Why is twin I-beam the worst of independent suspensions?

[Chapap]

I know there's the steering alignment issue throuought travel and the camber geometry issue. Is that it? TIB suspension was a negative when I was comparing old rams vs f-###. The only good things I've read about it were along the lines of "at least it's not a solid axle." It doesn't seem like the previously mentioned issues would contribute to the most-prone-to-roll-over award that the explorer got one year. The only difference (except for previously mentioned) between TIB and double wishbone (or whatever is standard now) is the length of the arms. It seems like longer would be better even.

 

[Roert42]

Some people would argue that Twin I beam suspension is the best IFS out there. Due to it's rock solid reliability and generally robust design.

The only real downfall that I can think of would be the fact that it's an older design, that's not used much anymore and not many people know how to properly align a TIB suspension.

I had a TIB with coil springs on an F-150 for years and did not have any complaints.

They did sell them for a few years with leaf springs, and I heard bad things about that because the movement of the I beams caused the leaf springs to twist.

 

[ericbphoto]

I never heard or thought that it was the worst out there or even inherently bad. I think it is greatly misunderstood. TIB/TTB gives a softer ride than solid axle because it is a type of independent suspension. Because of the longer pivot arms (longer than normal independent designs) it gives greater and easier articulation. The only time camber is a significant issue is when the suspension is improperly lifted or lowered without regard to it’s geometry. But improper lift or lowering of any type of suspension will end up causing some kind of problem. In fact, I believe a very similar setup is sometimes used in desert racing in order to achieve great articulation.

 

[superj]

I thought explorers were rolling over because of the firestone tires

 

[Blmpkn]

I think it's sweet much easier to meaningfully increase the total travel with beams rather than sla.

 

[fastpakr]

I thought explorers were rolling over because of the firestone tires

Sort of... Lots of contributing factors there. Ford spec'd a much lower pressure on the Explorer (26psi) which exacerbated the problem. Blame everywhere.

 

[Chapap]

The only time camber is a significant issue is when the suspension is improperly lifted or lowered without regard to it’s geometry.

I meant that camber changes throughout wheel travel.

From personal experience, I couldn't give an opinion... TIB might be bouncier. For some reason I thought the consensus was that TIB was generally inferior to wishbone.

 

[fastpakr]

For some reason I thought the consensus was that TIB was generally inferior to wishbone.

Everything is inferior to wishbone.

 

[Blmpkn]

Everything is inferior to wishbone.
View attachment 83634

I can't believe I forgot about wishbone.. yeesh. Sorry lil buddy. Bringin' meh baaaack

 

[rusty ol ranger]

Run an I beam truck and an SLA/Torsion/macphearson truck down a rutted dirt road at 50 mph for 10 miles and see which one comes back intact.

Simple stupid durabilty is why in my opinion they cannot be beat except by a king pin solid axle.

 

[rusty ol ranger]

I thought explorers were rolling over because of the firestone tires

underinflated tires and idiot 80mph drivers who expected a slightly longer bronco 2 to handle like their previous taurus

 

[alwaysFlOoReD]

TTB/TIB are great for long travel desert runner and baja style trucks. SLA is better for cornering. Had I known this when I built my race truck I would have looked for a SLA truck. The TTB in s-corners will jack up and have a greater tendency to roll. Look at my avatar pic, that's what happened the first time I was out racing in an s-turn.

I wouldnt say it's the worst. Just need to know the pros and cons.

 

[Chapap]

TTB/TIB are great for long travel desert runner and baja style trucks. SLA is better for cornering. Had I known this when I built my race truck I would have looked for a SLA truck. The TTB in s-corners will jack up and have a greater tendency to roll. Look at my avatar pic, that's what happened the first time I was out racing in an s-turn.

I wouldnt say it's the worst. Just need to know the pros and cons.

How about for strictly on pavement? I get what yall are saying about TTB on dirt. I usually crawl on bad dirt roads, but the ranger seems to beg for more speed the worse the road is.

 

[alwaysFlOoReD]

Strictly pavement SLA would be my choice if racing. TTB/TIB would be fine for a daily driver, and has been for decades.

 

[ericbphoto]

How about for strictly on pavement? I get what yall are saying about TTB on dirt. I usually crawl on bad dirt roads, but the ranger seems to beg for more speed the worse the road is.

What @alwaysFlOoReD said would hold true for high speed road driving, such as twisty mountain roads or rally racing. But you would want to keep the anti-sway bar in place or even upgrade it. If rally racing, you would probably be lowering the truck and modifying the suspension and the characteristics of TIB could be accounted for. I drive mine on twisty mountain roads often and mine has a 6” lift and NO anti-sway bars. I just keep that in mind and drive safely. I’ve never had an issue.