Thread: ratrod suspension setup

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I am building a 37 Chev truck ratrod. I will be using a TCI hub to hub 4 " drop I beam axle setup for the front and a 8 " ford rear end out of a Maverick for the back. I will be building my own frame out of 2x3 steel. I don't want to channel the cab so the cab will still be worth something to restore someday if I want to , so I thought I'd set the frame at a 5 " ride height under the cab and kick the front and back end up as need be for suspension travel.
Has anyone been successful at getting the right look with a kick up or Z in the front ?

My second question is to do with the rear suspension. I wanted to go old school so I have a set of ladder bars and brackets from speedway to set my 40 Ford spring transverse either in front or behind the axle. Which is the best spot in front or behind ?

I would love to see some pics of how other people are doing it. The mags don't really show close ups and no one else is building this stuff where I live. Around here it's all about high dollar Chip Foose wanna be's. I'm attaching a pic of what I'm starting with, basically I will just be using the cab.

What a great condition cab!!!!! Spring behind on the rear axle would be my suggestion. With those huge fenders, a Z'd front will work fine. It would work best to have the wheels and tires you are going to run on hand, then set the kickup height on the Z section to establish your ride height, and of course do your frame construction on a very solid fixture. Good luck, should be a great project, keep us updated.

That's my favorite old Chevy cab. Why not use the front end, too? It's got character, and it looks to be in pretty good shape. "Z"ing the frame ahead of the firewall is hard to make look good, going straight up the firewall so it looks like it grew out of the 'wall might be best.
A tiny flatdeck and 15" dual wheels would be cool!
Alberta safety inspection might be a bitch, too.

Hi, I'm not running any hood or fenders and will probably use an extra 32 Ford grill shell for the front. I changed my mind on the rear end , I'm going to go for the ladder bars and coil over shocks. It's not as old school looking but should be a little easier for a first time builder. The big thing is that I don't want to have to channel the cab because it's in such good shape , so I have to get the look I want with playing with the frame. I thought about doing a suicide front axle instead of kicking up the frame in front. Can a suicide front axle work with a vega box and cross steering or would I have to go with a drag link and the tie rod out front ?

Coogan---The best way to achieve the look you want is with a z'frame. The front of the frame should have a vertical Z that runs straight up about 1/4" beyond the outside of the firewall, and the rear should have a vertical Z that runs straight up about 1/4" behind the cab.
The 4-link attachments for the rear axle also act as gusset plates for the rear Z, and you can run a suicide front end with a Vega cross steer set-up and 4 bars or hairpin radius rods.
If you don't channel the cab over the frame rails you will always see the frame rails below the underside of the truck, which looks kind of goofy.

Hi, thank for the info. I thought about the frame rail thing. The 37 Chev in it's natural state already has about a 4 inch channel in the back , and a 2 1/2 in channel in the front. Since I am using 2x3 by 3/16" thick frame rail I'm thinking the frame will only be seen at the very front of the cab.

The local hotrod shop said I should be doing my Z's at a 45 degree angle. Will the 90 degree angle you suggest be just as strong ?

If anyone has some pics of how a suicide axle with cross steer looks I would really appreciate seeing them. If I can suicide the axle then maybe I don't need to kick the frame up in the front much . 2 " maybe ?

Coogan---Hang in there for a while---I'm a design engineer with some time to kill this morning. I am doing up a solid model with my engineering software that I will post here in about 2 hours, that will answer a lot of your questions---I've been designing and building rods for 40 years.

