questions about my model A rear spring setup

migth be stupid but whats your take on it? talking to a freind about this got me thinkin

i have a 29 coupe,8 inch rear,small block and auto.

well im running the stock 29 rear spring, with some leaves removed. im running shocks and radials. but it rides like a dump truck.my ride height is pretty good,but its stiff,the road jars you to bits.can i run a t spring to soften it? ive got about every other leave removed so i dont think i can remove more.buddy said maybe that made it ride stiffer??

front is possies reversed eye,it seems to be okay,i think just the rear is too hard.

 

try some softer shocks...the springs should be alright.

 

The spring is probably not the whole problem. The problem could be the way the rear wishbone was replaced and the type of ends on the the replacement rods that replaced the wishbone. The ends need to rotate if they are connected to the frame.

I am not an expert on suspensions. Post some pictures of your rear suspension and some experts will probably be able to tell you what needs to be changed.

 

my rear shocks are co-cals, they are not the problem i dont think.they arnt to stiff.

ihave troubles posting pics. i've seen others mount their wishbones similar, i have DOM tubing that are solid mounted to the rear end,and are on heims at the frame. its basically like stock split wishbone style. i dont really have room to hinge them at the axle and add a 3rd link.

 

The trick for posting pictures is to set the camera on the lowest or second lowest setting. I can post one picture at a time on dial up connection and it takes about 45 minutes. I do one picture at a time. This might help.

When a rear tire hits a bump, the rear end tries to rotate perpendicular to the frame. If you do not have enough travel for a little rotation in the rod ends the car will ride stiff. The wish bones on the original car attached to the drive line and the rear rear end was not restricted from rotation except for the springs and shocks.

 

does anyone know if the t spring is softer? i know the t spring does not go on under pressure like the a spring does. my spring perces are welded to my axle almost exact to stock,everyone knows the a spring has to be stretched to install,

i install my main then clamp the rest in but anyhow i know the t spring does not.im thinking that may lend it to be a tad softer ride. tho it may lower me a bit and im at a good heing right now. if i go lower i will be dead even with no rake.

 

I dont have a good answer for you, but I would unbolt your shocks and take a test drive. The reason I'm saying that is because my 28 tudor has a rear split hairpins,stock spring with ALL leaves in the pack, and in stock location. The *** end of my car is WAY too soft. and bottoms out like crazy on big pot holes in the road. Which i figure is because I have no shocks (yet). I suppose my original spring could be really weak though?

 

Ive drove without shocks before.it doesnt bottom out.it rides worse,it bounces more.sounds like your spring is WAYYY softer than mine

 

My 28 fenderless tudor has only five leaves and tele shocks . I have teflon liners between the leaves and teflon shackle bushes. The shocks are from a 60 compact sedan and seem to work pretty well for my application.

 

i dont have anything between my rear leaves.dunno how many i got tho.i thinl i took out 4 but not sure

 

Yep, we'll really need some pictures before we can really help you.

I've run these springs as well as 35-40s and they're nice and smooth, better than coil overs in my opinion.

 

It's scary just how similar our rides are dude! We all know how easy it is to over-spring the rear of an A, and mine is the same set up as yours. I insisted on not using coil overs-just my taste. But mine rides hard as well and I know it's partly because I use drag slicks. With out shocks it takes the bumps MUCH nicer, but mine are air shocks with no air lines hooked up.
If you stand on the rear frame above the spring and jump up and down does it have good travel? Is tire pressure excessive?

 

I have found that a stock "A" spring with about 4 or 5 leaves and the balance radiused at the edges, cleaned, painted, and tefloned gives a damn nice ride on a fenderless car. Most everybody wants to run 7 or 8 leaves and that is just too much for the weight of these cars. It was fine 80 years ago when the roads were dirt and ride quality wasn't a consideration, but these are different times.

 

I was running My A coupe (with coilovers) with 28 lbs air pressure in the rear tires. Dropped it to 22 and it rides much better. Might try a little more yet.
Ralph

 

got to know what spring you started with. There are several different springs for the A (truck, sedan, coupe..etc). If you take out 4 leaves form a truck or sedan spring then you still have a stiff spring for a fender less rod. But if you had a coupe/roadster spring and took 4 out it would make it ride a lot softer. Count your leaves and get back to us. ALSO, what angle are your shackles and are they bound up and hitting anything? Should be at a 45 deg when at rest.

