Zr2 front suspension

[GMCnewbie]

1 hour ago, GATORB8 said:

Cognito is saying their Comfort Ride Torsion Bars wont work on the ZR2.

Really?  I just emailed Cognito last week asking for recommendations on shocks.  Told them I was about to convert my GMC 2500 AT4 suspension to the ZR2/AT4X parts and switch to their torsion bars and leaf springs.  They didn't say anything about the setup other than. To recommend their Elite 3" lift kit with the 2.5" shocks.  This will be very disappointing if you're correct.

[GATORB8]

3 hours ago, GMCnewbie said:

Really?  I just emailed Cognito last week asking for recommendations on shocks.  Told them I was about to convert my GMC 2500 AT4 suspension to the ZR2/AT4X parts and switch to their torsion bars and leaf springs.  They didn't say anything about the setup other than. To recommend their Elite 3" lift kit with the 2.5" shocks.  This will be very disappointing if you're correct.

To be fair, I chatted them, but I waited 15 minutes to be connected so I assumed it was one of the cognito guys.

 

Only thing I can think is that a different location in the LCAs require a different length that would even matter.

Edited October 9, 2024 by GATORB8

[GMCnewbie]

37 minutes ago, GATORB8 said:

Only thing I can think is that a different location in the LCAs require a different length that would even matter.

That would make sense.  Guess I need to hit them up again tomorrow as I want to start ordering GM parts before the 35% discount expires at the end of the month.  Appreciate the heads up.

[GATORB8]

46 minutes ago, GMCnewbie said:

That would make sense.  Guess I need to hit them up again tomorrow as I want to start ordering GM parts before the 35% discount expires at the end of the month.  Appreciate the heads up.

Let me know what you hear.

[revrnd]

On 4/18/2024 at 10:08 PM, Epsilon Plus said:

The ZR2 transfer case skid vs the baby Z71 skid. In the process of drilling the rear holes. Going to use through+bolts and nuts. Initially was going to tap M10x1.5 threads for one of the unused front Z71 bolts and add another, but didn't have the right 8.5mm or whatever PITA metric bit.

 

Fits on the 20-23 great, just need to drill rear holes.

 

 

Any particular placement of the skidplate/ From the after photo it appears that the plate is positioned rearward so the the forward bolts are @ the front of the slots.

[GMCnewbie]

17 hours ago, GATORB8 said:

Let me know what you hear.

So... I just got the following response from Cognito:

 

"the AT4X/Zr2 2500 doesn't share components with the the AT4/Trailboss trims. Wherein we only have a super stock package that only adds droop travel."

 

This is incredibly disappointing to learn, but I'm left very confused.  The main differences between the AT4 and AT4X (ZR2) are different knuckles, upper and lower control arms, and the rear leaf spacers.  The torsion bars aren't removed or even moved as far as I know.  So why wouldn't the Cognito bars work?  I guess I'll look at the torsion bars for both the AT4 and AT4X to see if there are any differences there.  I naturally assumed they were the same.  I say that because there's a thread on another GM forum for HD trucks where several guys have made the switch to the other parts and I don't recall anyone calling out the torsion bars as an issue.

[GATORB8]

9 minutes ago, GMCnewbie said:

So... I just got the following response from Cognito:

 

"the AT4X/Zr2 2500 doesn't share components with the the AT4/Trailboss trims. Wherein we only have a super stock package that only adds droop travel."

 

This is incredibly disappointing to learn, but I'm left very confused.  The main differences between the AT4 and AT4X (ZR2) are different knuckles, upper and lower control arms, and the rear leaf spacers.  The torsion bars aren't removed or even moved as far as I know.  So why wouldn't the Cognito bars work?  I guess I'll look at the torsion bars for both the AT4 and AT4X to see if there are any differences there.  I naturally assumed they were the same.  I say that because there's a thread on another GM forum for HD trucks where several guys have made the switch to the other parts and I don't recall anyone calling out the torsion bars as an issue.

Is the front LCA insertion location moved, maybe?

