Benefits to SAS besides Flex

Just to throw this out there first, I am not the guy that wants a SAS because it is cool or its cheaper, I want to put it to work rock crawling. Currently I have a 6" IFS lift and 35's on an '01 Ext Cab. I really like the height and for crawling the setup isn't too bad b/c I get my back to flex alot. What kills me about it is the ride is so rough, which is inevitable with the IFS lift. I am considering to go to SAS for a) the flex up front, but b) I was also hoping that it would smooth out the ride alot so I could go faster down the trail than with the IFS. I test drove a SAS and found that the flex was great, but the ride was super rough still, and I couldn't drive down the trail much faster with this particular SAS than I could with my IFS. My questions is, is this characteristic of all SAS, or just the one I drove? If this is the case for all SAS, I think I might just stick with my IFS setup. Thoughts?

 

Every truck will handle differently depending on how the suspension is setup. Some will ride soft and some rough.

As for other benefits, the big one is the flex but also being able to build an axle that can take the abuse of larger tires in high stress situations without breaking.

 

Sounds like you need a suspension set up that better suits your needs. IFS should ride smoother than SAS if set-up properly. I agree with Fire931 though, SAS is more for strength. A 4wd LT kit will have lots of flex but won't take as much abuse as SAS.

 

I will admit that my suspension is getting worn out. I bought the truck used with the lift already installed as my first truck just to get started, figure out what I liked, and then when I figured out exactly what I wanted, go out and build my own the right way.

 

Higher than 3" lift without a Drop Bracket.

 

Stronger, stability, larger tires, more ground clearance, alignment is easy, its all build your own, not bolt on a DB kit or a LT kit. Plus it DOMINATES IFS in rock crawling it's almost sad.

Read this build, cry, poop your pants, become scared, and live life.

http://www.pirate4x4.com/forum/showthread.php?t=616611&highlight=

 

hoh lee hell! that thing is over the top. Think i can build that for 3,000 if i find some good used parts and fab myself?!

 

no...

 

He did build it all himself, and I'm sure he had some used parts. Good luck...

 

I hate to sound existential, but it is what you make it.

In general terms, a suspension that uses leaf springs will be a rougher ride than a coil and shock or coilover setup. Notice I did not say harder, stiffer, or firmer. Springs control the weight of the vehicle and links control the vehicle dynamic characteristics.

All that being said. If you want to know which one is better; IFS or SAS, it really depends on what you are doing. But also keep in mind, this an apples and oranges comparison. To get a IFS setup to be as strong as a solid axle, you are spending some serious money. Just ask Shannon Campbell...

 

The ride quality can be greatly changed on the very same vehicle through differences in springs and shock absorbers.

For example, a weak spring with a lot of arc will yield a softer ride than a stiff spring with little arc, though the two may yield the same ride height. The weaker spring with more arc will have more "sit in" to yield the same ride height, but smaller variations from above will cause the spring to compress or retract.

Typically, you would want to go with a stiffer spring if your objective is to be able to support a large variation in weight. This is why a buick will ride like a sofa and a dump truck will ride like a brick.

Shock absorbers are the other piece of the puzzle, and they're an enormous piece, because there are so many variations possible. In general, a shock absorber that resists motion more, will yield a rougher ride than a shock absorber that moves freely. Of course, there are a lot of variations in just how a shock absorber can be configured to resist motion -- downstroke vs upstroke, the rate that resistance increases with motion, bypasses to allow the shock absorber to behave differently at different points in the stroke... for example, you might want the resistance to increase as it approaches the limits of its travel during the downstroke, but move more freely when it is around the center. When you're hitting a real nasty bump at high speeds, you want the shock absorber to resist more in order to resist bottoming out. When your wheel drops down into a hole, you will want that wheel to drop out quickly to hold your frame level, but not so quickly that it snaps against its limits.


So in general, your process for suspension setup works like this;
1) pick your ride height.
2) determine how your weights are going to vary.
3) decide how much spring deflection is acceptable at your payload limit.
4) pick a spring with the lowest rate and greatest arc that will yield a ride height range that suits you.

Now comes the fun part that is, to be honest, way more than I am capable of advising you on....
5) Do NOT buy off-the-shelf shock absorbers. Go to a "really good" shock guy and get yourself something custom. He's going to ask you lots of questions about the terrain you drive on, the loads you carry, how fast you drive, spring rates, arcs, etc. From here, he is going to make a shock recommendation and give you an initial set up. Naturally, the better the ride you want, the greater the price. Also, you may need to go back for adjustments/tuning/finetuning a few times before the shocks work the way you need them.

Oh, and if you want the suspension setup to be right... you can forget about doing it for $3000, you'll be WAY over $3000 on the shocks alone. The reason why factory/OEM shocks are the price they are, is that they do the R&D only once and spread it out over every one of the thousands they end up making. A truly custom setup will make you hurt. BADLY, so you'll really depend on those custom shocks to mitigate the butt hurt.