[ccrodshop]

Does anybody have any info on setting up an I-beam front suspension.
I am familiar with the installation of the components, but I'm looking for numbers or guide lines for setting the caster of the front axle.
I am getting ready to build my frame and would like to know the angle for mounting the front spring mount and any other important info.
I do realize they sell cross members from other hotrod shops, but my pops owns/operates his own welding, fab, and machine shop business, so why buy when I can fabricate.

Thanks for any help you can give

Shannon
Cedar Creek Rodshop

P.S.
We have set up many dirt track, and drag cars and built chasis for both.
So, I do have knowledge of the more modern suspension systems.
It's these old rides that leave me questions.

[61bone]

You should set the caster at about 7 dg. Springs should mount at a 90 dg angle to the centerline of the bones at ride height. There is a ton of info here if you use the search.

[xntrik]

Originally Posted by 61bone

You should set the caster at about 7 dg. Springs should mount at a 90 dg angle to the centerline of the bones at ride height. There is a ton of info here if you use the search.

Just remember that caster is measured to the ground, not the frame. You must consider chassis rake.

Watch that bumpsteer.

[ccrodshop]

Thanks for the insight. I want to use a split drop axle.
So basically it will be an independant front suspension.
I'm still going to use the cross-leaf spring, regular 4" drop tube axle and radius rods. From what I read about this set up, it takes away some of that bump steer.
But, does this set up change the caster angle numbers or is it relative to most all other front end set ups?
Is there a way of determining the amount of sag of the spring set up to establish ride height?
I know that with most coil setups you can get this info from the manufacturer of the coil spring/shock assembly and without physically having the parts you can determine the ride height.

I plan on running an all aluminum buick V-8, 215 cu.in. motor. They were made in '63-'65 and came in the Skylarks and Specials. So, it will be lighter than a small iron block Chevy.

[KULTULZ]

Originally Posted by ccrodshop

I want to use a split drop axle. So basically it will be an independant front suspension.

I'm still going to use the cross-leaf spring, regular 4" drop tube axle and radius rods. From what I read about this set up, it takes away some of that bump steer.

I stumbled across this setup a few days ago and did not save it. Can you direct me to it? It also seems to me (IMO) that it would introduce bumpsteer, especially if using cross-steer. But if one was to mount a rack on the same bracket the axles hang from and both axle and tie rod swings in same plane, there would be no bump steer.

But, does this set up change the caster angle numbers or is it relative to most all other front end set ups? Is there a way of determining the amount of sag of the spring set up to establish ride height?

I know that with most coil setups you can get this info from the manufacturer of the coil spring/shock assembly and without physically having the parts you can determine the ride height.

I think you are going to have to determine the correct rate front spring (taking into account chassis/drivetrain and total vehicle weight. Then you are going to have to pre-assemble to determing actual trim height. Once that is determined, you can permantly located radius rod tabs to get the caster into the ball park. You would still have to shim the axle most likely, especially for road crown. Have you thought about a four-link?

[powerrodsmike]

Fatman makes that kit, it requires that you split the tie rod as well to eliminate bumpsteer.

http://www.fatmanfab.com/07page2.htm

Later, mikey

[61bone]

You might want to reconsider that split axle front. Body roll induces camber loss in cornering and also induces oversteer. In some cases it can be sudden and dramatic ala early Corvair. A book on chassis and suspension will tell you all about it.

[ccrodshop]

I never thought of that. Thanks for the insight.
It's fortunate for us young bucks to have the knowledge base of guys who've "been there" and "done that".
This website is an awesome tool.
I just hope that there are enough of us young bucks to soak up the knowledge to pass it on to younger generations.

[KULTULZ]

Originally Posted by 61bone

You might want to reconsider that split axle front. Body roll induces camber loss in cornering and also induces oversteer. In some cases it can be sudden and dramatic ala early Corvair. A book on chassis and suspension will tell you all about it.

Some type of sway bar is going to have to be employed (IMO) to prevent sudden IFS axle movement (prevent/slow body roll). Parallel springs would also make the design stiffer.

Even the early ECONOLINE front axle (soild) had a sway bar.

[xntrik]

Originally Posted by 61bone

You might want to reconsider that split axle front. Body roll induces camber loss in cornering and also induces oversteer. In some cases it can be sudden and dramatic ala early Corvair. A book on chassis and suspension will tell you all about it.

Actually with that short swing axle and a lot of axle drop (Corvair and VW had none) see picture..... the body roll increases the negative camber (top tips-in in relation to the chassis) for better footprint.

Look at where the axles pivot compared to the spindle centerline. The roll center is not on the spring end anymore but DOWN at the axle pivot.

A bouncing front end makes the camber look crazy..... Suprisingly they drive and ride pretty well, but I have only been in one. and I was impressed.

Quarter eliptics or coil overs should be OK.

[ccrodshop]

I was looking at the Fatman Fabrication split axle kit (the one powerrodsmike was talking of). If they are selling this kit, it must be safe or there would be one helluva liability case there. Not saying it's the best.
Have any of you guys driven/rode in a hotrod with this set up?
To me, it looks like the best of both worlds.
After this discussion, I might stick with the standard axle/spring set-up to get started. I can always install the IFS setup at a later date, after I get some miles on the car

[home brew]

Check out this page in cboy's journal on how he used an 81 front suspension in his rod:

http://www.hotrodders.com/forum/jour...ge=5&reverse=1

[327NUT]

Shannon....just to compare, Flaming River has just recently came out with a new split tube axel set up similar to Fatman except the axle does'nt split in the middle. Punch up www.Flamingriver.com and look under "new products" bottom of page. They call it "Dominator" (???)

[KULTULZ]

I am not sure I like the appearance of swing axles...

[powerrodsmike]

I remember seeing that last year sometime and thought it was lame.

I think if I wanted an F150 front end under my street rod, I'd do it like cboy's buddy charlie does. (go look in cboys journal that home brew put up the link to.)

Do you see the price of that dominator?

3550.00


I could buy 3 whole trucks for that.

Mikey