Rear Suspension Design Input Needed

I am currently runnign a single leaf with 6 inch blocks and bags above my axle in my 51 Chevy. It is a REALLY sketchy setup and needs to be changed.

I have a few ideas for a new rear suspension setup, and I really want to use the stock front leaf spring mount to mount arms too.

Ideally I would 2 link the car with the links only pivoting at the leaf sprng mount. But this would make the links pretty short, like 2 feet. I am concerned that this would cause problems with the pinion angle and perhaps would make the drive shaft go into the trans too far.

Here is a pic of some of the ideas I have. I want to keep it as simple as possible, but I need it to work. Cost is definitely a factor too. I will try to get some pics of my current setup uploaded this afternoon.



Any input is appreciated.

 

I'd go with a Truck Arm setup if it was mine.

 

I think the "watts link" style is going to change your pinion angle a LOT during travel. Watts links are for locating a rear side-to-side.

As the rear end travel the lower link will pull forward while the other link pulls back (or vice versa) causing (in my opinion) severe pinion angle changes.


I could be wrong though.


I do like the idea of the "truck arm" suspension.

By "single leaf", I am assuming you mean two parallel leafs (one on each end of the rear) as opposed to a true single leaf (transverse) like an original Model A uses. 6" blocks (HOLY CRAP) .... I have read that anything over 2" in not recommended (at this point you will hear from a lot of people stating that they run more than 2", but it IS what I read and I won't use any larger). I can only assume there must be tremendous "leverage" issues when running blocks that tall and then there's the issue with "scrub line" (meaning "if you get a flat tire does your leaf hit the ground and leave your wheel dangleing in the air).


I wonder if this would work ... buy a scrapper G-body and graft the entire rear frame section (with suspension and rearend) into your car, then sell off the rest of the carcass for scrap (I know of a 50's Buick with a Grand National type rear frame grafted in ... apparently it works great). This is an idea that I like but failing that I would lean towards a truck arm and crossmember style suspension (I am not a fan of parallel leafs when you need blocks that high to drop the car).

The problem I see with simply mounting a "two link" and using the front leaf mounts is when only one side of the suspension is compressed (turning a corner) the leaf spring is able to flex but a solid arm would not flex (and I don't expect your bushing would have enough flex in them either) which "might" result in failure down the road.

 

Id ditch the front leaf hangar, although it does seem like a good idea. That mount hangs under the frame, maybe it would make a nice drag block..if you want to cruise low.

 

doesn't that create clearance issues for the exhaust?

 

Hell, what doesn't?

The results are very impressive, though. This is Cinc's Chevy...

 

I agree with the truck arm setup, but it would make it really difficult to run the exhaust. Right now my exhaust is tucked up nicely between the frame rails.

I didnt think about the watts setup changing the pinion angle that much, but that does make sense.

 

Here are some pics of my current setup. It definitely needs to be changed.

 

Imho, I would IF I WAS TO DO THIS, use the single per side "bent" solid link design located off your existing front frame mounts and air-bags as springs and height adjusters. Then use an old-fashion link like a '50 Buick or so used to locate and control the rearend housings side to side sway that happen's when it move's up and down.

Use "Johnny-Joints" front and rear on the links so that the housing can "twist" going into and out of sloped driveways at an angle.

Can't get much simpler by me

Oh, and I am a fan of HTH's truck-arm kit!

pdq67

 

Man that's some scary looking shit. I sure hope you aren't actually out driving it like that!

 

went throught the same thing you are. (trying to decide) at the end of the day this is what was done, and how low it sits with 27" tall tires It is. braced and welded as well just dont have pictures finished. you get the idea

 

That's what I was thinking!! Holy crap!!!

 

I like it

 

No sh*t!! That set up is scary looking!! The leaf springs for one thing and some of the welds look questionable too.

 

If the frame is already boxed (if it isn't it should be) and you already have the air bags, the simplest solution is a triangulated four bar. Properly designed you don't need a separate lateral locating device. You could even cut a window in the frame kickup and run the front of the lower longitudinal bars inside the frame rails increasing the ground clearance. Left and right 3/4" rod ends jamb nutted into threaded DOM tubing would make compact, strong, safe, and reliable links (the four bars).

