Zr2 front suspension

[Epsilon Plus]

31 minutes ago, Chuck FB said:

You need an official looking uniform and printed on your shirt "Inspection Osifer" 

 

If GM would have specs on the diameter of each rated torsion bar size, that would make it too easy of course. I am guessing that you found out from GM what the sticker part number is for that #4400 torsion bar and you saw it on that one unicorn truck and no measuring instrument was available. 

 

 

I opened the door and saw the 4400# FAWR. Was a contractor truck. I work for a muni so that's how I'm exposed to so many fleet style trucks. Just have to get lucky!

[Chuck FB]

Ok that makes sense, if you know the contractor or contractor company and if they are local, you might be able to track that same truck down if you can't easily find another one with the same spec. Of course depending on your local dealers they may stock some bare bones two wheel drive contractor trucks. As I have mentioned before that around here in the last number of years they just stopped bringing in two wheel drive trucks as the average joe has figured out they want a 4x4 for the winter and that goes for the half ton or the even smaller mid sized truck segment. 

[kylant]

would anybody like to sell their stock lower control arms?

if so, i would be interested in buying them

[Epsilon Plus]

On 3/17/2025 at 10:58 AM, GMCnewbie said:

Confirmed that my truck has the 4,800lb bars installed.  I took photos of both the Cognito and stock bars.  The Cognito bars only had a single sticker that was wrapped around them.  I had to take 3 pics to get the whole thing.  The Cognito bar is 1.02mm smaller than the stock bar.

 

 

 

 

I finally found a 4,400lb FAWR truck. Verified by door sticker.

 

 

When fully closed, this indicator is off by .0035. So the actual measurement is approx. 1.4865" or 37.757mm.

 

I measured fairly close to the sticker like newbie did. Unless these bars have graduated thickness, and given the likely error tolerances of our instruments, it looks we may have an answer?

Edited September 16, 2025 by Epsilon Plus

[revrnd]

4 hours ago, Epsilon Plus said:

 

I finally found a 4,400lb FAWR truck. Verified by door sticker.

 

 

When fully closed, this indicator is off by .0035. So the actual measurement is approx. 1.4865" or 37.757mm.

 

I measured fairly close to the sticker like newbie did. Unless these bars have graduated thickness, and given the likely error tolerances of our instruments, it looks we may have an answer?

You should be able to rotate the 'face/bezel' to zero the calipers when it's closed.

 

One of the locking screws locks the caliper, the other is for the face.

 

(Retired toolie who has a Mitutoyo brand dial caliper)

Edited September 16, 2025 by revrnd

[Chuck FB]

4 hours ago, Epsilon Plus said:

 

I finally found a 4,400lb FAWR truck. Verified by door sticker.

 

 

When fully closed, this indicator is off by .0035. So the actual measurement is approx. 1.4865" or 37.757mm.

 

I measured fairly close to the sticker like newbie did. Unless these bars have graduated thickness, and given the likely error tolerances of our instruments, it looks we may have an answer?

Isn't that amazing, I mean a complete fluke that Cognito by mere coincidence just happened to make their "special" torsion bar set the same diameter as a certain GM torsion bar which also happens to be the smallest diameter bar GM makes for these series of trucks. 

 

So was a price of a Cognito bar vs a GM bar set ( go with US prices ) get established to compare ? 

 

This also then goes back to my watching a youtuber in Texas who had a Duramax and his truck I believe would have had the 5600 lb rated factory bars and he installed a set of the Cognito bars ( which now with this info are highly likely to be the 44000 lb rated bars ) and he raved at the ride as did him claiming his wife was blown away and questioning what had he done to the truck to make it ride way better. Shows what happens when a softer bar is installed in a front end heavy diesel truck and turn the keys more to get the same ride height back.  Hard to say how much of a noticeable difference there is in a gas truck that has the 4800 standard units and dropping to the 4400 bars, it would be something but I assume not drastic. 

 

Oh and Epsilon, you've done very well ... and in the process managed not to get thrown in jail by some company thinking you were attempting to steal parts off their work truck LOL. 

Edited September 16, 2025 by Chuck FB

[GMCnewbie]

9 hours ago, Chuck FB said:

Hard to say how much of a noticeable difference there is in a gas truck that has the 4800 standard units and dropping to the 4400 bars, it would be something but I assume not drastic. 

It depends if the Cognito bars are in fact the same as the 4400lb GM bars.  If so, I have them on my gasser and the difference is noticeable for sure.  The same goes for the Cognito Comfort leafs.  I have both on my truck and the ride is much better.

[Chuck FB]

1 hour ago, GMCnewbie said:

It depends if the Cognito bars are in fact the same as the 4400lb GM bars.  If so, I have them on my gasser and the difference is noticeable for sure.  The same goes for the Cognito Comfort leafs.  I have both on my truck and the ride is much better.

