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:
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__________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
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please lay my fears to rest if you can do so? (or confirm the above?!)
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<font size=-1>[ This Message was edited by: 67fastback on 2/6/04 10:50am ]</font>

Hey, relax. You think Ford sold however many million trucks with the Twin I-Beam and then no one could ever get an alignment done on them ever again? Hell no!
Yes its more difficult to align a Twin I-Beam than a more typical A-Frame suspension, but a good shop can do it.
Yes the Twin I-Beam is known for chewing up tires a little more quickly. Its also known as one hell of tough, durable, reliable front end.
Yes, the Twin I-Beam is harder to lower than a Chevy front end. Are you gonna lower it? No, then who gives a @&amp;*% if its harder to lower? If you're gonna lower it you've got options, either a front end swap or an aftermarket lowered I-Beam.
You're looking at a 68-74 truck, its gonna have the I-Beams you can align by bending them. No big deal. Yeah the trained Monkey at Midas isn't going to be able to do it, but a good shop, especially a shop that does heavier trucks, its a no-brainer for them. Yeah, the bending process is a little bit of an art, but its not rocket science and like I said there are millions of these trucks on the road, somebody must know how to align them? Do you see 68-74 Ford trucks wandering all over the $&amp;#(ing road like the driver is three sheets to the wind? Nah, so they must have a half decent alignment on them.
A 68-74 2wd Ford pickup would make a tough, reliable tow vehicle. In fact I'd rather have a Ford from that era than a Chevy, because of the leafs in the rear of the Ford and the more durable Ford front end.
[addsig]

I don't think I'd worry about it either. I've had loads of 67-79 Ford trucks and never had a problem getting aligned. Ever. Then again I never drop them to a ground (if you want a lowrider get a car).

Check ya PM box... [img]/phpBB/images/smiles/icon_smile.gif[/img]

I have a 71 F100 that has been in the family since new. I think the twin I-beams are about the toughest front end out there. I've had mine aligned professionally once. The caster and camber have stayed the same since then.
I was just involved in a wreck where a lady ran a red light and hit me on the left front fender, wheel and door. I replaced the steering box just for safety reasons then I had to replace the left I beam. If you layed it flat on the table you would have about 2" of clearance between the table. That I-beam took the blunt force of her 2003 Explorer. It did bend but I think it absorbed enough of the force to lessen the3 damage to the rest of the truck. The frame appears straight. Another cool thing is after I replaced the I-beam I placed 2 straight edges against the wheels and aligned the front end with a tape measure. Rides and drives just like it always did. The only weak link in the I-beam is the king pin. One way to solve that problem is to change out the nylon bushings for the brass bushing. It requires reaming them to fit but they'll last a long time
Clint
[addsig]

Have a 78 F-150 thats been in family since new, 265 thousand miles most of it's life spent hauling scrap iron with the suspension on the stops on gravel roads. Tracks down the hyway excellent, last time it was lined up was the assembly plant in 1978. Only thing ever done other than a wheel bearing is grease every 3 thousand miles! Wheel bearing failure from driving through foot and half of water during flash flood and my fault for not checking them.

T T B ! ! !
OK, I own a '72 F-250 4x2. Twin I-beam.
How do I make a stock-stock 4x2 to 4x4 conversion?
I want to keep the geometery of the Twin I-Beam.
While having the capability of a 4x4.
So TTB from a later year seems to be the best option.
This is not for mudding, or rock crawling. I just want it for driving in winter, and getting my butt out-of-trouble.
What do I need to get in order to make this change?
Any help would be great! [img]/phpBB/images/smiles/icon_bow.gif[/img]

P.S. My current configuration is:
7,500 GVW, 3,150 Front GAWR, 5,140 Rear GAWR,
351W ('out of '79 T-Bird)
C-6, Dana 60 w/4.10 gearset,
8 lug split rims, Hey, don't dis my rims. [img]/phpBB/images/smiles/icon_smile.gif[/img]



[img]/phpBB/images/smiles/icon_bow.gif[/img][img]/phpBB/images/smiles/icon_bow.gif[/img]
[addsig]

It can be done, however your looking at a LOT of fabrication. You'd almost have to replace the front section of frame with the later stuff. I looked around at that exact swap, but decided it wasnt worth it and am now simply building an 81.
[addsig]

All I know is that I've had an '86 F-150 4x4 and a '75 F-250 4x4 and I wouldnt take ten IFS suspensions for one straight axle!

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On 2004-05-11 18:07, BigRed250 wrote:
All I know is that I've had an '86 F-150 4x4 and a '75 F-250 4x4 and I wouldnt take ten IFS suspensions for one straight axle!
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AMEN!