Also, moving the springing medium out (your air bags in this case) as close as possible or practical to the tire contact patch, inside the frame kickup is this case, will provide the most roll stability for any given spring rate and removes or reduces the need for a rear stabilizer bar. No panhard bar or watts link (separate lateral locating device) and no separate stabilizer bar means more room to snake the exhaust

I would also hope you intend to weld solid and/or box in the spring (air bag) mount on the axle.

 

Are you trying to keep the rear seat? I'd just copy a g-body. I'd get a donor, cut off the rear frame and fab up mounts to marry the chevy frame to new g-body spaced mounts.
Buick grand nationals handled pretty well.

Or, toss in a jag rear end. The cage is already built, just notch your frame high, run braces across and bolt her in.

 

Did you heat those springs to get that funky rounded "W" shape in them? I won't comment on the engineering, but I'd probably not drive that car very briskly.........

 

Trust me, I am NOT driving it like this. I set it up like this just to figure out where the rear end will end up, so I could order a driveshaft.

I like the idea of a 2 link with a panhard bar. It is the easiest for sure. I DEFINATLY want to keep the rear seat area intact. Thats one of the reasons I dont want a true triangulated 4 link. I dont think that I could get the upper links long enough.

 

Springs havent been heated at all. Thats what they look like when bent WAAAAY too far. HAHA, I wont drive it at all, thats why I started this thread.

 

Not helping here but that is some scary shit.

Go with the four link or the truck arm.

 

scary shit, 2 link with the short arms to the leaf spring mount won`t work, they are too short, been there, tried that, if you din`t have bags it would work, but the travel up and down does change the pinion angle a bunch, the best way i think is the truck arm style, nice long arms gives very good ride with the bags too, triagulated 4 link is an excellent choice, but tends to get into the back seat of these type cars, i have truck arms in my 52 buick, which is ver close to what you have and it works very well, and i built it from scratch, very cheaply......

 

The only opinion I have is I really don't like what you called " similar to watt's link". That can't be good for pinion angle

 

is that some kind of seat in your trunk?

 

2 link with a panhard or the 4 link bag on bar or bag on the axle is a good way and very safe if you take the time and set it up right IMO

 

if you are doing your own fab work, the truck arms are easy to make, 2x3 x 8th, rectangle, split down the middle short side, the weld back together in an i beam cinfiguration, only need to pivots, made mine for like 40 bucks, and don`t make them outta square or too thick of material, you want/ need some flex out of them......

 

Rod & Custom, Oct 2005 had an article on updating the rear of a 54 Chevy with the Walton Fabrication kit. It lowers the rear 5" using 2" blocks and still leaves 3" of space between the rear axle housing and the frame.

http://www.waltonfabrication.com/dh/0801.htm

 

I can get the trailing arms and the frame mounts from an old chevy truck for about $100. But I think it will be in the way of my exhaust.

I with the short 2 link would work.

 

ok, just tryin to help, i tried the short 2 link on a car of mine with bags, had to make the links twice as long after was said and done, they work now, but not anywhere near the leaf spring mounts....good luck..

 

I'm saying this respectfully, I dont see the dilema with the truck arms and your exhaust. The x-member you build for the arms, route the exhaust pipes through it. Then it looks like a 30 or 45 degree deal on each pipe just before the muffler and follow the angle of the truck arms back. Again I am not there, but it looks and sounds possible, you'll be safe and everyone will be happy. That would be awesome if you can pull it off. BDM

 

Actually I plotted the upper arm to the rear once before. Its not nearly as bad at changing the pinion angle as you think.
http://www.jalopyjournal.com/forum/showthread.php?t=203582&highlight=link+rear+facing&page=2

BTW the video in the thread stating it wont work is bullshit. If you scale that up to full size he is running thru 3 or 4 feet of travel. He also didnt play with any of the arcs to get a good medium.