Steve of Hot Rods to Hell has been building "Truck Arm" suspensions for over 15years. Has had some of his suspension setups on a few very quick Silver States Classic cars and some really nice Chevy's. http://www.hotrodstohell.net/truckarm/truckarm_index.htm He moved from Oxnard to Anderson, CA. Stop by his shop if you get a chance.
1 1/2 x 3 x3/16 would work. 1/8 wall will work too if you don't hang bags or spring mount off the side of the arm.
Nascar uses them because they have to not because they are the best suspension. There is a difference from a limited travel race suspension VS a street car. They are available from just about every race car wharehouse for under $100 with the bushings. They also sell the front crossmember again with the proper angles already welded and worked out for dirt cheap. The arms do flex and that is part of their function. With the HP levels run today in Nascar don't you think they would box them rather than keep the same 30 year old design? The front bushings prevent bind in the suspension movement. Hot Rod to Hell modifies the mounting points of the panhard bar which is a difference from a stock set up. Mount your shocks and springs as vertical and far out as possible. They do work and provide a nice soft ride with predictable handling.
I have been running the 49 Olds. rear set up with a transverse spring on my 37 Ford cp. for 21 years . It hooks up and handles great, as an open rear but both tires smoke and lay down equal rubber tracks.
All things considered - it's a pretty sweet set up for a Hot Rod. In my op - a much better choice than 98% of the ( fits all ) Magazine add crap. But if you do it, take a real good look at the set ups on Cupper Race Cars & trucks. - mount the panhard bar as low as you can - behind the housing is best, and use a anti roll bar set up.
Got any closer-up photos of the front crossmember? This looks VERY close to what I've started for my 52 Fleetline.
here it is . these brackets are from chevy truck too. I got the truck arms from junk yard for $20 each .
Thank you chopstix... That pic is exactly what I have been looking for. I'm using this in my '51 sedan.
Just wondering, if the truck arm rear suspension was such a great design, why did Chevy stop using it in '73? thnx, jack vines
Cost, as they were building trucks both ways (leaf and trailing arm). When the gas crunch hit, it couldn't have helped any either (as at that point everyone was looking to 'tighten their belt'). I expect they went with leaf after that because the trailing arm was a Chevy 'option' (as from what I read GMC never offered it, wouldn't surprise me to see one that way though). That and unless I misunderstand, it was only available on the 1/2 ton trucks (so at that point you have tooling, parts and personnel that are working on a very minor part of your production total, that can be eliminated at the stroke of a pen, if you look at it like you're GM).
Around here few people thought the coil springs on the truck arm set-up was HD enough. Leaf springs can always be made stiffer. I worked at Chevy dealers in 67/68 and, if you wanted a HD rear suspension on your C10, you ordered leaf springs. That being said it's a great suspension for a hot rod...
I just sold a '69 GMC 1/2 ton with the coil spring suspension, and I have seen 3/4 ton Chevys with the same suspension.
because it wasn't the "best" setup for a truck to haul heavy loads. which has little to do with why it works quite well under hot rods and kustoms.
Thanks for the replies. Just trying to follow a thought. GM decided it wasn't the best for light trucks. Has any manufacturer (other than NASCAR) since '72, chosen anything similar to the truck arm for an OEM suspension? thnx, jack vines
What thought are you trying to follow? Truck arms (triangulated 2 link with Panhard) are a continuation of the thought process that was the torque tube design...just converted over to use an open driveline. It's simple and strong. Offers good handling and low roll resistance in normal usage. Modern vehicles tend towards more of a tuned suspension where body roll influences rear axle positioning to assist cornering. Also crash testing might be a bit easier to pass by having lighter suspension arms closer to the outside and easier to deform. Thats a part of the reason most OEMs are using independant suspensions. It's not just about the ride! Some modernish vehicles used the 2 link beyond 72...but they have/had the added complication of outboard mounting that was parallel to the frame rails, so must have some form of flexibility at both ends of each arm to allow for normal suspension articulation without breaking parts. Nothing wrong with truck arms or other form of triangulated 2 link for our use!
Has any OEM since the mid-1950's used the straight front axle with wishbones? You must understand that the OEM's do things for many reasons, but in a family car, performance and good function are very low on the list of design objectives. I have a buddy that works for GM in the advanced R&D department. They will totally redesign things (and not for the better sometimes) in order to save $0.05 per part in the assembly, or to save half a pound overall. In a hotrod, all we care about is that it performs as we wish it to, and is strong enough to do so for some time. Weight is of little concert. Ten dollars per assembly cost wise makes very little difference. Ease of manufacture over hundreds of thousands of parts doesn't even enter into it for us. It's apples and rutabagas really, the circumstances, and therefore the design requirements are entirely different between OEM's and hotrodders.
As my name states, I have a 71 Suburban. It is running the trailing arm suspension also. I had a built up 468BBC in it and NEVER had any problems with wheel hop.(pulled motor to swap in a late model MPFI SBC) The ride is excellent on it and the handling with the addition of a 4th gen F body rear sway bar is incredible... Now, there IS a difference in the trailing arms between a 1/2 ton and a 3/4 ton truck. The 3/4 tons have some plates welded to them to stiffen them up. The plates that the truck suppliers sell to reinforce the trailing arms are basically the same thing that GM did to the 3/4 ton arms. Does it make a difference? Some guys say yes... Having had both 1/2 & 3/4 ton suburbans, I can't say I've noticed a difference. A friend of mine has a 67' C10 shortbed running a 496 BBC in it, TH400 with a 3200 stall and transbrake and a 9" bronco rear hung on the stock 1/2 ton trailing arms. Runs a 32x14x15 mickey on the back and I've seen that truck pull the wheels over 12" off the ground. Never broke anything outback(did bend a control arm). Finally, about the whole "flexy truck" thing... Yes, the C10's flex. So do the F1's and countless other old cars with a stock chassis. Ever watch some of the old movies with the T's going down the mud roads? Take a look at one sometime and watch how they twist. That is how they were designed and built. Ummmm, correct me if I'm wrong but I think that maybe, possibly, could be why you would box a frame? Hmmm... Guess if you can do it to a T, A or what have you, it would work the same on a flexy C10.
Kreepa do you have any more pictures of your A (that show more of your suspension install)? Drive Em, yes, not surprised about the GMC with that setup (as you could order jsut about anything, any way you wanted it back then, if you or your salesman knew how). 3/4 ton stock with that? First I've heard of it (not that surprised there either though). Don't some over the road trucks use a two link style setup with air bags instead of coils? I want to say Peterbuilt or Freightliner, but I'm not sure (I don't have one of either).
do you see something wrong with this setup, are you looking for newer donors or are we playing 20 questions?
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