SAS/SAC debate thread

[xcmountain80]

I dunno but this thing has IFS
http://pirate4x4.com/gallery/main.php/v/shannon_campbell_s_new_koh_rig/DSC_0304_2.jpg.html

Aaron

 

[4Rescue]

I dunno but this thing has IFS
http://pirate4x4.com/gallery/main.php/v/shannon_campbell_s_new_koh_rig/DSC_0304_2.jpg.html

Aaron

Touche' Sir... Touche'

That looks sweet. I would love to take a spin in that thing. Is KOH a "rock racing" series??? Or is it open class desert racing, does anyone know??? It's pretty interesting to see a custom built IFS on something other than a full on Desert Race truck. What's crazy is that with all of that rear flex the front almost doesn't need as much and they can hit things harder with the IFS style suspension action/cycle up front. I REALLY want to see this thing out on the trail now to see how it works. Oh, and why is the upper cab/cage built asymetrical??? Does anyone else see that??

Edit: Oh I see "King of the Hammers 2009" that looks brutal. I can't imagne "Racing" on the Hammers.

Cheers

Dave

 

[cruiseroutfit]

Touche' Sir... Touche'

That looks sweet. I would love to take a spin in that thing. Is KOH a "rock racing" series??? Or is it open class desert racing, does anyone know??? It's pretty interesting to see a custom built IFS on something other than a full on Desert Race truck. What's crazy is that with all of that rear flex the front almost doesn't need as much and they can hit things harder with the IFS style suspension action/cycle up front. I REALLY want to see this thing out on the trail now to see how it works. Oh, and why is the upper cab/cage built asymetrical??? Does anyone else see that??

Cheers

Dave

There have been a few IFS "rock-crawlers", this being one of them, built for the KOH race. The first that was really built to compete was the Walker Evans IFS/IRS buggy, very neat. I competed in UROC during that time frame and was able to see it perform on the rocks. I have no doubt we'll be seeing more of this in the future.

 

[ntsqd]

Even a Leaf-sprung Live axle will MASSIVELY out flex an IFS rig. I tend to agree that people see these SFA'd trucks out crawling and get a far away look in their eyes, and yes I think that they're way over-hyped espescialy among this crowd that really needs the smoothness livability of the stock IFS far more than the Extreme flex an SFA gives you...

BUT:

They are far more durable over time and have fewer easily worn parts. My ascertion of using a leaf sprung set-up is that it simplify's the system compared to some of the often drooled over multi-link C/O itterations out there. Having leafs, to me is a durability and simplicity issue. Like I said, it's far easier to limp out with a hobbled together leafpack then with a broken radius arm. Not that either is fun, but one is certainly easier.

Honestly from a "Ride" stand-point I think it comes down to the particular driver more than anything. To me, I LIKE a "truckish" ride and actualy expect it... that's why I bought a TRUCK. I always fnd it funny whaen people complain about the rough ride etc... Same with the noise and the handeling. Drive slower and pay attention to the vehicle. It's pretty clear that vehicle dynamics are a lost art to the average Red-White and Blue'r. It's a truck, and all of this griping and "wussifying" of the modern 4x4 is what leads auto-makers to make garbage like the H2 etc. and NOT offer us things like the HDJ80/105 etc. because Americans are SOFT. Hate to say it, but we are, it's readily apparent by our buying stats...

Cheers

Dave

When I talk about ride quality I'm not talking about trying to make it ride like a Mercedes 600.

What I'm talking about is can I do 60 MPH down Saline Valley road with no obvious beating on the truck, or will 15 mph punish the truck so badly that I'm not sure what I'll actually pull into the springs with. If I can do 60 on that road (asking a lot!), then within reason I can drive at whatever speed I wish and enjoy the trip. If I can't exceed 15 then I have to pay attention to every little softball sized rock, and that makes for along day.

