Hot Rods Rear suspension ?

I am building Model A hot rod. Boxed A frame,no hood/fenders,327/350,s10 rear and dropped axle with hair pins. Time to start rear suspension. Will probably be coilovers but might go with coil springs and would like some input/experience on ladder bar vs 4 bar vs rear hairpins for safe street ride and handling. Frame will be z'ed in rear for ride height Thanks Bill

 

i like Pete & Jakes ladder bars angled in towards the center. take a look at what they do and do the same

 

Nothing uglier than a fenderless A (on A chassis) with those hideous rear four bars hanging down, looks like, well, s#it!

 

A lot depends on what you plan to do with it.

You want just a street cruiser, something that handles the curves or maybe some street/drag racing on occasion?

 

Just street use. No racing. Just looking for good road manners.

 

Triangulated 4 bar with the top bars mounted on the tubes, not the center section. Only see the 2 lower bars, ride nice. Easy to do with coilovers. Lots of kits out there. Speedway, Pete and Jake (pictures of my 32 P&J chassis). Let the arguing begin.
SPark

 

I like the benefits and ride of the triangulated 4 link myself. Kind of the best all around suspension out there.

And if you run adjustable ends on both ends of the bars they are easily adjustable for pinion angle, load etc.

 

About the simplest, and most traditional, you could do is hairpins. The problem is they don't allow for articulation of the rear axle, or independent movement of the axle ends. So they don't offer a very supple ride over rough roads. But they do provide for very flat cornering. It'll corner like a slot car. With a light weight, short wheel base Model A with hairpin rear suspension, you'll hang with just about anything down a tight twisty road. If you've got any canyon roads around you, you'll enjoy it. 4 bar rear suspension will absolutely give you the best ride quality, but they are not traditional, if that's important to you. And as Denny posted above, they aren't attractive. Ladder bar suspension is kind of in between those two, with a little more articulation than hairpins, but not equal to 4 bar, but they really work well under highly stressed drag racing conditions.

 

So, do you have any photos showing installation with an A frame, which the OP is using?

 

I do not but I have seen them. I used my chassis as an example of mounting the upper bars on the axle tube instead of the center section. It would all depend on ride height he as in mind.

Look on Pete and Jake's web site, they have them.
https://www.peteandjakes.com/parts/rear-triangulated-4-bar-1928-31-chrome/

https://www.yumpu.com/en/document/view/3609884/open-full-pdf-pete-and-jakes-hot-rod-parts/9

So does Speedway.
https://www.speedwaymotors.com/Tria...sion-Assembly-Kit-for-Model-A-Frame,8382.html

SPark

 

Here's one of the setups that I built. These are P&J bars, shortened.

 

The reason I asked is that I believe the narrower A frame adds some complications to getting the upper arms installed with the correct angle and length, and would like to see an installation.

note that Speedway kit seems to be only for their A frame maybe? Though maybe it could be used on an OG frame with modifications.

 

I haven't worked on the A chassis but if you aren't averse to cutting the trunk/floorpan, the options are greatly openened up.

 

I have read about the limited articulation on ladder bar and hairpin set ups. Like pics of LM14's triangulated 4bar setup. I know it would ride good but how about you guys running ladder bars/hairpins on the street? How do you like the ride and handling of them? Thanks Bill

 

I like Gimpy's work...depends in this case, if side loads (cornering) and 'shackle-shift' harm the rear tube mts.

 

Some Model A triangulated rear four bars :

 

Pete & Jake's ladder bar setup is very good. Triangulated four bar will not handle as much power, ask me how I know. I would be more concerned about the s10 rear end. Everything is highly visible on the rear of a model A, and quite frankly the sight of the s10 rear will make you vurp. Maybe look for an 8" or 9" ford with a smooth back housing.

Sent from my SAMSUNG-SGH-I747 using The H.A.M.B. mobile app

 

My A pickup uses hairpin rear suspension, and the ride and handling is pretty much like I described above. The ride quality is taut, but not objectionable for a sporting vehicle. But you do feel every imperfection on the road. And it corners like it's on rails, with very predictable handling. It stays flat in hard corners and goes where you point it. You can feel exactly what the tires are doing, and you know when you're at the limits. Slides are predictable and controllable. Like I posted above, on tight and twisty pavement it runs real good, as long as the surface is in decent shape. It's kind of a hooligan car, it encourages you to drive it hard, and it rewards aggressiveness. But it's not a soft and supple ride. If that's what you want, look elsewhere.

 

Great info and pics you guys have responded with! Another question came to me that I should have also asked. About what spring rate you running on rear coil overs or coil springs. Body is going to be finished as a 28/29 RPU for weight guesstimation.

 

It hasn't been very long that I just bought new coil overs, but I don't recall for 100% sure, but I believe I ended up with 300 lbs/in, on my 30 A closed cab pickup. This was the standard shock they stock at the local speed shop for early Ford hot rods. On my car, with 980#'s on the rear axle and 2160#'s total wet weight, this is a little on the taut side. I currently have the preload backed almost all the way off. 250 lbs/in would probably give a little softer ride, and the spring preload adjustment would allow you to gain back some clearance if there was too much sag. The angle of the shock also makes a difference, mine are mounted at about 30 degrees in at the top. If mounted straight you would need a lot less spring rate.

Here's a little info on proper mounting which may be helpful: http://aldanamerican.com/suspension-installation-guides/

I have these guys shocks, very nice components: http://aldanamerican.com/coilover-kits/