Home Forums Gear Hunting Trucks and Four-Wheel Drives Lifting GM IFS With Torsion Bar Twist (Ol Toot and JJ)

Since JJ got me all spun up about how I leveled the front end of my '02 4x4 DMax, I wound up doing all the research I did last year over again. I have come to the same conclusions. Here is what I have found.

You can tighten the adjusting bolts on the torsion bar keys and raise the nose of the truck. This does not add any more stress to the torsion bars, it just "re-clocks" where the zero point is. Factory keys seem good for 1-2" of additional lift. Replacing the keys with after market units can give you up to 3" of nose lift.

Many guys think lifting the nose of a truck this way is bad and will cause CV joints to wear out prematurely. JJ has pointed out this has been an issue with Toyota IFS. Several guys who post on The Diesel Page have lifted their trucks by tightening the torsion bar keys--its a very common thing to do. No one has yet reported any CV joint issues--at least that I can find.

A friend of mine who lives locally has 295s on his Dmax. The dealership cranked his factory torsion bars almost all the way up to clear his tires. This is at least a 1.5 to 2" lift. My truck has 285s and I need about 1.75" of lift for my tires to gain the same clearance as his. He has run his truck for 67,000 miles with the big tires and cranked torsion bars. He frequently hauls a 16K dozer over some rough and rocky terrain. He has had no problems with his CV joints, ball joints, or even the girly-man little tie rods GM put of these trucks.

The company that sold me the leveling kit has been selling these kits for several years and they have had several trucks go 30, 40, and even 100,000 miles with the front ends leveled without any major problems.

I personally have had mine on for 15,000 miles and have no front end issues. All this leads me to believe raising the nose of a 2500HD a couple inches with the torsion bars is not a problem.

Hill Country says there isn't a problem with the 2500 HDs because the CV joints are not in a bind when the front end is leveled by 2" or so. Even with my nose raised, my truck has still has quite a bit of droop remaining in the front suspension.

Initially I had 265s on stock rims and a factory front bumper. From the stock setting, I raised the nose about 1.75", measured at the wheel wells and had the front end re-aligned. Later, I added a front end replacement (integrated bumper and grill guard), and needed another turn in the keys to keep the nose at it's 1.75" height.

Last week I installed 285s on 16x8 rims, and added another turn to the keys. The ride started to get a bit choppy. Then all the fuss about the lifting an IFS came up, so I got out my old measurements and played with the adjustments. Long story short, I am back at 1.75". Yes, I am accounting for the extra 1/2' in height the larger tires are giving me. The ride is very nice at this level. Any higher at all--even one turn, and the ride gets very choppy. Above 1.75", each turn gives me more and more lift. The folks at Hill Country told me that is where I need to stop to get the best ride.

I was considering a lift kit eventually, but now I'm not so sure. Many lift kits drop the rear torsion bar crossmember and the torsion bars themselves back down to stock height. So the 4-8" of lift you get is negated by having the torsion bars and that big torsion bar crossmember back down at stock height. I would only consider a lift kit--if anyone makes one--that kept the torsion bar mount and the torsion bars high. Such a kit would probably have to have longer front axle shafts and/or extended spindles to make everything work.

For Ol Toot: The fender wells are a good place to measure for the total lift on each side, but they are not necessarily even from left to right. To get the truck even from left to right, I measured from the concrete to the bottom of the frame rail just behind the aftmost vertical bracket just behind the wheel well (near the parking brake cable on the left side). This is the point where the frame slants down then turns level with the ground. My measurement--with 285/75-R16s at 50 psi--is 13.5" from the concrete to the bottom of the frame rails at this point. However, the center of my right side fender measures 40.25" and the center of my left side fender measures 40.625". A level placed across my bumper shows my truck to be level side to side. My concrete driveway also happens to be level at this point. After adjusting the torsion bars, you need to settle the suspension to get reliable measurements. I have found that starting the truck and simply turning the steering wheel from stop-to-stop then back to center settles the suspension nicely.

Blaine

AFP,
A picture is worth a thousand words (hint) <img src="/ubbthreads/images/graemlins/wink.gif" alt="" />

MtnHtr

Good post, AFP. You've got some sweat equity tied up in your rig. On going above 2" for these things, the u-joint cv issue pertained more to folks that run long periods in 4wd-hi range at hwy speeds where there's lots of snow and ice for long periods - more lift=more angle=more stress and wear. And, on ruff ground at moderate speeds & heavy bouncing, it can cause the stock front shocks to 'top out' and bust the piston stops and shock body but no problems with this using Bilsteins. Thanks, Blaine - good info.

Yeah, I know, I need a digital camera.....................

Toot,

Thanks for the info!

