# Cranking up the T-Bars



## Hambrick & Co. (Nov 17, 2007)

I know this has probably been posted before but I want to tighten up the T-Bars on my 2005 Chevy Silverado 2500 HD 4X4. The front end is a little low when the plow is on and in the up/ travel position. How many turns do I turn the bolts? Are they the bolts on an angle underthe driver seat? Obviously I would do this with the plow off and then put the plow back on to test it correct? Any help would be greatly appreciated. Thanks Mike


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## mikelawtown (Dec 5, 2004)

1st jack up the front end to get the load off, then look under the floorboard/seat area for a long bolt with the head(3/4) facing down. (one on drivers and pass side) use a 3/4 wrench and turn clockwise 3-4 turns,(lube 1st) make sure u keep track of the turns and then in the spring just turn them back..Helps alot and is FREE..


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## 06HD BOSS (Nov 28, 2005)

Like mike said. jack up the front end, but i think the bolts are 15mm. i turned mine 4.5 turns


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## Hambrick & Co. (Nov 17, 2007)

Thanks for the help....


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## B&B (Nov 4, 2006)

Do not do anything until you take a few measurements.. measure the front and rear height at the body line right in front of the rear wheel well, and right behind the front wheel well. These 2 measurement will tell you how much lower the front is than the back AND most importantly it will give you a reference to return the truck back to the stock height if you ever decide to.

Generally what you want to do is level the truck front to back BEFORE you attach the plow. Just getting it level will make it carry the plow fine..do not adjust the bars with the plow weight on the truck, it will make it too high once the plow is removed.

After you have your measurements, jack the truck up until the front tire are off the ground, spray some lubricant of some type on the adjuster bolt threads and turn each bolt clockwise the exact same amount on both sides with an 18 MM socket..(make a note of how many full turns you turned them so you can also use this as a reference later if needed.

Depending on how far the truck needs to come up in the front to make it level, I'd start with about 3 or 4 full turns and then take the truck for a quick spin around the block to resettle the suspension (important). Re measure it again and see where it's at.. if it needs to come up more, give it another turn or two.. don't be surprised if you need to go 6 to 8 turns or more to get it level as these trucks are pretty low in the front to begin with. Once you get it level, stop. Don't turn them anymore than it takes to get it level. This will give you the height you need without grossly changing the suspension geometry any more than needed.

Torsion bar suspension isn't black science but to guys that don't understand it it can be.


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## Hambrick & Co. (Nov 17, 2007)

Thanks B&B


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## PlowMan03 (Dec 31, 2003)

After you mess with the torsion bars aren't you supposed to get an alignment right after wards so it don't chew up your front tires? Thats what I've been told a few times.


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## B&B (Nov 4, 2006)

PlowMan03;483089 said:


> After you mess with the torsion bars aren't you supposed to get an alignment right after wards so it don't chew up your front tires? Thats what I've been told a few times.


It depends on how much you actually need/want to raise the truck. So it's more of a "possibility" that a definite "yes"...but it never hurts to have one done regardless.

An inch I wouldn't bother with it, anymore than that, yes I'd have it checked as it does affect the toe and camber after changing it a certain point.


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## JD Dave (Mar 20, 2007)

B&B;483044 said:


> Do not do anything until you take a few measurements.. measure the front and rear height at the body line right in front of the rear wheel well, and right behind the front wheel well. These 2 measurement will tell you how much lower the front is than the back AND most importantly it will give you a reference to return the truck back to the stock height if you ever decide to.
> 
> Generally what you want to do is level the truck front to back BEFORE you attach the plow. Just getting it level will make it carry the plow fine..do not adjust the bars with the plow weight on the truck, it will make it too high once the plow is removed.
> 
> ...


You should make a sticky about t-bars, you explain things very well.


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## DeereGuy (Dec 12, 2003)

*gm notice/warning*

I was at the Fisher dealer having a plow install a week ago and asked about turning up the t-bars. He gave me a notice to read from 
GM about the possible braking of the shock and subsequent brake line damage: read, no brakes, big crunching noise when you hit that tree. I didn't do a search so maybe this is not news but I was a little surprised at the warnings.


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## B&B (Nov 4, 2006)

DeereGuy;483150 said:


> I was at the Fisher dealer having a plow install a week ago and asked about turning up the t-bars. He gave me a notice to read from
> GM about the possible braking of the shock and subsequent brake line damage: read, no brakes, big crunching noise when you hit that tree. I didn't do a search so maybe this is not news but I was a little surprised at the warnings.


Gm has been sending those out for years...they also include it in their up fitter manuals too.. The main reason they did it is from guys OVER adjusting the T-bars..

These IFS trucks have a specific "working travel" and their is a spec to ensure it stays in this range (GM calls it the "Z-height") in the front suspension that is engineered into them (not _total_ travel,"_working_ travel"), and if it's exceeded can cause problems. As long as you don't get crazy with the adjustments their is nothing wrong with a T-bar adjustment. Why do you think they're designed with an adjustment capability in the first place?..Because not all trucks are used the same or or optioned exactly the same..and GM knows that some of these trucks will be outfitted with additional weight by the end user. So by designing the suspension to be adjustable, allows the capability to re-adjust the suspension back to "working travel" specs.