 

"I have found that a stock "A" spring with about 4 or 5 leaves and the balance radiused at the edges, cleaned, painted, and tefloned gives a damn nice ride on a fenderless car. Most everybody wants to run 7 or 8 leaves and that is just too much for the weight of these cars. It was fine 80 years ago when the roads were dirt and ride quality wasn't a consideration, but these are different times."

Yup..5 leaves from a sedan spring should be plenty. After doing all Need Louvers said you should check the spring rate to see if you are in the ball park. For a soft ride you need to be around 100 lb. per inch on the rear with medium shocks.
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ill see how many are in it and get back to you.

 

do you guys take out a lot of the top small one?

 

For what it's worth.
On my 30 fenderless coupe, I used a t spring and took if I remember right, one of the upper shorter tighter springs and about the third longest out. I have no shocks out back yet. It is with the stock banjo rear end and unsplit stock bones.

I really enjoy how it rides. I cut the top of the crossmember out and raised it two inches. While this really doesn't affect the ride stiffness it did help bring the rear down.

Although not really comparing apples to apples, I bought a stock 29 Rpu and it rides significantly stiffer and kinda buck boardy compared to the A.

On the t spring I did take out a 3rd one initially and if I jumped up and down at the rear it would bottom out way to easy, I had to put that one back in.

A couple weeks ago I had two of ny boys in the cabin and two in the rumble seat and it bottomed out occasionally. But remember with channeling up the spring into the crossmember, my frame is much closer to the axle and I still don't have rear shocks.

Hope this helps

 

I've been reading this thread and wanting to give you some advice, but it is hard without seeing what you have there. If you can post some pictures it will help a lot.

For what it is worth, my 27 is on a Model A frame with a T rear spring, and I didn't remove all that many leaves as I recall. I think I have 7 or 8 in it now. The ride is very acceptable, not soft, not hard, just right.

What air pressure are you running ? I run 24 psi in the rear on bias plies, and I have noticed it gets harder if I go up to something like 28.

Don

 

im not running bias tires,i think im at 28 psi.cant go to low on radials

 

I've set up a number of A rear springs in different model Fords. Never have I randomly removed spring leaves from a laminated spring pack. When these are made they become a matched set, the leaves are different length because they are carrying weight & controlling rebound. If the spring is to hard or sits to high or low a competent spring works can reset the original pack to give you long term ride height & ride quality. As a foot note, I have a heavily chambered A spring pack in my 34 with 12 spring leaves and it drives **** hot!

 

Are the forward ends of the bars mounted on the frame rails, or do the converge towards the centerline of the car? If they're mounted on the frame rails you'll never get a decent ride. Mounting them that way prevents articulation of the rear end and puts all the components in a bind.

Bob

 

I'm wonderin this as well.
The bars can't run parallel, they have to end very close to each other just like henry made them.

 

I concur, this could very well be your problem. Henry designed it the way he did for a reason, it worked.

 

how can it bind? and they cant be unsplit.wont fit in my car as i have a auto,gull exaust,ext.they are mounted sligtly wider on the axle

 

when i jump on the rear it doesnt move much

how is the rear any different from split bones in the front?

 

The big difference between split wishbones on the front and rear is that most Ibeam front axles flex a bit to compensate for the loss of the factory designed Ford tringlular suspension system. The tubular rear axle doesn't fair as well in that department. It is going to resist twisting much like an anti roll bar would on a modern car. That said, it has been done 1.7 million times with varying degrees of success. It really shouldn't effect the straight up and down movement of the rear suspension unless something is really horribly wrong, just make things feel a bit more "harsh". It sounds to me like you have either a spring that's just flat too heavy, or maybe bound up at the shackles (they are at about 45 degrees at ride height, right?). To answer your earlier question about springs, yes, I usually use mostly the longer lower spring and pull the shorter springs at the down and cut them down to space up for ride height. Did you ever get the Bishop/Tardel book on building Ford hot rods? Mike did a good couple of paragraphs on this deal in there.

 

Because unless both left and right wheels rise and fall simultaneously (and that doesn't happen in the real world) The differing arcs prescribed by the radius rods try to twist the rear end housing. That ain't likley to happen, so everything in the suspension system wants to resist up and down movement. It's a well do***ented problem that's been discussed here until the cows came home.

Bob

 

Way different...there are many threads on here about this subject, but what it boils down to is this...
An I beam axle will twist allowing each end to move in a slightly different arc. A rear axle is rigid, which doesnt allow this type of movement. Without the twist, the suspension will bind...and parts will bend or break sooner or later.

Wow, I really need to learn how to type!