Check this out. A way to get the lift and keep the torsion bars out of the way.

http://realiftsusp.com/

JJ, I was hoping you'd see this thread and comment. It appears the the curent crop of GM IFS rigs have no issue with cranking the torsion bars up a couple inches, unlike the Toyotas.

Blaine

I guess I have no concern as mine is a solid axle and my Toyota is staying where it's at. If you guys with the GM trucks want to tinker, more power to you. I know I would want bigger then the dinky little factory tires. If I was so inclined to own a GM truck I would likely tinker as well.

Jim,

What I really want is four wheel independent suspension. Maybe I can find an old H-1 (the real Hummer) and build it into a dedicated hunting rig. I[i[hate[/i] the way the front and rear diff housings in staright axle rigs cut down on ground clearance, and I hate the way IFS lifts put the torsion bar and crossmember back down to stock height.

BTW, not only would you be inclined to tinker with a GM, you'd be inclined to tinker with a Dodge--which you did...............BTW, well done. <img src="/ubbthreads/images/graemlins/wink.gif" alt="" />

Blaine

I'll be in Portland on the 15th of Jan for a sportsman show on African hunting. To bad you will be in Texas!

That old "H1" Hummer is not all it's cracked up to be. Think about the area needed to turn it around, the size of the logging roads needed to drive it down, How underpowered they are, the relentless mechanical breakdowns that they have, and finally the real scary part, how many of our soldiers have died in Iraq driving them and wrecking them by rolling over in non combat accidents. The original Hummer is second only to Helecoptors for transport fatalities in Iraq right now. Hummers have had more crashes but helecoptors have involved more people per crash. There was an interesting article about this not long ago in a news magazine I was reading at the dentist office. There are appearantly lot of soldiers who really hate the hummer.

The IFS is a dangerous rollover hazard when done on all four corners, just like the original coil sprung willys military jeeps were. I'll stick with straight axles until I can own something with nice wide street legal rubber tracks!

I will be picking up my bumper when I'm down there too, it has a Warn M12000 winch. Check it out here:

http://www.buckstop.biz/dodge03.html

The Sportsmans show would be fun. I fully expect to be able to move back to the PNW in 4-5 years.

You really don't think I'd leave the Hummer stock, do you? <img src="/ubbthreads/images/graemlins/grin.gif" alt="" />

It would be completely rebuilt and re-engined...........................

From what I know about serious 4wheeling rigs, is that IFS is not a positive factor. The old Army 'jeep' the "M151A2 1/4 ton truck", with full independent suspension was known for it's knack of over turning. In fact, it's not even DOT approved for highway use. Which is why the average 'joe' can't buy one from the governement surplus sales.

The off-roading shows I've watched involving serious rock crawling all show solid axle jeeps climbing unreal rock formations. In fact, IFS keeps the center differential lower to the ground than solid front axles.

The only place I know that IFS excels over solid is high speed running such as the Baja 1000.

The original Hummer was cool, but no replacement for a normal truck. I do believe the brakes were mounted inboard near the 'pumpkin' which is in harms way of large rocks. The original 6.2liter diesel is not know for it's performance, and civilian models had to be introduced with better engines in order to sell.

Just my opinion here, but a person would be much better off starting with a Chevy, Ford, or Dodge when it comes to building a better off-road hunting rig.

The problem I see with the IFS is the boots for the CV joints are insufficiently tough . Any small hole or crack in those and you soon need a new CV joint .

I have replaced the CV joints on my old 88 K3500 three times now.............

Rock crawling is only one very limited application to four wheeling. I have no interest in it. What I want is a rig that can drive at a decent speed while providing a smooth ride over rough terrain.



The best rig I have ever ridden in for that was an old military Jeep. It was a USAF rig loaded up with over $100K of radios. We used to control aircraft over the drop zone in the pre-Hummer days. This Jeep was very top heavy due to the heavy radio equipment it carried. I didn't like driving it over 50 mph on the pavement. However, it rode superbly over rough ground at decent speeds.



The Z-71s I owned alo had a fantastic ability to travel at a decent speed over rough terrain. They were capable of much higher speeds than were the straigt axle rigs I have owned and drove in/ridden in.



For several years my wife's car was a '74 Jag XJ-12 with a Chevy 350 I built and a 700R4 tranny. The Jag had four wheel independent suspension, and was very stable at high speeds. Also, the guys I have talked to who have driven Hummers only complained about the ones with armor and a mounted M-2 (50 cal) machine gun in terms of being top heavy.



As such, I guess I just don't buy the 4 wheel IFS being inherently unstable at freeway speeds or consider it's not so great rock crawling performance as an issue. It is all in how you set it up. Yes, I want more "Baha-like" performance out of a hunting rig than rock crawling. As such, IFS is the way to go. BTW, they make some really beefy CV joints. Check this out:



http://www.bigelowgroup.com/