another truck armsuspension????

I am thinking of buying the steel to fab my rear suspension this weekend. I am going to use 2" X 3" box tubing. what is recommended for wall thickness? I searched the site and found suggestions anywhere from 1/16" up to 1/4".

 

I'd stick in the 3/16"-1/4" range for safety...

 

I was leaning towards 3/16 but just wanted to get some other opinions on it...thanks alot thats what I'll get then

 

Sounds good man, good luck...and don't forget all the geometry...

 

Oh yeah definatly I have it all drawn out and I've been taking measurments off of my frame for a better part of the last couple days figuring it all out...thanks again!

 

If I might make a few suggestions, sleeve a hole with DOM tubing at the front of each arm to press in bushings and use leaf spring mount pads with a plate welded on flat to it under the axle tab with 4 holes drilled in the plate, then weld two "wings" to the back of each tube with the same bolp pattern to mount the arms...

 

I was planning on the DOM in the front....at the rear I was think of what you sugested or (I've seen lots of pics with one Ubolt) I was thinking of drilling the arms in the center and welding a DOM sleeve where the U-Bolt passes through so I dont risk the arms crushing down any. But thinking the "dogbone" idea will be better with 2 Ubolts instead of I and welding in a stiffener to prevent the arm from crushing. Thanks agian for the suggestions and ideas...

 

According to a post made by zero to fear last year, Nascar uses 0.125" wall.

I'd be concerned about the lack of flex if you kept them as tubing... I've heard respectable people say it was ok, others that it needs some torsional twist.

 

So basically the arms he is talking about is 1/4" wall. After you weld the tubing back to back thats 1/4" and adding flat bar reinforcments it would be about 1/4" as well....right?

 

real "truck arms" are (actaully 2 "C" channels riveted together.. )

say no to square tube!




stock truck arms ARE NOT hard to come by..

if you look hard enough they should be cheaper than the steel your planning to buy..

look MORE..

 

What is the year range to look for and model?

 

The bushings will absorb torsional twist, stock truck arms work great...I'd stay away from u-bolts unless you have a pin or other locator so the truck arm and axle tube can't shift...

 

I know that the stock arms came on 1/2 an 3/4 ton Chevys from 60 to 72 and by special order on GMCs of the same years. The 3/4 ton arms have an extra 1/8" x 2 1/2" plate top and bottom for the last 2/3 or so of the arms. These plates make them quite a bit stiffer torsionally then the 1/2 ton versions. To work correctly the arms need to have the ability to twist and tubing will not work well for this application as it will place all of the twisting load on the rear end housing when one wheel is lifted and the other is not, as in turning into a driveway. If you have ever seen on you will know that they are very flexible, I thought that one of the two I acquired was bent, I held one end in a vice and with a 2' piece of pipe through the bushing hole I could twist the whole arm about an 1/8 of a turn either direction by hand, way flexible. I used stock arms in the rear of my '37 chevy truck and they work and handle very well. Good luck.

 

I use I beam to make my own truck style trailing arms. It allows twist and they do twist quite a bit.
Clark

 

I'm doing a custom truck arm suspension on a 1951 Ford F-1

 

I actually studied your pics in another thread...very impressive. I may change and go with I beams instead. I am going to go to the garage tommorrow and look everything over again and decide.

Hey Clark...how thick is the center web on the I beam? and also can the I beam stand up to a good amount of HP? That' s the reason I was looking at box tubing is the HP. Don't know actual HP of my set up but it's gonna be up there. Alos Clark...in the other thread you said you'd do a tech "how to" on this topic...looking forward to it...I kinda wish it wasn't being postponed for a month though...but still looking forward to it...

I want to use the truck arm suspension because it is simple, effective and can easily be adapted to air bags and can be custom built by myself fairly cheaply.

Thanks again everybody for the ideas and suggestions. Gives me something to think about and refigure a couple of things...my suspension may be postponed for a week or 2 ...

 

48 f1

on a chevy truck chassis.. with truck arms...

http://public.fotki.com/sawzallshop/sawzalls-rides-past/for_sale/

 

thanks sawzall...I just spent the last hour and half looking for pics of a 48-51 with truck arms....LOL...Thanks again!!

Those arms are original Chevy? Correct? The cross member appears to be as well....Thank for the ideas....I saved the pic link so I can refer back to it

 

HEY GREAT! you solved my problem, i didnt think about the arms being able to twist, but looking at one i see that they will. always wondered why GM used them that way! Will work on my Buick torq tube to open drive conversion.

 

Even the GM 3 and 4 link bars are designed to twist.

 

when i built the truck i didnt have a stock chassis at all (a friend and mentor gave me the cab and rear fenders)

knowing i wanted trailing arm rear suspension (and air ride) the choice of a 67 chevy truck chassis seemed logical.


as it turns out the wheel base was very close, and the local u pull it had the chassis sitting there bare...

the only thing about using the 67 chassis was that the front track width was too wide, hence the narrowed control arms

 

I think the web of the beams is about 3/16".

Jr's car (lime green coupe) had a strong 383 stroker and Jr doesn't have a light foot.

I recently bought a single pair of bushings that will work at the speed shop. They were from energy suspension and were for an 80's Mustang transmision mount. I guess they are for the crossmember that holds the tranny.

Here are some of the pics I started to take in the past. Hope it holds you over till I can do a tech. Take note of the gussets at the front of the I beam.
Clark

 

Clark, I'd like to see a tech on this...thanks!

 

Thanks alot Clark...I believe a I am going to use the I beam .....

 

Here is the part number for the ford mustang bushings Clark mentioned. Energy Suspension no. 4.1102g. It is called transmission crossmember to frame bushing. Summit and Jegs have em for 13.00 to 16.00 dollars. I ordered mine at advance auto about 20.00 dollars. Enough in one kit to do 2 truck arms You will also need a piece of 1.50 I.D. D.O.M. tubing. Thanks for the info Clark.

 

if square tube would work nascar would not go to the trouble to cut a square tube apart and make a back to back channel arm. neither would gm if if they could have got away with a square tube,

 

never looked at it that way...lol...thats very true.....

 

Not sure if it's too late for this, but I just put my hands on a pair of gen-u-wyne NASCAR trailing arms this weekend. Best I can tell it is 0.120" wall tubing as mentioned, but the top- and bottom plates that are welded on only cover the last 12" or so (toward the rear of the car). This would make it so that it's like an I-beam with 0.120 parallels and 0.240 vertical web.

 

Slide...do you think you might be able to get some pictures of the arms? I'd like to see some closeups of the bushing area and the rear bracing/axle housing joint.
If pics are impossible...how is the rear of the arm attached to the axle housing? One U-bolt like the trucks or are they using 2 U-bolts, almost like a leaf spring setup?
We're doing this setup on HAMBANDY's A and NASCAR spec would be hard to beat for durability.

 

Bill-- check back later tonight. I was already planning to do this!