ZR-2 leaf swap

[23RST]

I already have the front coilovers & rear shocks. I can get the springs cheap locally.

Question for the real pros out there... are all of the parts in red carryover? Or do I need to also hunt down these ZR2-specific assembly bits?

[silveradosid]

you shouldn't reuse the U bolts the rest is ok

[23RST]

36 minutes ago, silveradosid said:

you shouldn't reuse the U bolts the rest is ok

Just U-bolts?! perfect

any idea what I should search for? OEM? aftermarket?

[newdude]

10 hours ago, 23RST said:

I already have the front coilovers & rear shocks. I can get the springs cheap locally.

Question for the real pros out there... are all of the parts in red carryover? Or do I need to also hunt down these ZR2-specific assembly bits?

 

 

 

What exactly are you working on here?  What "springs locally" are you looking at? 

 

Being you posted in the 2019-2025 1/2 ton section, I can only assume you are working on a 1500?

 

If so, that spring kit you posted doesn't even fit a Silverado/Sierra.  That kit is the long travel kit for a 2018-2022 Colorado ZR2.  

 

 

[23RST]

3 hours ago, newdude said:

 

 

What exactly are you working on here?

23 silverado 1500

 

What "springs locally" are you looking at? 

1500 ZR2 springs

 

Being you posted in the 2019-2025 1/2 ton section, I can only assume you are working on a 1500?

correct

 

If so, that spring kit you posted doesn't even fit a Silverado/Sierra.  That kit is the long travel kit for a 2018-2022 Colorado ZR2.  just a reference

 

 

 

[newdude]

1 hour ago, 23RST said:

 

 

 

The u-bolts are now considered re-usable per GM SI.  

 

As for getting ZR2 springs, I don't think you will get any lift from those if you are looking for the ZR2's height, just different spring rate.  I say this as a Trail Boss to a ZR2 the shocks bolt right in no spring swap for the rear.

 

To get the height you need the rear blocks for Trail Boss/ZR2.  11603207 are the u-bolts, 84379975 are the spring spacers and 84625975 is the jounce stop plate.   

[23RST]

12 minutes ago, newdude said:

 

 

The u-bolts are now considered re-usable per GM SI.  

 

As for getting ZR2 springs, I don't think you will get any lift from those if you are looking for the ZR2's height, just different spring rate.  I say this as a Trail Boss to a ZR2 the shocks bolt right in no spring swap for the rear.

 

To get the height you need the rear blocks for Trail Boss/ZR2.  11603207 are the u-bolts, 84379975 are the spring spacers and 84625975 is the jounce stop plate.   

 

All I want is the ZR-2 leafs, corresponding rear ride height & whatever secondary parts required to do so. Sounds like that's.... nothing? I just re-use everything currently on my RST?

No different brackets, bolts, lift blocks, etc?

Edited May 2, 2025 by 23RST

[newdude]

7 minutes ago, 23RST said:

 

All I want is the ZR-2 leafs, corresponding rear ride height & whatever secondary parts required to do so. Sounds like that's.... nothing? I just re-use everything currently on my RST?

No different brackets, bolts, lift blocks, etc?

 

 

Uh.  No.  

 

You need what I listed.  The longer bolts, the spring blocks, etc.  They gain the height with blocks from the factory.  

 

The ZR2 springs don't add height as far as I can tell.  

 

If you have the mono leaf out back you need everything.  Springs, blocks, rear shackles, u bolts, etc.  

Edited May 2, 2025 by newdude

[23RST]

25 minutes ago, newdude said:

 

 

Uh.  No.  

 

You need what I listed.  The longer bolts, the spring blocks, etc.  They gain the height with blocks from the factory.  

 

The ZR2 springs don't add height as far as I can tell.  

 

If you have the mono leaf out back you need everything.  Springs, blocks, rear shackles, u bolts, etc.  

Got it, thanks!

So,

4x 11603207 u-bolts
2x 84379975 spring spacers

2x 84625975 jounce stop plate

???

Edited May 2, 2025 by 23RST

[newdude]

57 minutes ago, 23RST said:

Got it, thanks!

So,

4x 11603207 u-bolts
2x 84379975 spring spacers

2x 84625975 jounce stop plate

???

 

 

Yes.  I forgot the hardware for the plates.  11602292 x4 and 11602267 x8.  

 

The u bolt nuts you can re-use.  Same with the spring mounting bolts/nuts.   

Edited May 2, 2025 by newdude

[23RST]

23 minutes ago, newdude said:

 

 

Yes.  I forgot the hardware for the plates.  11602292 x4 and 11602267 x8.  

 

The u bolt nuts you can re-use.  Same with the spring mounting bolts/nuts.   

 

you're the man! thank you

[GETGONE]

12 hours ago, silveradosid said:

you shouldn't reuse the U bolts the rest is ok

I REALLY wish you'd stop posting old school WRONG information.

[GETGONE]

The ZR2 leaf springs have a softer spring rate to match with the DSSV dampeners. You will lose some towing and payload capacity. Check the differences on GM's site of an RST vs ZR2 towing and load capacities. There is no lift with the ZR2 springs. I think the block is a 2.5" vs 2" on the Trail Boss.

[newdude]

2 hours ago, GETGONE said:

The ZR2 leaf springs have a softer spring rate to match with the DSSV dampeners. You will lose some towing and payload capacity. Check the differences on GM's site of an RST vs ZR2 towing and load capacities. There is no lift with the ZR2 springs. I think the block is a 2.5" vs 2" on the Trail Boss.

 

 

ZR2 and Trail Boss use the same p/n block.  

[GETGONE]

4 hours ago, newdude said:

 

 

ZR2 and Trail Boss use the same p/n block.  

OK. It was my understanding it was slightly larger to gain the extra .5" lift in the rear.