I-beam vs IFS - pros/cons

I-beam vs IFS? It's a no-brainer on a hot rod.

 

Depends how much time you spend looking at your car.
And how much time you spend driving it, I suppose.

 

I'd say what do YOU want it to ride and handle like? Obviously on yours the cool look of a straight axle really won't be seen. Therefore go to the next requirement of how you want it to ride and handle. If you're wanting something more similar to what your more modern every day ride is, no doubt go IFS as the better handling characteristics and ride will be there. If not, stick with the straight axle. I myself will keep the straight axle in my '57 pickup cause that's what I'd prefer - a vehicle that rides like an older one as I think that's part of having one - kind of a whole theme thing. Another hang up of my own is seeing an IFS on a vehicle that originally didn't come with one - to me it just doesn't look right even though there are some very nice kits and installations out there. Plus it will be less expensive for me at this point.

 

Dang, yall sure do get heated over some front suspension! To me, as ignorant as it may seem, it is all greek! I am a bit of a dunce I suppose, I learn by doing.

Yeah, I bet between the drop axle and some spring work you could get 4" total. That is my plan on my front end.

If I am not mistaken, he is running paralell leaf springs, so the whole transverse conversation does not particularly apply here, but is a great conversation with a ton of great information.

What it boils down to is what you want your truck to ride like. I am partial to the beam axle because it was actually designed for my truck, and I dont have to shell out a ton of cash to get it...as opposed to a MII setup that was made for my truck. It gets spendy. Another great point was mentioned, that a part of owning a piece of history is enjoying how it was, not nessisarily making it all modern...ie S-10 frame swaps. If I wanted a cushy ride, I wouldn't be looking for a truck. Even the new trucks ride rough compared to cars...its all part of truck ownership. Even my OT truck rides like a truck...

 

I agree.

The restoration guys, with their wooden wheels and 20Hp, and the wind tearing at their hair at 40Mph, fighting to keep their car on the road at that frightening speed, deserve RESPECT !

But then a 200+ Mph salt car might be worthy of some modern coil over shocks and a bit of non standard heretical billet suspension modification, hehehe.

The eight second blown Hemi car with slicks is something else again..................

And then there is the chromed and polished multi award winning show car, that actually has no engine or gearbox internals, but the guy has spent a hundred grand plus, building it.

And then there is another guy with a Tudor with EFI, radials, auto trans, and air conditioning, and drives it every single day.

It is ALL HOT RODDING !!!!!!!!!!!!!!!!!

All of it.

 

I say go with whats under it! Cool has always been what I didn't have. Sorta got use to it. If I wanted mama to go with me everywhere I went I'd make it ride smooth as butter, if she stays home it alright to ride in a two horse wagon! I do love the look of a stright axel. It came factory in my 55 Chevy Panel truck and thats good enough for me.

 

Here is the '58 Chevy pickup I just finished for my dad. We flipped the axle on top of the leafs which lowered it 4 1/2". It has disc brakes and power steering. I set the toe at 1/16" out and gave it 4 degrees of caster. With new shocks and radial tires, it rides very very nice. I cannot imagine going through all the trouble of installing a clip or a MII on a truck like this after riding in this truck:

 

A sliding pillar suspension as designed by H.F.S. Morgan in 1910 and used on their sports cars through the 1960s gives you a beam axle with IFS.....

This excerpted from:

www.britishracecar.com/CarltonShriver-Morgan-44.htm




The stub axles slide up and down on vertical pillars. Coil springs are mounted concentric to the pillars, above and below the stub axles. Telescopic, hydraulic shock absorbers are mounted in front.



With sliding pillar suspensions there's no camber change as the body moves up and down on bumps, the suspension's roll center is at ground level, and wheel camber is equal to body roll. Binding in the suspension can be a problem on turns, plus bump and roll steer issues are inevitable.

Then again there is always the C4 suspension option - way superior to the Mustang II variants.
Don McNeil has been a hot rodder for ever and has developed a very nice conversion for early trucks.

www.flatout-engineering.com

 

Drive Em: Nice looking truck above! I've "self-aligned" a number of rod's front ends in the driveway. I'm puzzled that you find toe-OUT to be ideal, as I've used ~1/16th toe-IN consistently and never had a tire wear, or "hunting" or pulling road-ridge behavior.
And Ned, thanks for taking the time to explain in depth some of the handling & geometry elements. It's a big help in understanding what is taking place in a road-front end behavior game.

 

What a load of bullshit here!
Firstly the anti-roll bar is dampened via the shocks of the suspension [ unless in some fantasy world the mythical anti-roll bar isn't connected to the suspension at all ] ARB's also contribute to unsprung weight.