Okay Coogan---Heres the deal---frame is built fron 4" x 2" x 3/16" wall mild steel rectangular tubing. Front gusset plates at the Z are burned from 3/8" mild steel plate. rear gussets/4-bar mounts are burned from 3/16" plate and set flush with outside of frame rails , thus leaving 1 1/2" between them for the 4-bar ends. The front cross-member is 2 1/2" outside diameter x 1/4" wall mild steel pipe and the 3 plates making up the suicide mount are burned from 3/8" mild steel plate. The height of the front end can be "tailered" by how high you make the suicide mount above the centerline of the pipe.
The rear crossmember can be either 3" outside diameter pipe with a 3/16" wall or another peice of the same rectangular tube that the frame is made from. The frame rails should not extend over the rear axle tubes, or it may limit your suspension travel and ride height---(you don't want the top of the axle tubes to hit the underside of the frame rails when you go over a bump.
This set up works best with coil-over shocks, or if you want to be economical like I am, weld coil cups to the rear crossmembers and matching coil cups to the rear axle housing at the 4-bar attachment brackets and run a set of conventional coil springs with bayonet type shock absorbers running up through the center of the springs. You will need to fab up a Panhard rod.
I have shown this thing with a total of 6" kick in the frame Z and with the truck body channeled 2 1/2"

Coogan--If you want to run a transverse rear spring, use the tubular rear crossmember and another suicide mount on the rear crossmember.---If you do that you won't need a Panhard rod, and you should use the 4-bar set up with the urethane bushings which will allow the flexing necessary. I would run the spring in front of the rear axle, which helps offset the rearend away from the rear crossmember to avoid any interferance between the pumpkin and the rear crossmember. Since you will be making the frame yourself the truck ride height can again be tailered by how high you make the rear suicide mount.

Thanks for all the info. I have to digest it. I really want to do this myself but feeling like I bit off more than I can chew at the moment.

I'm attaching links to pics I took today. The first two show my front end. I have a model A crossmember. Can I make it work with with regards to ride height with the model A crossmember ? I was thinking of maybe stretching the frame enough to put the grill shell behind the axle and bobbing the frame even with the front crossmember. If I go to the out front mount you suggested do I then have to go to a drag link and put the tie rod in front of the axle to clear ?

http://coogan.efirehose.net/37chev/axle1.jpg
http://coogan.efirehose.net/37chev/axle2.jpg

I am going with the hairpin radius rods on the front and similar on the rear. No 4 link but I will have coil over shocks in the rear.

Next two photos show the channel already in the cab ( stock ) The pic is from a spare cab and pick-up frame I have laying around. Do I need to go 2x4 or is 2x3 good enough for the frame?

http://coogan.efirehose.net/37chev/cab1.jpg
http://coogan.efirehose.net/37chev/cab2.jpg

The last photo is of my rear axle. It is a 8 inch Ford with a .300 gear. New wheel cylinders , drums , shoes and springs

http://coogan.efirehose.net/37chev/rearaxle1.jpg

So I have enough parts to get started but not sure really where to start. I have to build some sort of frame table as my shop floor is wood and uneven. Any suggestions on building something to build the frame on? It's a lot of questions but hopefully with enough advice I can make it all happen.

Some guys build a wooden frame table, or a steel one as long as u can have it level as wellas flat.

nice cab coogan, the older grain trucks are still around and some of them are in excellent shape. i like the 90 deg z idea better than the 45 as it is so much easier to get the angle . when i bult my bucket frame i put a 13 inch rear 90 degree kickup and fish plated the inside plate top to bottom with a plate where it could not be seen.
briansversion of the front frame bacing would look really good .
good luck with the project

Hey there. I dont have any advice, just want to say that I like the truck already. Should make for a good looking truck. Best of luck.

I've got my frame table built and starting to mock things up. I have the ride height a 5.5 inches under the cab and it looks like the driveshaft will enter the back of the cab. Is it normal when building a channeled frame that I have to cut a hole in the back of the cab and make a tunnel? Anyway I can get around it like a steady bearing? I can post more pics if it will help?

if the body goes down the drivehaft comes up as it is contstant. you may have to build a driveshaft hump of some kind to accomidate . make shure it is tall enought to accomidate the suspension travel.
i did not channel my t bucket body it is on top of the frame and i had to build a tunnel in the center for the driveshaft to get a lowride height with 34 inch tires .