[Willis]

Most books that cover the subject are race car chassis books, so you have to get a basic understanding from it, then convert it to a 4wd application. They also usually deal with independant front. How many race cars you know of with solid front axles? I wish there was a 4x4 specific chassis/suspension book.

If you do want to do some reading, Chassis Engineering by Herb Adams, Fundamental of Vehicle Dynamics by Thomas D. Gillespie, and Race Car Dynamics by Milliken and Milliken.

I have mine all drawn out for what I have planned with a parabolic upper. What I end up with is a 27" lower, and a 21.75" upper. I want some pinion change built in, and I get a total of 12* of change from full compression to full droop. I end up with about 70% anti-dive at 7" of lift. The more lift, the higher that number will go.

Have you read this?
http://www.naxja.org/forum/showthread.php?t=15764&

There's a lot of good tech others have supplied, they got me on the right track and really cleared some things up for me.

Steve

 

[vintagespeed]

Nobody? Anybody have any good book recommendations? This aspect is somewhat vital.
Thanks,
Billy

It's all going to depend on your mounting location for the frame ends. You really can't throw out a 'standard' dimension. You COULD (theoretically) mount the wishbone & LCAs at the center of the frame, making them somewhere around 4ft long.

The longer your links, the better your angles but the weaker the link is.

-jb

 

[vintagespeed]

Most books that cover the subject are race car chassis books, so you have to get a basic understanding from it, then convert it to a 4wd application. They also usually deal with independant front. How many race cars you know of with solid front axles? I wish there was a 4x4 specific chassis/suspension book.

If you do want to do some reading, Chassis Engineering by Herb Adams, Fundamental of Vehicle Dynamics by Thomas D. Gillespie, and Race Car Dynamics by Milliken and Milliken.

I have mine all drawn out for what I have planned with a parabolic upper. What I end up with is a 27" lower, and a 21.75" upper. I want some pinion change built in, and I get a total of 12* of change from full compression to full droop. I end up with about 70% anti-dive at 7" of lift. The more lift, the higher that number will go.

Have you read this?
http://www.naxja.org/forum/showthread.php?t=15764&

There's a lot of good tech others have supplied, they got me on the right track and really cleared some things up for me.

Steve

Yeah, I wish I'd read some good suspension books. I gleamed what I could from POR & my first setup was "trial & error".

Are you sure you want 12deg of pinion/caster change? Why? The pinion will be pointing away from the tcase at full droop making your driveline angles worse. Or am I missing it?

-jb

 

[Willis]

Are you sure you want 12deg of pinion/caster change? Why? The pinion will be pointing away from the tcase at full droop making your driveline angles worse. Or am I missing it?

-jb

At droop, the pinion rotates upward 6*, at compression, the pinion rotates down 6*. I will have my axle set up with about 12* of pinion angle. I want it to rotate down some at compression. One drawing I had, had the pinion angle not changing at all. So I played with link lengths and mounting points a bit.

Steve

 

[JeepFreak21]

Most books that cover the subject are race car chassis books, so you have to get a basic understanding from it, then convert it to a 4wd application. They also usually deal with independant front. How many race cars you know of with solid front axles? I wish there was a 4x4 specific chassis/suspension book.

If you do want to do some reading, Chassis Engineering by Herb Adams, Fundamental of Vehicle Dynamics by Thomas D. Gillespie, and Race Car Dynamics by Milliken and Milliken.

I have mine all drawn out for what I have planned with a parabolic upper. What I end up with is a 27" lower, and a 21.75" upper. I want some pinion change built in, and I get a total of 12* of change from full compression to full droop. I end up with about 70% anti-dive at 7" of lift. The more lift, the higher that number will go.

Have you read this?
http://www.naxja.org/forum/showthread.php?t=15764&

There's a lot of good tech others have supplied, they got me on the right track and really cleared some things up for me.

Steve

Yeah, I've read over that thread about 4 times now. Thanks for the numbers, at least that gives me a starting point.
Billy

 

[JeepFreak21]

It's all going to depend on your mounting location for the frame ends. You really can't throw out a 'standard' dimension. You COULD (theoretically) mount the wishbone & LCAs at the center of the frame, making them somewhere around 4ft long.

The longer your links, the better your angles but the weaker the link is.