The reasoning behind using FJ80 radius arms is specifically to take advantage of the OE designed-in durability, not to mention replacement parts. I'd use the FJ80 trac-bar too, if it will work. If not, then a custom tube (easily fixed, or even made, by welding) fitted with FJ80 TRE's for a trac-bar will solve that problem.
The downside to a leaf srping is that if you fail one you've lost that corner's spring and possibly that corner's axle location. By using a robust OE linkage design a failure means that you've only lost one or the other. Losing both at the same time probably means that you've got much larger problems.

 

[devinsixtyseven]

Very important to keep in mind that those IFS rock crawlers are completely different animals than our trucks simply because of the drivetrain.

It's not about the suspension at all.

Running a solid front axle means greater turning angle, since articulation doesn't restrict the outer drivetrain joint's turning arc. It also means a much easier time adding a hydraulic assist to turn larger tires, unless you're feeling like custom knuckles and a Howe rack on your Tacoma. Finally, it's less difficult to piece together a very strong solid axle using off-the-shelf parts, versus twice the joints plus custom housing of an IFS setup of equivalent strength. The outcome would likely resemble the Campbell KOH buggy. Few (any?) have done anything similar to their Toyota.

The suspension configuration really doesn't matter, IFS vs SFA...it's the relative strength we've imparted to the two configurations by virtue of their standard design, cost of ownership and impression of complexity.

It's been hinted at, but not said outright yet...the IFS frames don't have the same clearance in front as the solid axle configurations. That is what limits compression travel, and can result in excess height. I like having 6"+ compression and about the same amount of droop...running difficult trails (ledgy, with boulders) with 2-3" compression was a jaw-clenching nightmare.

Still waiting for Wil to post up regarding what's breaking that has him leaning toward a solid front axle .

-Sean

 

[01tundra]

I've had the pleasure of trying out both IFS and solid axles and I won't be welding any A-arms back on anytime soon......

My four leaf springs have seen long days of interstate travel, some of the toughest trails across the US, water, rocks, mud, etc and have never let me down.

Now leaf springs vs. linked suspension is a whole other argument that I have even had with myself over the years. I chose the durabilty of leaf springs for my particular use and have finally after much effort got my rig dialed in to be able to run the rougher stuff pretty good with about 3.5"-4" of compression....that doesn't mean I'm going to be running down washed out dirt roads doing 60 MPH, but that's not my thing so I wouldn't do it if I could anyways. But in my personal opinion, military wrapped leaf springs are about as tough and dependable as it gets.

It really boils down to what you're planning to use your rig for, if it's desert/high speed stuff then long travel IFS is the only way to go IMO.....for anything else....I will always choose a solid axle rig over IFS for what I like to do.

And I will definitely call BS on "the engineers know best", the engineers do what their bosses tell them to do - make vehicles that fits the need of the majority of the population, keep cost reduced, and make it safe for anybody to use.....oh yeah forgot one....and in the case of the 1st Gen Tundra.....use any leftover Tacoma parts we have laying around to build it 'cause nobody's going to ever do more than drive on a gravel road with this thing........

And no matter what Sean says.......we are getting closer and closer to converting his way of thinking.....he just decided to start on the wrong end first !

 

[xechcorx]

Those buggys use no off the shelf parts, and involve extremely custom fabrication, and VERY advanced design principles. Thats really not a fair comparison to this discussion. It'd be no different than posting Gravedigger and saying that its got a solid axle and takes the jumps and bumps. Now, I'm not supporting either "side" of the discussion, I firmly believe each has distinct advantages and disadvantages, and it's up to the owner of each truck what balance he wants on his vehicle.

I have personally owned IFS vehicles all my life, and wanted a SAS for a change of scenery, and a "cheap" trail truck. Well that kinda went to the wayside once I decided on the Cummins, and decided on cutting no corners. So I've now got a linked truck all the way around. One other concern is while using toyota 8" diffs you can gear all the way from 3.07 to 5.29 or maybe even a bit humerically higher than that. With IFS your gearing options are more limited. So if you're trying to toss in a diesel, you will need some overdrives and such. Once again a particular set of disadvantages and advantages specific to a truck and its owners choices.

 

[devinsixtyseven]

And no matter what Sean says.......we are getting closer and closer to converting his way of thinking.....he just decided to start on the wrong end first !

