I was reading Super Joe's signiture, and it said that his 85"4Runner had rear IFS.
Is it possible to have front and rear independatnt suspension? and what do you think that would be like.

It would be kinda cool to have the Total Chaos Caddy suspension on front and rear.

Kent

 

yes its possible. Most of the cute-utes have irs...so do many many cars

the reason why ifs is often said it sucks is because there are more parts to break than on a solid axle..and dont forget that you have CV's with any independant setup..which means angles can get extreme and cause problems with ehavy lifting

 

you could...but why would you want to? theres a reason theres no crvs, rav-4s, and ridgelines on any trails

 

i dont think the point of livelarg's post is to debate that vehicle do or dont have independent rear suspension.

i think his post is to pretty much see why superjoe's signature says "Rear IFS"

Rear IFS kinda cancels each otehr out as IFS refers to Independent Front Suspension. To hace independent suspension in the rear would be IRS (Independent Rear Suspension), not Rear IFS

there is no such thing as rear ifs

 

May I hi-jack just a tiny little bit? Did I hear a no? No? Ok. Thanks

I was just wondering if any of you guys could clarify the difference between the IFS/IRS type vs. the SAS. I am pretty sure I know what it is, I just wanna clarify.

IFS/IRS = Only the 'ends' of the suspension move up and down.
SAS = The whole normal shocks+springs deal, usually found on the rear axle.

I hardly know what I said there, so sorry if I sound like a noob, help a guy out . Last thing: How does power get transferred to the wheels from the diff on an IFS/IRS?

Thanks a bunch,
Marko

 

IFS/IRS has a center differential coupled to the drive axles by a CV joint and no axle tubes, meaning an open axleshaft.. they are allowed to move independently of each other... both side can be fully compressed at the same time, one side doesnt effect what the otehr side is doing

in an SA situation the axle is solid, the differential, housing, and axleshafts are all contained in one protected unit to the wheels, if one side were to go up, the otehr side would get pushed down, this doesnt happen in an independent setup

 

Independent gives a better ride, especially on the highway, but as macrunner said, independent suspension is more prone to breakage with heavy OR use. Solid axles are more articulate, are better for generally harsh terrain, and work wonders with just a locker for rock crawling. In fact, Marco, if you hav a spare 2K and don't now what to do with it, just go ahead and SAS your Runner!! Haha... Just joshin' ya man.

 

IFS - Independent Front Suspension. Typically the differential is mounted to the frame and control arms pivot independently on each side, for 4wd will have a pair short driveshafts coming off the diff - one to each wheel hub, and CV joints or similar (4 sets!) to allow them to flex. Complex, lotsa moving parts, not particularly strong or durable and requires a bit of maintenance and adjustment, provides smooth ride on the highway. Limited for offroad flex, difficult and expensive to build up for extreme offroad use. Look under your 4Runner and see how it works (unless you only have 2wd, in which case fuggidaboudit...) edit: Here's a pic of IFS attached below -


SAS, means Solid Axle Swap - removing the IFS components and installing a live-axle setup instead. The reear axle in your 4Runner is a live axle.
Live axle setups can have leaf springs or coild springs. Simple, low tech, low maintenance, can be bulletproof, can be easily built to allow insane flex. Here's a rig that has had a SAS done:

 

Military HUMV's have IRS.

 

Yep, and they are heavy, very expensive, and require a lot of maintenance.

Story about a Humvee:
A few years ago I was over at the coast wheeling the dunes. We found a stream crossing with the perfect bank on the other side to jump. Through the creek up the bank - airborne! Messed around doing this for a half hour or so, got bored and finally moved on. Just around the bend (behind a dune) there was a Humvee with some Marines standing around. The right front wheel was pushed up - it broke the rf fender and busted up the hood. The lower control arms had let go. We asked them what happened - they said "Right back there is a creek, we jumped that bank and the front end just broke..." True story.
Humvees suck.

 

Short answer:

to have something different.

Long answer:

It seems like the rock climbing of any rig is the weakest link. In the case of the 4runner, the IFS. So if you have IFS then it shouldn't make the rig less trail ready than if you added IRS.
But as it is pointed out, the IFS makes it better on the road. But also, if you look at Baja rigs, thy have both IFS and IRS. Making it a better and more controlable high speed off-roader.
It seems to me that if you were a serious off-roader that didn't do alot of slow rock crawling, like I do to go camping up in the mountains, the IRS addidtion might be pretty cool. I also like to go out to New Mexico and South Texas to do some desert running. And the rig is also my daily driver.

So the addition of IRS might be pretty cool.

As far as Rav4's , ridgelines on the trails. I don't think that is exactly what they are marketing towards.

Kent

 

Thanks a lot for explaining all this guys, you have no clue how thankful I am. Only thing that's left for me to do is go under my 4x4 4Runner and check out the IFS to get an understanding of how exactly it works. It must suck having so many CV's on there.

Again, thanks very much, this made me understand things much better and sorry for being such a noob in the first place.

Marko

 

the military humvee is not like any regular ifs/irs setup, i agree its very expensive, but thsoe can take a lot of abuse and htey do in real world situations....

 

What are the pros/cons of using the leaf springs vs coil springs when doing a SAS?

Seems like most people do leaf springs, but I've seen a few Wranglers with coils... ?

 

walker evens built a comp. rock crawler with ifs and irs and it did really well.

 

Yup then he switched back to solid axles because they were better.

 

Yep.
A lot of IFS crawlers were built a few years ago, and nearly all have gone back to solid axles.

 

Leaf spring installations are very simple to engineer and install. Leaf springs are inexpensive (relatively) and easy and inexpensive to experiment with, and can yield mad flex almost up to par with long coils.

Coil setups are more complex, and quite difficult to engineer for on-road handling and steering qualities. Not for the backyard engineer. The pieces are more expensive and subject to more stresses and have to be chosen carefully and the geometry of the multi links is Critical. All Wranglers from 1997 came with coil suspension, so naturally you see lots of em.

 

As always, thnx for the informative reply Flamedx4!

 

Allright, to resurrect my original question. ( but I liked the IFS/SAS conversation, I always like to learn more!)
This is all completely hypothetical mods, not a straight axle/IFS debate.
What if a total chaos Caddy kit could be set up in the rear. This would give long travel independant suspension front and rear. I wonder how good of a desert runner the truck would be, and what would it be like as a daily driver?
Always thinking of new mods I couldn't possibly do or afford