IFS really that bad?

[locrwln]

No.







There are some weak points, but overall they are a great riding, driving vehicle that still does well enough off-road for where they will fit. I had a leaf sprung SFA on my '02 Ford Superduty. It rode like a leaf sprung, SFA truck. My '07 2500hd, rides like butta'. My only complaint is the stock shocks last all of about 10 min (maybe) on the dirt before they fade out. Easily fixed, just not ready yet, still weighing my options.

I have had a 78 Chevy 1/2 ton 4x4, YJ Wrangler (many different suspensions), 88 4runner stock and SAS'd, 1999 GMC 1/2t Z71, 80 series Landcruisers (two different ones) with different suspensions, good but not great ride offroad, '02 Tacoma TRD stock and now my '07 2500. This truck has ridden the best of any of them. Although the 2500 does run out of suspension travel quicker than my 4" lifted 80, which it should as it is completely stock. On washboard, no comparison, chevy all the way, bigger holes, the 80 was better. Rockcrawling (I'm not talking about KOH rockracing), no question SFA is mo' betta'. But for general offroad exploration stuff, IFS works.

My Ford spent very little time offroad, with stock tires the entire time and the balljoints were trashed in about 80k miles. My Chevy has more miles and waaay more offroad and the ball joints are still like new. TRE on the Ford were like new at 96k (when I sold it), the chevy pitman arm and idler arm were in need of replacement when I did, TRE's were still like new.

If you think SFA in full size rigs are the end all, be all, just do a search on Dodge front ends from 1994 to present and Ford SD 1999 to present. You will find all sorts of BJ, steering, death wobble, problems. Each truck has some of it's own problems and some generations have different problems, but SFA aren't trouble free.

Jack

 

[rotti]

Amen Mr. Locrwin, that pretty much sums it up.

My twelve year old IFS Tahoe has been flawless and I only considered GM in my current 3/4 purchase because of the IFS.

 

[98dango]

Ifs has its place

For a back road explorer there amazing. Yes they have there weak spots so dose my dana 60. Pros to Ifs they tend to have more front ground clearance. The rid is great you can drive slow or fast all the same. Just driving is great you can run 35s or less with no worries if you keep up on the up keep. I have swapped out many an ifs did this for a living. I run solid axle's just because I play in rocks. The better half has 2 gm ifs products that will stay that way and on a long trip with little off road I grab the keys to either one before i get in my 86 or 94.

Yes for 96% of the world ifs be it t-bar or coil strut what ever will do. Its still like every thin else tho do what you want.

 

[Buliwyf]

Your IFS will be fine if you're just building a mild offroad expo rig. No need for a SAS unless you plan on running 38"+ tires, a front diff locker, and offroading more often and more agressively.

Just put in the highest quality ball joints, tie rods, and axle shafts you can.

My $0.02 on IFS vs SAS:

-it's really hard to make an IFS with good bumpsteer and good ackerman geometry. Usually they have poor geometry in both areas. Our GM's leave black marks in new concrete parking lots due to poor akerman settings even at low steering angles. I have to jump in our Ford tow truck If I have to maneuver a trailer on fresh new asphalt without tearing it up.

-IFS bumpsteer means that the suspension tugs on the tie rods every time you hit a pothole or bump. The suspension absorbs hits hard and quick, some of that force goes into the tierods as they toe the tires in and out as the suspension travels. Ironicly that desert type driving where people prefer IFS, is also one of the hardest enviroments for IFS.

That tug on the tierod, plus locked front diff, plus big tires has killed plenty of H2 tierods.

-Comparing street truck IFS to race truck IFS is just plain silly. They have nothing in common.

-mounting your springs as far out on the arm allows you to, allows you to use softer spring rates but maintain good roll rates. Why GM uses torque rods that have to be near the pivot of the suspension arm is beyond me. That is exactly where you don't want your spring for a nice plush ride. IMO the coil spring IFS that imports use are far better riding.

Good example: You can remove the front springs on a 04 Mustang and use coilovers that have the springs way further out. You can use much softer springs while actually decreasing roll. Effectively improving grip, especially in the bumpier sections of a track.

-not all IFS are plush. The 2011 GMC 2500 has a much rougher ride than the (normal front spring) 2005+ Fords I've driven.

-there is no hiding the lack of suspension travel. Since HD fullsize trucks often have stiff rear suspensions most of your flex is up front. This really hurts the bigger GM IFS trucks. Not everyone needs that flex, so that's ok. But if your after bragging rights at the ramp......

-The IFS extra trail clearance is only at slow speeds or gently going up hill. Don't forget that the diff drops when the nose of the truck deos. IE: braking, going downhill, rolling bumpy sandy roads. At times your clearance can be drasticly less than your static clearance when parked. There is a reason why solid diff skid plates are really, REALLY nice to have on an IFS truck.

If a fat kid sits on your front bumper your diff clearence drops, on a solid axle truck, your clearance is the same (E rated tires LOL).

-you can't deny the beef of a 2005+ Ford Dana 60. Giant Knuckles and sizeable tie rods. Just about tough enough stock for most locker use as well. While Dodge has had issues with thier version of the Dana 60, that's all fixable with better quality components, and a decent aftermarket trailing arm.

Bottom line for me: IFS is fine for smaller trucks, especially ones with softer rear springs, and may be excellent for less aggressive SUV type trucks, but for a HD fullsize, I want a solid axle every day of the week and twice on Sunday. And a HD Ford is a completely different feel and personality, than the GM's. That's not a bad thing, choose the one that suits you best.

And like said by others, you'll be fine unless you're really spending some serious cash to make a hardcore 4x4. Then it's worth the SAS. Otherwise, just optimize what you allready have.

 

[BurbanAZ]

ok its sounding like im going to just keep my ifs for now. I thought it would do fine for what i wanted to do with the truck and it seems like most people on here seem to agree with me. We take it on long trips but there arent extremely difficult, im not usually rock crawling or jumping though mud ( ive had bad situations on trips where the terrain was much worse than i expected but so far the suburbans done great) I do need to perform some maint. on it but its needed it for a while. I am pretty sure i need to replace the ball joints, and control arm bushings. It starts to shake over 70 and whenever i hit a sharp bump or crack in the road it rattles on the drivers side like there is excessive play somewhere. The truck has 188,000 miles and it doesnt look like its been replaced before so its to be expected. I plan on having this truck for a very very long time since here in AZ we have no rust so the frame and everything on the truck is still completely clean so im sure ill replace all major parts at some point and eventually i may go to a solid axle if i get tires of replacing ifs parts. Thanks for all the input everyone. I posted this same question on another forum im on that is more into mud trucks, and rock crawling and of course they acted like ifs is the worst thing in the planet. Its a good site but the people do seem to completely follow the latest trend, i feel the majority of people on here have a more unbiased opinion based on facts or experience.

 

[Saiyan66]

Alot of talk about better or worse comes from what people determine to be strong or weak. GM IFS is strong enough to survive hundreds of thousands of miles without much more than typical maintenance under normal conditions. Just remember that as the driver you have more control over how long your parts will last than anyone. CV shafts hate shock loads and high angles (just like any driveshaft), so smooth driving over rocks and obstacles will go a long way toward prolonging your rig's life. I have seen stupid drivers break Dana 60's with all the forged, billet, high end doo-dads on them. And I have seen careful drivers make it through insanely tough trails in mostly stock vehicles because they knew what they were doing and what their rig was capable of. If you take that into account, then IFS will serve you just fine.