:hehe: Yeah...

If I could get a similar setup to that IFS buggy, I'd take it...but if I can get 4"+ compression on a solid front end, it'd be a lot easier to build a drivetrain that suits a 6500# truck! We needed LC parts, wish I knew why they used Tacoma takeoffs...

...yeah it is a lot of advanced design and custom parts, but advanced design is 100% necessary if you're re-engineering the front of your vehicle. Plus, if you make it simple and strong--or overbuilt for its intended purpose--the likelihood of breaking something is about nil...especially if overland is your goal as opposed to truck trials. Raise your hand if you've taken a rooftop tent through Pritchett...

 

[01tundra]

It wasn't that long ago that you were thinking you would never let a complete stranger that lived several states away take a plasma cutter to the tub of your rig......I suppose I'm going to need to pack up the plasma and make a run to CO soon !

I had the pleasure (I think that was what it was anyways....) of finding out that if you plan to play a long way from home, the most important thing to keep in mind is parts availability. I have just completed a defleecing of custom parts from my rig, now I only run parts that can be purchased at a Napa Auto parts in rural America. Doing things like using the exact same rotors, calipers, & hoses can also make life a little simpler.

 

[BigAl]

It seems these threads always have 2 distinct camps

1. I love my SAS

2. I would never do it, here's why, IFS is fine for what I do



I have trouble finding value in the arguments from camp 2. I can instictively say "I don't like turnups", but the truth is, I've never eaten a turnup so I really don't know

I'd look for a couple of guys that have done the exact swap (truck/axle/suspension) you want to do and prompt them for the pros/cons.

 

[jh504]

When I am building an IFS rig my ultimate goal is always to end up with a solid axle. I just went back to an IFS Toyota from a solid axle rig and I am nervous everytime I get out on the trail. As soon as budget will allow I will be putting leafs all the way around and a SAS up front. Simple and strong. I will be keeping the lift height low though, around 4" or so.

 

[Pskhaat]

I ask this in all due sincerity, but why start with an IFS rig if you are planning on eventually building it for a live axle?

 

[tdesanto]

I ask this in all due sincerity, but why start with an IFS rig if you are planning on eventually building it for a live axle?

I would tend to agree here. Unless there's a cheap way to add a solid axle to a vehicle, I would think starting with a solid axle would make more sense.

 

[Martinjmpr]

2. I would never do it, here's why, IFS is fine for what I do



I have trouble finding value in the arguments from camp 2. I can instictively say "I don't like turnups", but the truth is, I've never eaten a turnup so I really don't know

The above is only true if you assume that those of us who favor IFS have never had any experience with other SFA vehicles. As I stated above, I've got plenty of experience with SFA vehicles: 1957 Travelall, 1967 Travelall, 1971 Blazer and 1985 Toyota 4x4 pickup. So my support of IFS does not come from lack of knowledge about them. If anything it comes from too much knowledge about their limitations and down sides.

Manufacturers (including both Toyota and Land Rover as well as every domestic manufacturer) have switched most of their vehicles to IFS not out of some sinister desire to 'neuter' these vehicles but because of the simple fact that for the vast majority of users, IFS is perfectly adequate (and superior to SFA in most applications.) Big, heavy duty rigs like the F350 and purpose-built off-road vehicles like the Jeep will continue to have SFA for at least the immediate future but for all other applications, IFS has established itself well.

 

[Martinjmpr]

I would tend to agree here. Unless there's a cheap way to add a solid axle to a vehicle, I would think starting with a solid axle would make more sense.

Yes, I think perhaps the question posed by the OP is backwards. IOW, instead of asking "how can I give my IFS Toyota the capabilities of a SFA vehicle", it would seem to make more sense to say "how can I make my SFA vehicle of choice (FJ80, LR, Jeep, etc) as reliable and useful as my Tacoma?"

IOW, take what you like about the Tacoma and apply it to the SFA vehicle of choice. I would think that would be considerably easier and less expensive than trying to SAS a Tacoma.