Had you swapped the front shocks at the same time as the front torsion bars, just curious ?. I know you made so many changes to your truck with tire size and so forth but you also did it in some stages so I've forgotten what parts you swapped and then tried before going on to the next swap. Also before you did the torsion bar swap, has you turned the factory keys up or were they still at factory height as I know comments as well as an older truck I had turned keys up on, that certainly stiffens the ride unfortunately. 

 

As to the Cognito bars vs GM ones, I don't suppose anyone has photos of the markings on the front end of the bars under the assumption even GM kept the same imprint markings because I expect GM ( but I don't know this for a fact ) gets someone to make their spring components for them. 

 

In fact isn't it the Deaver spring company that makes the springs for Cognito and I assume some other lift companies as on their own website they list leaf and coil springs. Really that is no different than lift companies offering various brands of shocks, they are sourcing parts including all hardware/bolts for a certain lift spec for a model of vehicle and packaging them together as a lift kit and may make a certain unique component that pertains to their brand of lift. 

[kylant]

the cognito bars have the same imprints as the factory bars. I am 100% confident they are a GM made bar. 

you are correct, the more they are cranked, the more stiff they become.

Yes, deaver makes the leafs for Cognito, as well as many other compnies

[GMCnewbie]

6 hours ago, Chuck FB said:

Had you swapped the front shocks at the same time as the front torsion bars, just curious ?. I know you made so many changes to your truck with tire size and so forth but you also did it in some stages so I've forgotten what parts you swapped and then tried before going on to the next swap. Also before you did the torsion bar swap, has you turned the factory keys up or were they still at factory height as I know comments as well as an older truck I had turned keys up on, that certainly stiffens the ride unfortunately. 

Yes, I replaced all of the suspension components.  As part of installing the Cognito bars, I initially tried leaving the stock keys, but the height was off.  I had to install the Cognito keys to see the height gain from swapping to the ZR2 components.  I did not over crank the keys as I didn't want the ride any stiffer than necessary. 

[Chuck FB]

7 minutes ago, GMCnewbie said:

Yes, I replaced all of the suspension components.  As part of installing the Cognito bars, I initially tried leaving the stock keys, but the height was off.  I had to install the Cognito keys to see the height gain from swapping to the ZR2 components.  I did not over crank the keys as I didn't want the ride any stiffer than necessary. 

Yes, I remember you mentioning that now about the discovery that along with the ZR2 components, the factory keys along with the lower rated torsion bars couldn't get your "ZR2 factory" spec height. 

 

When it comes to items like springs or shocks, there is no easy way to evaluate a change in an easy way, its literally by the seat of the pants feel in ride or handling. 

[Chuck FB]

1 hour ago, kylant said:

the cognito bars have the same imprints as the factory bars. I am 100% confident they are a GM made bar. 

you are correct, the more they are cranked, the more stiff they become.

Yes, deaver makes the leafs for Cognito, as well as many other compnies

I wonder where or whom makes the GM bars, if its overseas or within the USA. The reason I ask is that Cognito claims on their website that "their bars" are made in the USA. It does make sense though that because they don't disclose who actually makes the Cognito bars, as some others have said when asking Cognito questions about the bars they seem awfully stupid about knowing anything about the actual rating of the bars as they would know full well where they are sourcing them from and playing that game of exclusivity. I will say that rubs me the wrong way but it is what it is.  

[revrnd]

15 minutes ago, Chuck FB said:

I wonder where or whom makes the GM bars, if its overseas or within the USA. The reason I ask is that Cognito claims on their website that "their bars" are made in the USA. It does make sense though that because they don't disclose who actually makes the Cognito bars, as some others have said when asking Cognito questions about the bars they seem awfully stupid about knowing anything about the actual rating of the bars as they would know full well where they are sourcing them from and playing that game of exclusivity. I will say that rubs me the wrong way but it is what it is.  

 

I dont ever recall where the torsion bars were coming from back in the day.

 

It's interesting to read that the GM & Cognito bars are the 'same'. If GM is sourcing the parts from a vendor, you would think there would be an agreement that the vendor couldn't sell the parts themselves. I know over the years that there are examples of GM owning the tooling, but the vendor uses it in their facilities.

Edited September 17, 2025 by revrnd

[kylant]

18 minutes ago, revrnd said:

 

I dont ever recall where the torsion bars were coming from back in the day.

 

It's interesting to read that the GM & Cognito bars are the 'same'. If GM is sourcing the parts from a vendor, you would think there would be an agreement that the vendor couldn't sell the parts themselves. I know over the years that there are examples of GM owning the tooling, but the vendor uses it in their facilities.

i bet cognito buys them from gm and then upsells them

[revrnd]

17 minutes ago, kylant said:

i bet cognito buys them from gm and then upsells them

Possible. Does anyone know if Cognito paints them a different colour or applies their own decal to them?