[GMCnewbie]

Not sure as I don't have the other parts in hand.  But I'd imagine anyone doing this change would then need to purchase new torsion bars as well.  That could be the case, but I don't recall seeing that mentioned anywhere.

[Epsilon Plus]

Sounds like social media kid or intern horsecrap. There's no difference in bar length or position from any trim 2500 or 3500. The only thing different is the spring rate within the bar.

 

As far as the transfer case skid goes, it mounts to the same front holes although ZR2 uses two of the three bolts from Z71. The skid lays against the curved rear crossmember form-fit style. The 2024+ trucks MIGHT have the rear skid holes predrilled/tapped just like all 4x4s have the Z71 skid holes predrilled/tapped. Someone with a 24+ has yet to comment on whether they are there or not. 

[revrnd]

13 minutes ago, Epsilon Plus said:

Sounds like social media kid or intern horsecrap. There's no difference in bar length or position from any trim 2500 or 3500. The only thing different is the spring rate within the bar.

 

As far as the transfer case skid goes, it mounts to the same front holes although ZR2 uses two of the three bolts from Z71. The skid lays against the curved rear crossmember form-fit style. The 2024+ trucks MIGHT have the rear skid holes predrilled/tapped just like all 4x4s have the Z71 skid holes predrilled/tapped. Someone with a 24+ has yet to comment on whether they are there or not. 

As seen under my 2024 from the driver's side.

 

LH hole is flush, RH hole is in a 'dimple'. Hole spacing is approx' 12" apart.

 

The LH hole doesn't appear to be tapped. I'll check the dia' tomorrow (dark & cooling off here LOL)

Edited October 9, 2024 by revrnd

[GMCnewbie]

1 hour ago, Epsilon Plus said:

There's no difference in bar length or position from any trim 2500 or 3500. The only thing different is the spring rate within the bar.

Thanks!  That's what I was assuming.  Couldn't imagine GM would go off script with the heavy duties for a single trim package.  Ok... time for me to start ordering parts!  Most likely won't do the install until late Feb or early March (bonus time) when I can order new wheels and tires.  But I want to take advantage of the GM discount on suspension parts this month including free shipping to the local stealership. 

[GMCnewbie]

Just placed my parts order with GM.  Saved a bunch on shipping by having the parts shipped to the stealership.  Found several discount GM parts stores online that offered the parts a few dollars cheaper, but added $500 for shipping on the back end.  In the end, my total price for all parts (UCA, LCA, knuckles, differential brackets, spacers, bolts, and nuts) was $989 after all the discounts (35% for suspension parts, 15% for the differential brackets, and almost $300 in GM rewards).  I'm excited.  Parts should show up over the next 2 weeks.

 

On the ropes with the Cognito Comfort Ride torsion bars and leaf springs.  I'll keep an eye out for any Black Friday deals for these.  

 

Also need to order new shocks.  Shock Surplus recommends the Fox 2.5 Performance HTO shocks.  I need to look into these to see how they compare with the Fox 2.0 shocks.  I had the 2.0 shocks on my Ram and it certainly improved the ride quality, but I felt like the truck floated a bit at highway speeds.  Cornering seemed to take a hit with the 2.0's.  If these 2.5 HTO shocks improve on that, I'm in.  Otherwise, I'll look at other options.

[revrnd]

On 1/11/2024 at 9:11 AM, Joe97281 said:

Front skid arrived. Takes 5 minutes to change with a 15mm socket and needle nose pliers. Pliers are needed to get the keeper off the two rear engine shield bolts. 

 

It sits lower than the stock steel piece (to allow for diff drop). 

 

Oversize shipping made it the same price online and shipped as ordering to local dealer. 

Are the keepers like Tinnerman clips? 

[OS RR]

How tall is the rear lift block? 1.5"?

[Epsilon Plus]

On 1/6/2025 at 6:59 PM, OS RR said:

How tall is the rear lift block? 1.5"?

 

Yes. This necessitates the use of 3500 U-Bolts. The only other ZR2 part in the rear besides shocks is a plastic jounce bumper extension that slips over the stock pad and clips in on it's own.