SAS or IFS upgrade

[Oobray]

Well expo folks, I'm looking to upgrade suspension on my truck (2002 Yukon XL 2500, 8.1) looks like the ORU SAS using a fixed up junkyard D60 will be about $4,500 ish and end up with 6" lift. After pricing the IFS steering and full suspension upgrades from cognito including bushings it looks like it wouldn't be too much more to go ahead with the SAS. My questions are...
1. Has anyone done this and what's the street ride like?

2. How much would towing be affected by 6" lift and prob 35" tires? This truck is what I pull my 7k lb camper with so it needs to be safe. In the short term I can compensate for the gearing by just using 3rd which will keep the truck in good RPM range until I can swap gears (of course assuming I can find a D60 with 3:73 to begin with)

This truck doesn't really see serious off reading. Mostly muddy fields, old forest roads and getting into public hunting spots. I would like to maintain decent speed on dirt roads without beating myself up though. I just figured if the costs of completely upgrading the IFS was about the same as the SAS then it might make sense. Main thing holding me back is the lift and how it would affect towing. Any experiences are helpful.

Thanks!!

 

[1stDeuce]

Call Stephen from Off Road Designs and talk to him a bit about your situation... He and I talked at length a while ago about the fact that the GMT800 platform needs some upgrades exactly like you're saying, and we tossed around some ideas. SAS is pretty much HUGE if you want it to work well, and huge is kinda ridiculous for most of us...

Perhaps if he hears from a few more people, we can get something brewing...

3" ish lift, push the front tire forward a bit to clear the body, trim the bumper, replace the stupid hanging-down crossmember, and perhaps add a skidplate or two. With the right springs/shocks, it would ride well, and do well enough offroad for a 7-8000lb truck. (Ie, not that far offroad...)

Chris

 

[1stDeuce]

BTW, SAS won't do much for the ride, unless you make it really soft and wallowy, which is NOT what you want for towing 7000lbs... I put Bilstein 4300 (?) shocks on my truck and couldn't believe how much better (softer) the ride got compared to running the Gabriel shocks that I had on it before. It will suck up pretty big stuff now, without breaking my back, or the truck. Washboard is still pretty rough, but the only fix for that is REALLY big tires, or airing down. I choose to air down and even washboard is not a problem.

 

[Oobray]

Ok, I'll call ORD next week. Def don't want "wallowy" but I know companies like Carlinmake pretty nice riding solid axle stuff for ford and doge. I guess those are could though. Firm but "controlled" would be ok, I just don't want to feel like a covered wagon on dirt roads or freeway overpasses.

 

[haven]

The chief advantages of SAS are: strength, articulation, simplicity and somewhat lower cost. A shade tree mechanic has a chance to do it him/herself. IFS is better for high speed bumps and general handling. From your description, I'd say IFS will be fine.

 

[HenryJ]

Upgrade the IFS parts as needed and invest in a GOOD set of shocks. Bilstein is a good choice and the best for the 800-900 GM platform , IMO.
Cognito is not the only option for HD parts. Much of the stock 2500 suspension is really very durable. I sleeved the rods so that I can use OEM replacements if needed. Another advantage to staying IFS is the availability of parts. No specialty parts needed and the counter person at the parts store can find them

Put some $$ into a good set of tires to soak up the terrain and handle the loads.

You don't have to get crazy in the upgrade to fix the weak points and add some performance. Upgrading shocks, sway bar bushings and sleeving those weak front tire rod end links can make a very reliable offroad rig. If you need to replace normal wear parts like the ball joints , CV boots and wheel bearings , do so. Save the $$ for fuel to get out and enjoy

 

[chilliwak]

I wish I had a cool Avalanche like you guys. Man that is some inspiration..:Wow1:

 

[ExplorerTom]

I took my IFS Explorer and SAS'd it.

Offroad there really is no comparison. Without pushing it, I'm faster through rocks and rough sections than rigs running IFS: I'm going like 5 mph vs their 3. Due to the significant articulation, I don't think I've lifted a tire since I've been SAS'd and therefore traction is rarely a problem. And the solid front axle has allowed me to run a traction device and not have to worry about snapping an axle. And the solid front axle allows me to run upgraded chrome moly axles for more strength. The steering is super strong now too due to upgraded links.

But the lift I gained when I SAS'd has made me feel tippy at times. My conversion, while it works pretty damn well, has taken some tweaking to make it better and I feel there is more tweaking to go.

On road it's OK. Due to the relocation of my sway bar, my tires rub the end links when it's connected so I can't turn too tightly- but still can do 90% of turns normally. The lift height also makes it tippy on the road- although not nearly as much when the sway bar is connected.

Would I do it again? Not sure. A lot of custom work went into mine and therefore there's a lot of places to influence how the vehicle performs outside of where the original design was. There are some days where I love my SAS and some days I wish I stayed IFS. For you: towing and muddy fields, I think I'd stay IFS. Get a winch and a Pull-Pal, a good locker for the rear and bumpers.

 

[pappawheely]

Keep in mind if you go with sas and a 6" lift you will need a different steering design, longer shocks and new driveshafts. I would not throw a tall block on the rear if you are towing. That means custom rear springs too. Once the snowball starts rolling you will have a lot of money invested, are you planning on keeping the truck a long time?