Twin I-Beam? on a 1974 F-350 460 should I BUY?!
I fixed up my old broken computer and found the file I made when first learning about ford "TWIN I BEAMS". From re-reading the below information which was taken from all around the web, mostly from ford sites, I find myself with the prospect of wholly abandoning my quest for a '74 & older 2 wheel drive ford. (4x4 instead)
I have been told that twin I beams are "virtually indestructable" However nobody has said how they ride, esp. over time and when lowering or raising the vehicle. It seems that you would have your I beams bent 90 deg down in a right angle in order to raise a truck substantially:
__________twin I beam suspension____
Another one of Ford's "BETTER IDEAS"...You couldn't get twin I beam Ford truck to track straight if your life depended on it..I have always wondered now people drove the things..After overhauling the kingpins I would check at least the camber (which is unajustable except with a torch) and it would be pretty close..Setting the toe in negative helped some and making sure the rubber bushings were good..BUT!!! I never could keep a Ford truck "Between the guard rails "...I don't think they put much thought into the caster..(kingpin inclination)..For some reason I am building one now..For resale of course...Al..
Ford made the twin I-beam front end with the idea that it would never need to be aligned once set from the factory. Ford stopped making the twin I-beam because they could never get it into alignment. If you must change the front end, try looking into a front clip out of a newer truck. You can put upto a '91 front clip in a '73-91 GM as a direct bolt in, I'm not sure about Fords though. The other, cheaper, solution is to slow down... It will save you money on gas, tires, and engines.
. The redesigned 1997 trucks abandoned the twin I-beam front suspension in favor of the much easier to lower double A-arm setup.
As mentioned previously, lowering pre-'97 F-150s takes a bit of work. Ford's twin I-beam front suspension consists of two axle beams (like a traditional street rod I-beam axle cut in half) that pivot at opposite ends of the front crossmember. A coil spring is used on each I-beam. This system provides lots of suspension travel on stock two-wheel-drive and four-wheel-drive Ford pickups.
Suspension geometry problems arise when you're trying to lower I-beam Fords. Since the spindles don't pivot, lowering the truck via shorter coil springs pushes the top of the tires inward. This affects alignment and tire wear. Getting a top-notch alignment job is important when you're using shorter coil springs to drop a pre-'97 F-150 1 or 2 inches.
1997 Ford F-250 change completely new front suspension with upper and lower control arms. It replaces the ancient Twin I-Beam, With the new layout, ride is far better, handling is superior, steering feel is drastically improved and directional stability, such as when traveling at highway speeds in a severe crosswind (which we had an opportunity to experience), is immensely enhanced. We would expect that even tire wear, a Twin I-Beam weak point, would also be better.
Ford credits the 1965 introduction of its twin I-beam suspension as being a major factor behind the incredible success of the long-running F-series trucks. A truck that rides like a car and still works like a truck is how Ford ads touted the twin I-beam. It's true that Ford F-series trucks have smashed all sales records. In 1995, the F-series surpassed the Volkswagen Beetle as the world's bestselling vehicle nameplate. Ford's F-series trucks have been the bestselling vehicle in America for 16 consecutive years
please lay my fears to rest if you can do so? (or confirm the above?!)
<font size=-1>[ This Message was edited by: 67fastback on 2/6/04 10:50am ]</font>