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## DeereGuy (Dec 12, 2003)

Thanks for the explaination B&B.


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## B&B (Nov 4, 2006)

JD Dave;483140 said:


> You should make a sticky about t-bars, you explain things very well.


Thanks JD... you might be right, this one and a good write up about duel battery installs would be perfect stickies in the Chevy forums...since they seem to be the biggest discussions in this forum.

Glad the explination was helpful to you DeereGuy..


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## saabman (Sep 20, 2007)

As the risk of stating the obvious, added spring rate is what you need to handle a plow not additional static hight (T-Bar cranking). Any raising you do to handle to deflection of the truck with the plow will leave the truck nose "up" when undocked.

Timbrens make the effective spring rate higher without raising the static ride height.

The other option (pricey) is to get beefier tbars. The bigger diameter of the tbar is what gives it a higher rate.


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## William B. (Jul 22, 2004)

Here is a good site that explains how to adjust the TBars. It even has pictures

http://www.offroad-tech.com/tech/tb401/

If you are looking for height and a little more travel look into possibly a leveling kit from Cognito. Again here is another write up about it with pictures

http://www.norcaltruck.com/cognito-2-3.html


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## B&B (Nov 4, 2006)

saabman;483464 said:


> As the risk of stating the obvious, added spring rate is what you need to handle a plow not additional static hight (T-Bar cranking).


Generally yes, the more weight you add, the more spring rate you'd want. But that doesn't totally apply to the T-bar suspensions on these trucks because a torsion bar suspension isn't as "liner" as a leaf or coil spring suspension. As long as the bars aren't too undersized for the job (most aren't if the truck was optioned correctly), you can imitate a higher spring rate without changing to a higher capacity bar on these GM trucks. And the way you do it is by raising the truck. When you raise these trucks, not only are you changing the static ride height, you are also changing the pivot point where the T-bar exerts it's twisting force in relation to the pivot point in the lower control arm. As you raise the truck, the C-arm is pivoted down and in, in relation to the mounting point on the frame (where the C-arm pivot point is) By doing this, your changing the mechanical advantage that the T-bar has on the ability to support it's load (the truck). Your basically creating a "fake" increase in the spring rate in the T-bars by making the job easier for T-bars to support the load.

A simple and easy to understand example of this: If you get down on the floor to do push ups, are they easier to do with your hands right beside your body or are they easier with your hands 2 ft on each side? Of course they're easier the closer to your body they are...why? Because you moved the force closer to the load, not because your arms suddenly became stronger...well actually they did, but only because you moved the force closer to the load....same thing with the GM T-bar suspension. Has anyone noticed that guys find that after they installed a plow the truck drops a ton when the plow is lifted but after you turn the bars up to level the truck, the truck drops much less...why is that? You didn't physically change the spring rate of the bars, but by raising the truck, you changed the pivot point and thus the mechanical advantage that the bars have to help carry the weight. It's the same thing as moving your hands closer to you body in the push up example.



saabman;483464 said:


> Timbrens make the effective spring rate higher without raising the static ride height.


Nothing wrong with running Timbrens..but a T-bar adjustment (not an over adjustment) should be done first..Some trucks aren't equipped with the correct T-bars for a plow application and in that case may not provide enough capacity to carry the additional weight, even with an adjustment (again with over adjusting them). So then yes, a set of Timbrems aren't a bad idea..


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## Hambrick & Co. (Nov 17, 2007)

OK so it sounds like half favor cranking up the T-bars and half don't go figure..... What is the diffrence between installing Tims and installing a Truxxx leveling kit. Would either one of those options definetly solve my problem? 2500 HD Plow Prep Package (2005)


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## JD Dave (Mar 20, 2007)

Hambrick & Co.;483662 said:


> OK so it sounds like half favor cranking up the T-bars and half don't go figure..... What is the diffrence between installing Tims and installing a Truxxx leveling kit. Would either one of those options definetly solve my problem? 2500 HD Plow Prep Package (2005)


The trux leveling kit includes key and shock extenders, which what for you want won't do any better then stock. The timbrens are basically just a stop to keep your suspension from bottoming out. If you crank your stock keys a bit and add the timbrens, you'll be all set.


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## Hambrick & Co. (Nov 17, 2007)

OK so if I install the tims. which I can get at CPW do I need to do front and back?


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## saabman (Sep 20, 2007)

Just the front, they are passive until you load the front (and the plows weight is primarily borne by the front axle)


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## saabman (Sep 20, 2007)

> The trux leveling kit includes key and shock extenders, which what for you want won't do any better then stock. The timbrens are basically just a stop to keep your suspension from bottoming out. If you crank your stock keys a bit and add the timbrens, you'll be all set.


