Stupid GM IFS question

Wilbah

Adventurer
So I have a GMC Yukon that I use for moderate off roading. I have offroaded since the md/late 70's (my '76 FJ40 was great!). But my Yukon is not built at all, just about 100% stock. But I have taken it all through the North Maine Woods, it's done Ophir, Cinnamon and Hurricane Pass (not that they're technically tough trails by any means) and a host of other places around the country and has really served me well (wife, 3 kids, dog...when we travel its like the Beverly Hillbillies! :) ). And lets face it, I also love what newer technology has given us! Things like fuel injection, ABS etc. have made offroading so much better in my mind (yeah I remember driving my '80 K10 (from MA) carbureted truck in the mountains of CO *cough wheeze* :( ) It serves as a DD as well and business/job issues have kept me from making the mods I would like. Anyway....whenever I see people discussing turning full size GM's into expedition worthy vehicles one of the first things I hear/read discussed is swapping in a solid axle in the front.


From the discussions I have read it appears to me that this may be more due to the desire to raise/lift the truck and the subsequent effects on the CV joints and other front end parts due to the angle changes than anything wrong with IFS in general for off-roading. Lots of SCORE 4WD racers have IFS so it doesn't appear to me to be something fundamental about IFS that's "bad" for Off Road. So is it because most want to lift their trucks and can't find better quality (i.e. stronger) aftermarket parts for the wear parts on the IFS? Is it something else? I would just think that with the number of GM full-size rigs out there some folks would build stout aftermarket parts to beef up these systems. I have seen some stronger pieces used in some of the builds here so I know there are some pieces out there, but I still seem to see an overwhelming # of folks preferring solid axle swaps and I am just curious. :)


I appreciate any feedback and I also want to thank everyone who takes so much time and energy posting here be it build threads, ATR's or other. The pictures and stories you post are invaluable as I plan the "next generation" of my rig. Really awesome to see how willing people are to share their experiences and efforts with everyone and thanks for any ideas/thoughts on my IFS question above.
 
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Buliwyf

Viking with a Hammer
As long as you have conservative, mild build ideas, The IFS is fine. It's when you "go big" that you surpass it's design intentions, and then it's better to SAS than to make the IFS work.
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I prefer solid axles. Easier to tune and lift. And absolutely tough. IFS also tugs on the tierods and ball joints every time the suspension cycles. And tugs with great speed and force. Something you don't see with a solid axle. That's why the GM's eat joints more frequently, but not a big deal unless you offroad too much or are using huge tires.
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285/75 r17 and a mild 2" lift is no problemo. And that's the perfect setup for most of my uses. Friend of mine just added a 2" preload spacer to the front of his 2010 f150 and it's working fine so far, nice and level with skinnier but taller tires. Around 33". I don't recommend the big IFS lifts on GM's anymore. There are decent ones out there though. Like the BDS 4".
 
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dddonkey

Adventurer
I think that people just under estimate the IFS systems. People will take their truck out and put a cheap lift on it, not re-gear, and then crank the T-bars so that they have horrible CV angles, then get upset when it breaks. People need to understand the limits of the system, or upgrade it to meet their needs. You can get pitman/idler braces, bigger tie rods, center links, and even better axels. The only thing that there is no real up grade for is the wheel bearing, and the factory ones are fine. The key is to have you CV angles as close to flat as possible and a good lift with a full center diff drop, this will also help the life of the ball joints. I don't care what rig you are running, bigger tires will put more wear and tear because of the extra mass they have.

Now if you are only out rock crawling, I would put a solid axel on the truck. Look at all the sled pullers in the GM's, they run there trucks hard with a IFS system in them. I would bet that most people are just miss informed or have money to burn.
 

Wilbah

Adventurer
Ridge I have wondered that as well....I don't know totally about the internals but just checking auto parts the lower ball joints are the same ('03 Yukon v. '03 2500HD), upper ball joints, upper control arms, tie rod ends, axle shaft bearings are all different for each vehicle. That was as far as I checked but there's obviously a lot different between the two.
 

DeweyH

Observer
i am in the process of building a 92 blazer , first years of ifs. its stock with 31 x 10.50's and plenty big enough for me
 

Haakon

Observer
Solid front axle also lets you put in a front locker, otherwise you're limited to open diff on the front. You can also get more articulation with a SFA, but unless you go really off road you probably don't really need either. Although a front locker can be handy if you run through mud or snow.
 

bob91yj

Resident **************
I just can't figure out why IFS is OK on Toyota's, Nissan's, Mitsubishi's, all 1/2 ton pickups, but put it on a 3/4-1 ton and it immediately sucks?

I'm a fairly hard core rock crawler by nature, completely understand the value of solid axles...haven't found the need for them on my Dmax. Of course I don't use the Dmax for the same things as my rock crawler. I'd guess 85-90% of all of my truck miles are on the pavement, 10% on dirt roads, and 5% truly "off road". I'll take the ride quality of IFS over a solid axle for that 95% of the time. Be smart (relative) the 5% of the time I'm off road and my IFS has held up just fine.

My rock Jeep, Wrecking Ball, The Hammers, Johnson Valley, CA. (the leak is not from my Junk)
wreckingball035.jpg


My truck is used for towing duties, as well as chasing a race car around the Baja Peninsula. It doesn't get abused, but it does get worked pretty hard. (keep expecting to find the roof air laying in the floor, hindsight, I should have mounted a window rattler in the back window of the camper)
fiestaislandculpvalley066.jpg


When nothing else works we have our LJ to fall back on. It's built to cover desert terrain at a moderate clip, still have some rock crawling capability, and it was my wife's daily driver for a few years. Loaded for a week of wandering around Baja in this picture.
2011bajaextravaganza113.jpg


And finally an indication that IFS is going to be the wave of the future in rock crawling, here's a shot of the front end of Ben Napier's King of the Hammer's car at last years event.
kohgage091_zps1501b5dc.jpg
 
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82fb

Adventurer
And finally an indication that IFS is going to be the wave of the future in rock crawling, here's a shot of the front end of Ben Napier's King of the Hammer's car at last years event.
kohgage091_zps1501b5dc.jpg

Totally disagree. IFS in KOH is only an indication that the race has a desert component.
 

dddonkey

Adventurer
Look at H1's, they are IFS. One other thing is that you can put a locker in the front diff off an IFS truck, I can think of 2 right now for the chevy, it is the same housing that the dodge uses 9.5" AAM.
 

bob91yj

Resident **************
Totally disagree. IFS in KOH is only an indication that the race has a desert component.
It'll take some time, but I see more and more new builds using IFS. Suspension travel was one of the biggest issues with IFS, the KoH and Class 4400 Ultra4 desert racers are starting to get some decent travel. There still the traction issue to overcome, but with the increased travel that is becoming less of an issue.

The home brew builders will stay with the solid axle forever, it's too stupid simple to work with not to.
 

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