-jb

I was asking because I know when researching 4 link rears, it's more important to get the length and angles and then make them fit (ie. cut the floorboards to get the mounts high enough), so I assumed that would be the approach for this also.
Thanks for the help,
Billy

 

[vintagespeed]

I was asking because I know when researching 4 link rears, it's more important to get the length and angles and then make them fit (ie. cut the floorboards to get the mounts high enough), so I assumed that would be the approach for this also.
Thanks for the help,
Billy

You could also lower the LCA mounts, it's about proper link separation not necessarily about cutting up the floor.

-jb

 

[vintagespeed]

At droop, the pinion rotates upward 6*, at compression, the pinion rotates down 6*. I will have my axle set up with about 12* of pinion angle. I want it to rotate down some at compression. One drawing I had, had the pinion angle not changing at all. So I played with link lengths and mounting points a bit.

Steve

I'd like to see the drawings if you have them in digital format. Just curious about your link mounting distances.

In most of my research for this & the last project I played with link lengths alot too. The original plan was to mount the wishbone & the LCAs at the same level inside the frame but there just isn't enough room & I didn't want to experiment any more with this build.

Another factor to consider in link setup is the axle mount locations. You never want your links to have a point in travel where all the axises line up.
It's kind of difficult to explain but when all the pivot points line up with axle center your link does nothing to control torque.

"O" is the axletube when viewed from the side, sorry for my crappy drawing.

O
.+===========+ - when the axle torques this arm will resist it.

O+===========+ - when the axle torques, this arm will do nothing.

If you follow the drawing, you'll see that in the second example the control arm will have no leverage over the axle torque and will depend on the other link (upper most likely) to control ALL of the torque load. This could overwhelm your design if you dont plan it in from the beginning.

In the first example the control arm can resist the torque generated at the axle center because it is mounted below & behind axle center. This means that the axle would have to move far upward in it's arc, outside of it's practical limits, for all the pivots to line up. It will always maintain torque control over the axle.

Hope that helps a little bit in your design.

-jb

 

[JeepFreak21]

I'd like to see the drawings if you have them in digital format. Just curious about your link mounting distances.

In most of my research for this & the last project I played with link lengths alot too. The original plan was to mount the wishbone & the LCAs at the same level inside the frame but there just isn't enough room & I didn't want to experiment any more with this build.

Another factor to consider in link setup is the axle mount locations. You never want your links to have a point in travel where all the axises line up.
It's kind of difficult to explain but when all the pivot points line up with axle center your link does nothing to control torque.

"O" is the axletube when viewed from the side, sorry for my crappy drawing.

O
.+===========+ - when the axle torques this arm will resist it.

O+===========+ - when the axle torques, this arm will do nothing.

If you follow the drawing, you'll see that in the second example the control arm will have no leverage over the axle torque and will depend on the other link (upper most likely) to control ALL of the torque load. This could overwhelm your design if you dont plan it in from the beginning.

In the first example the control arm can resist the torque generated at the axle center because it is mounted below & behind axle center. This means that the axle would have to move far upward in it's arc, outside of it's practical limits, for all the pivots to line up. It will always maintain torque control over the axle.

Hope that helps a little bit in your design.

-jb

Yeah, I'd love to see some drawing also. And thanks for the insight Vintage!
Billy

 

[JeepFreak21]

Yeah, I wish I'd read some good suspension books. I gleamed what I could from POR & my first setup was "trial & error".

Are you sure you want 12deg of pinion/caster change? Why? The pinion will be pointing away from the tcase at full droop making your driveline angles worse. Or am I missing it?

-jb

Hey, I was looking through the most recient JP Mag and noticed that they put out a book called "How to Modify you Jeep Suspension and Chassis for Off Road". Anybody read this? I'm thinking it may be helpful.
Billy

 

[JeepFreak21]

I keep looking at this picture of Matt's wishbone setup, and I can't figure out how his pinion doesn't end up pointing at the ground during droop. Anybody wanna help me understand this?

Thanks,
Billy

 

[vintagespeed]

I keep looking at this picture of Matt's wishbone setup, and I can't figure out how his pinion doesn't end up pointing at the ground during droop. Anybody wanna help me understand this?
Thanks,
Billy

Not to bag on this setup too much, but I doubt that proper geometry was a part of the equation.

Isn't that the 3link that folded during breaking?

-jb