I disagree that Timbrens are just a stop. What you remove to put them in is the bump stop which has a much lower profile. If you put a Timbren in a hydraulic press you can see it has a fair amount of deflection when squeezed (this is why you have to reverse the lower shock bolt)



> Generally yes, the more weight you add, the more spring rate you'd want. But that doesn't totally apply to the T-bar suspensions on these trucks because a torsion bar suspension isn't as "liner" as a leaf or coil spring suspension. As long as the bars aren't too undersized for the job (most aren't if the truck was optioned correctly), you can imitate a higher spring rate without changing to a higher capacity bar on these GM trucks. And the way you do it is by raising the truck. When you raise these trucks, not only are you changing the static ride height, you are also changing the pivot point where the T-bar exerts it's twisting force in relation to the pivot point in the lower control arm. As you raise the truck, the C-arm is pivoted down and in, in relation to the mounting point on the frame (where the C-arm pivot point is) By doing this, your changing the mechanical advantage that the T-bar has on the ability to support it's load (the truck). Your basically creating a "fake" increase in the spring rate in the T-bars by making the job easier for T-bars to support the load.


So you are suggesting that the angular change in the Lower Control Arm (LCA) will exert less angular force (at static height) on the tbar. Coil springs in a double wishbone suspension are not all the different. The control arms sweep an arc with varying angle to the ground. Most vehicles are set up to have the LCA parallel to the ground.

We are probably getting in a bit to deep here.


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## B&B (Nov 4, 2006)

saabman;483741 said:


> So you are suggesting that the angular change in the Lower Control Arm (LCA) will exert less angular force (at static height) on the tbar..


 Somewhat, but your not looking to actually lessen the force as much as your giving the T-bar "extra advantage" by moving it further below the C-arm pivot point. It doesn't change the load the bar sees, it changes the way the bar can deal with it.


saabman;483741 said:


> Coil springs in a double wishbone suspension are not all the different. The control arms sweep an arc with varying angle to the ground..


 When I said "linear" I meant in reference to weight vs suspension capacity, not range of travel. 


saabman;483741 said:


> Most vehicles are set up to have the lower C-arm parallel to the ground...


Sure, on an IFS set up many of them are designed that way, since the more parallel the lower c-arm is, the less scrub your going to have throughout the arc that the suspension travels in....but not on a GM IFS 4X4, since the factory Z-height spec doesn't even set the C-arm to be level in the first place. That's the way they're designed..

Anybody ever notice the lower c-arm angle's on an H1 Hummer? 



saabman;483741 said:


> We are probably getting in a bit to deep here.


 For the guys that don't care and just want to know what to do to help their truck hold the weight of a plow, yea you could be right .


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## Hambrick & Co. (Nov 17, 2007)

Thanks for all the responsed I think I now know what I am going to do.


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## tkrepairs (Nov 28, 2007)

as far as things breaking because the t-bars were overadjusted.... when you jack the truck up off the ground the front wheels hang down as far as they are ever going to go. they aren't going any further without modification. the brake lines and shocks are designed to go at least this far. how is cranking the t-bars going to affect this? the wheels drop a long ways when jacked up - the t-bars lift the truck a couple inches at max. how do the t-bars break brake lines or anything else?


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## B&B (Nov 4, 2006)

tkrepairs;484491 said:


> as far as things breaking because the t-bars were overadjusted.... when you jack the truck up off the ground the front wheels hang down as far as they are ever going to go. they aren't going any further without modification. the brake lines and shocks are designed to go at least this far. how is cranking the t-bars going to affect this? the wheels drop a long ways when jacked up - the t-bars lift the truck a couple inches at max. how do the t-bars break brake lines or anything else?


Because the shocks on these truck are just long enough to do the job, and what happens when you actually drive it with the over adjusted T-bars (not just at static droop on a jack), it pulls on the shocks every time the suspension "tops out" since it's already close to being topped out if the bars are over adjusted. And the droop stop bumper won't protect the shock from being pulled against when it's hammering against the upper C-arms droop stop on every rebound from most bumps in the road. After enough of it pulling on the shock, it will break the upper shock stud off the shock, which will then allow the shock to flop around uncontrolled, and can damage the ABS wiring or the brake line. That's why the bulletins went out.


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## tkrepairs (Nov 28, 2007)

well thats just an ugly design lol. a suspension that is allowed to be pushed past the physical limits of its components? oh well i love my truck anyway. doesn't even know its own strength.....


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## WheelerandSon (Jan 6, 2005)

you are not going to like the ride when you turn up the T bars


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## harley9202 (Nov 27, 2007)

Just a quite note on ordering from CPW, check the Timbren's website first and find the ones you need, then call to order. Don't trust them to give you what you need. They have screwed up 2 orders for me this year because I just told them what I wanted for my truck and they looked it up.

I installed Timbren's on my 2001 1500 and it made a huge difference.


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## abbert55 (Jan 13, 2006)

*T-Bars*

When I bought my truck "96" GMC 2500HD it had a Boss V-plow mounted on it. The dealer cranked the T-Bars exactly 4 turns and wrote this info on the rear of the T-Bar bracket. This gave just enough extra muscle to the front end without much noticeable lift or ride difference. I removed the Boss when I bought it and installed my Meyer 7.5 but didn't lower the T-Bars. There have been no problems either with the plow on or off. The suspension doesn't top out either. I am having a new Blizzard 860SW installed next week and don't plan to make any adjustments to the T-Bars. Hope this is helpful, Al


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