ARB's should never be that stiff that they "fight" the suspension on the opposite side. this is a common problem with cars that "pick-up" the inside wheel on corners

If your truck is a daily driver, go IFS there is no comparison.
Front half an F-body chassis would be my choice [ not mustang II ]
If you just want looks with a beam axle, join the '32 cult and build a hiboy

Most suspension [ 99+%] uses a medium that moves thru an arc [ either lateral or forward/aft ]
IRS A-arms move thru a lateral arc [ anti-dive features can change this a bit ] but doing so without changing the steering too much [ bad designs will have bump steer ]

A beam axle with parallel leaf springs can pose a problem, because when the springs compress they move forward or backward in an arc [ steering the beam ] as well as camber change from side to side.
Death Wobble is a problem with beam axles.

Yes you can set up a beam to ride nice [ usually spring choice ], or handle OKish in specialized circumstances but IRS is superior [ I've played with both in speedway and road racing ]

you can sell the beam axle on FleeBay for a Gasser

IRS without a doubt

 

Hammer, nail, head. If it was all about speed, handling, ride quality and comfort then the answer is a Lotus Exige, or a Range Rover Sport if you need a 4x4.

 

I have one of each, so I do have a little more than just an opinion. Remember that opinions are like a******s, nobody wants to see them or hear them!
My coupe has a dropped axle and reversed eye spring. It sits TOO low and I had to raise it back up with 1" spacer block. It has Vega steering, since to my knowledge no one makes R&P for a lowered '40 Ford.
The '41 truck has an ifs. It rides and handles like a car, has disc brakes and R&P steering. A lot more options for adjusting ride height.
The big difference I see is the rack and pinion steering available with the IFS. Other than that, I like to drive both cars equally. I drive one to chase parts for the other one!

 

Btt:

 

You can go split I-beams....for the best of BOTH worlds.

 

If I had it to do over again I would not put an IFS under my truck, sure the ride is nice and it has power steering, handles like a sports car, handling wise it's tight. The problem is that it weighs 3800 pounds, that's a bit heavy for an IFS according to some. The other problem is that the bushings within the upper and lower control arms have a life of 2 years and the hardware is all grade 5. Fact is that my truck is about as aerodynamic as a portolet, I should never really push it too fast, and being a panel it's top heavy so am I really going to be able to keep it under control power sliding it, no. If I had the whole thing to do over again I would have put something stronger and more massive under it that could hold the weight without any worry, at the time of purchase I was confident that is what I had, and then gravity and metal fatigue and all the powers of the universe take a toll and now, not so much.
Take a long hard look at front suspensions at the next show you are at, guys who know what they are looking at have to break out in cold sweats, it's like a horror story how little holds some of these cars off the ground. Take a long and serious look at El Polackos link to his shop, he has a Dakota chassis on there, compare it to car type ones, learn to look at the details and you will see something that will be quite capable of holding up a truck. Also take note of the different metals that these suspension components can be made of, steel is not all created equal, there is quite a lot to educate yourself about with this purchase you are about to make, I suggest being patient and learning as much as possible about all of the aspects concerned with the purchase, it's no fun pulling the whole front end off every 2 years, as a matter of fact it's absolute bull shit, and they are a custom size bushings and I get meat plowed on the price of them. I would today use a modified Dakota front suspension as shown by El Polacko. As a matter of fact I may just gut out the current IFS I have in there and replace it with something he recommends.

 

Hmmm... that's what a new 4 door Honda Accord weighs. That's not heavy. So it depends on the IFS.

Personally I think straight axles can ride pretty damn good if set up right. And IFS can be pretty bad if done poorly.

 

Unless you use a Mustang II, a vehicle that weighed between 2650 and 2850 in it's various forms, plus passengers.

 

Kingpin bushings are the biggest draw back; they wear out much faster than ball joints and this could be aggravated with the use of disc brakes.

 

all comfort has been discarded for style!!!!!

 

<TABLE border=0 cellSpacing=0 cellPadding=6 width="100%"><TBODY><TR><TD style="BORDER-BOTTOM: 1px inset; BORDER-LEFT: 1px inset; BORDER-TOP: 1px inset; BORDER-RIGHT: 1px inset" class=alt2>If you've ever driven an I beam suspension down a washboard road you'll know why IFS is much better. Forget the I beam unless you enjoy the cool factor and the crappy ride on crummy roads. </TD></TR></TBODY></TABLE>

I own Ibeam cars and IFS cars.

And I live down a dirt road.

But you go right ahead and believe that nonsense....

 

I'm putting an IFS in my '48 4100 Chevy. Easier to adjust for spring rate, ride height and parts availability (assuming you use a commonly available clip.) It takes a little more engineering, but you seem to have the fab skills.

 

Converting an old truck to IFS makes it a Street Rod or Kustom candidate. That's okay, just don't imagine that it's a traditional 'rod after that conversion.

 

Here's a "traditional" modification courtesy of the H.A.M.B

http://www.jalopyjournal.com/forum/showthread.php?t=148978

 

could you please post some pics of the front axle setup ? thanks

leonard

 

handling and tire wear go to ifs for sure