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Four Bar or Hairpins?

6K views 13 replies 7 participants last post by  Centerline 
#1 ·
Hello,
Im going to start building a '33 five window and I have been wondering weather to go with hairpins or four bars up front and parallell or triangulated in back. The motor is about 450 horse hooked up to a m-21 with a quick change, the gears will be 3:55-1 and 4:11-1
Im trying to learn as much as I can before going to the frame builder,
Thanks in advance for any help,
 
#2 ·
Preference!! The hair pins have the old skool look the 4 bar the hot rod look. I think their may also be a small amount of caster adjustment with the 4 bar but i'm not sure. On the rear the triangulated 4 bar takes more work but works better and eliminates the need for a panhard bar. You should get HP Books "Street Rodders Chassis & Suspension" book. It will be the best $20 you'll ever spend. It covers everything you'll need to know on all your options, pros & cons and what to expect for cost of each option. They cover from a bare frame to a rolling chassis with the power train mounting basics too. It came out in 2000 so it's up to date and very well written. I love mine and use it regulary.
 
#4 ·
Go 4 bar

The 4 bar suspension system is just do much better than the hairpins it is unreal..If you look under a new dodge 4x4 it is suspended with a 4 bar..GM is using the 4 bar under the rear of the new suv's..I stick with the panhard bar myself..

OMT
 
#5 ·
One thing to consider in making your choice is that it is less desirable to run a tube axle with hairpins. You are better off to run an I-beam with hairpins. Four bars can use either tube or I-beam. The reason is that the tube type axle doesn't twist as readily when 1 wheel moves up over a bump so in effect you create a really stiff sway bar. It can create a problem in that your batwings, rod ends or clevises wear out faster because of the added stress. I have heard of tube type axles breaking at the weld also. Although many folks run these on their car, I don't think I would want to build a problem in if I could avoid it. Just my opinion.
 
#6 ·
powerrodsmike said:
One thing to consider in making your choice is that it is less desirable to run a tube axle with hairpins. You are better off to run an I-beam with hairpins. Four bars can use either tube or I-beam. The reason is that the tube type axle doesn't twist as readily when 1 wheel moves up over a bump so in effect you create a really stiff sway bar. It can create a problem in that your batwings, rod ends or clevises wear out faster because of the added stress. I have heard of tube type axles breaking at the weld also. Although many folks run these on their car, I don't think I would want to build a problem in if I could avoid it. Just my opinion.

My sentiments exactly. Except I would put it stronger..... Never run a tube axle with hairpins.
 
#8 ·
Centerline said:
My sentiments exactly. Except I would put it stronger..... Never run a tube axle with hairpins.

You guys are right with one exception.



I am running a tube axle with hairpins and it has the mobility of a 4 bar setup.
If you look closely, I have installed a swivel bearing in the center of this tube axle.
 
#9 ·
A swivel bearing in the middle of the axle. That sounds really neat. Is it like the fatman kit? I wish that the picture came through.
 
#10 ·
Please disregard my last post. Wow! I just found the picture. As well as the others you posted on that exphose website. That looks like a 32 cab and a 29 grill setting on a super trick tube frame and a what the heck is that in the back to push that truck around? That front axle setup is way cool. How'd you do it? Would it work on a magnum style axle? Inquireing minds want to know.
 
#11 ·
Ok so I spoke too soon again. go to walts homepage. Look at the 34 build pages. The answers are there. It won't be a wasted trip. Thanks walt.
 
#13 ·
Yeah..... I started the patent on it but it looks like it will cost a bit to finish. The bearing won't work with a magnum axle because of it's shape. It has a bow to it.

I'm running a mid engine 2.4 liter Porsche motor and 5 speed transaxle in the truck.



The truck is 48" high to the top of the roof. :mwink:

 
#14 ·
Now that's a great way to be different. No SBC there! :D

Not my particular thing but very nicely done.
 
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