Lets Talk Z60 Suspension

[Texasdeere]

I bought this truck used back in March.  Didn't really notice how rough the ride was until I had it a while.  I recently had the local parts department print me out a

RPO List using my VIN and I now see what I thought was a tire problem is actually suspension.  The current suspension is completely stock, no lift or level. 

Unless I am on smooth asphalt this is the worst riding truck I have ever owned. (including 3/4 and 1 Tons)

 

So from what I have been able to research on the Z60 option, The front stabilizer bar is a little bigger.  Either both the Front and Rear Shocks are different or maybe just the fronts, not completely sure.  And the big mystery is the Strut Springs and Rear Leaf Springs?  Any Ideas on the Spring differences?

 

I don't think the sway bar really makes a noticeable difference in ride harshness on the street.  I think different Shocks will help but I think I may have to change the springs out too. 

 

I would like to convert the truck to Z83 Springs and Shocks.  I believe even Z71 suspension without the Ranchos would be an improvement.

 

I know the obvious answer is to go to the Dealer and I agree.  But I am trying to avoid that mainly for cost.

 

I'm going to get under the truck and get some spring part #'s and post them next.  At least the Rear Leafs

 

 

GM 2012 Press Release

 

 Sierra is offered with five suspension systems, each tailored to suit specific driving requirements:

 

Z83 – Delivers a solid, smooth ride with monotube front shocks and twin-tube rear shocks

Z85 – Designed for enhanced handling and trailer towing, with monotube front and rear shocks

Z71 – Delivers enhanced off-road capability; features specific monotube front and rear shocks

Z60 – Designed for maximum street performance and offered with 20-inch wheels, as well as monotube front and rear shocks

NHT – Designed for maximum towing capacity; it includes monotube rear shocks, 17-inch wheels and off-road tires, and high-capacity rear springs.

 

 

[Z45]

Z60 is standard Denail Suspension and I had 2 Sierra's with the Z60 and they rode good. better than a Z71 IMHO which I had occasion to drive frequently.

[Texasdeere]

I know it comes standard on SLT and Denali which really surprised me.  My 2019 T1 LTZ rode super cush but too bouncy for sure.  I had Bilsteins planed for it but sold the truck first.

[Texasdeere]

Rear Leafs 23208339

 

Rear Shocks 23106631

 

Front Springs 22826290

 

Front Shocks 23106620

 

Part numbers don't say anything special or specific.  The front Shock # doesn't come up.

[Texasdeere]

I believe I have found a reasonable solution for my truck.

 

KYB makes an OEM style stock replacement kit for theses trucks SR4545 Spring and Shock assembled Kits for the front and 345074 Shocks for the rear.  They are very well priced, under $500 shipped from Rockauto.  This should be very comparable to the stock Z83 or Z85 set up.

 

If the front end still seems harsh I will remove the Z60 36mm front sway bar and replace it with a Z83 32mm bar.

 

That only leaves the original rear leaf springs.

 

I will update afterwards

 

 

[UrbanRage]

What size rims do you have? I'm asking because my truck has the factory 20-inch rims, while my buddy's truck has 18-inch rims. The difference in ride quality between the two is noticeable.

[newdude]

On 10/11/2023 at 12:55 PM, Texasdeere said:

I bought this truck used back in March.  Didn't really notice how rough the ride was until I had it a while.  I recently had the local parts department print me out a

RPO List using my VIN and I now see what I thought was a tire problem is actually suspension.  The current suspension is completely stock, no lift or level. 

Unless I am on smooth asphalt this is the worst riding truck I have ever owned. (including 3/4 and 1 Tons)

 

So from what I have been able to research on the Z60 option, The front stabilizer bar is a little bigger.  Either both the Front and Rear Shocks are different or maybe just the fronts, not completely sure.  And the big mystery is the Strut Springs and Rear Leaf Springs?  Any Ideas on the Spring differences?

 

I don't think the sway bar really makes a noticeable difference in ride harshness on the street.  I think different Shocks will help but I think I may have to change the springs out too. 

 

I would like to convert the truck to Z83 Springs and Shocks.  I believe even Z71 suspension without the Ranchos would be an improvement.

 

I know the obvious answer is to go to the Dealer and I agree.  But I am trying to avoid that mainly for cost.

 

I'm going to get under the truck and get some spring part #'s and post them next.  At least the Rear Leafs

 

 

GM 2012 Press Release

 

 Sierra is offered with five suspension systems, each tailored to suit specific driving requirements:

 

Z83 – Delivers a solid, smooth ride with monotube front shocks and twin-tube rear shocks

Z85 – Designed for enhanced handling and trailer towing, with monotube front and rear shocks

Z71 – Delivers enhanced off-road capability; features specific monotube front and rear shocks

Z60 – Designed for maximum street performance and offered with 20-inch wheels, as well as monotube front and rear shocks

NHT – Designed for maximum towing capacity; it includes monotube rear shocks, 17-inch wheels and off-road tires, and high-capacity rear springs.

 

 

 

21 hours ago, Texasdeere said:

I believe I have found a reasonable solution for my truck.

 

KYB makes an OEM style stock replacement kit for theses trucks SR4545 Spring and Shock assembled Kits for the front and 345074 Shocks for the rear.  They are very well priced, under $500 shipped from Rockauto.  This should be very comparable to the stock Z83 or Z85 set up.

 

If the front end still seems harsh I will remove the Z60 36mm front sway bar and replace it with a Z83 32mm bar.

 

That only leaves the original rear leaf springs.

 

I will update afterwards

 

 

 

 

 

Just to clarify here a bit.  K2XX (2014-2019 generation) never used "Z83" suspension.  They used Z85, Z71, NHT and Z60. 

 

Z83 was on the GMT-900 2007-2013.

 

That said.  If it were still available, a Z83 sway bar would fit a K2 truck as the frames are rather identical between the two generations.  The suspension (shocks and struts) likely would fit too.

 

As for the sway bars....

 

32mm and 34mm bars are both replaced by a 36mm bar for 07-13 generation, p/n 23498331 and fits every suspension code 07-13 except for hybrids.  

 

23498331 is also the bar used 2014-2019 for NHT max trailer and ZW9 box delete.  

 

The other bar they still have is 22758132 and its a 34mm bar.  This would be for a Z85, Z71 and Z60 trucks for 2014-2019.    

 

I have verified this info with multiple VINs of GM trucks to see what bar they spec for what suspensions.  

 

Dorman appears to be the only aftermarket OE replacement bar and they make a one size fits all bar.  

 

 

[Texasdeere]

Thanks Guys, 

 

My truck does have the 20's on it.  I played around with the tire pressures without much difference in ride.

I ran them down to 29 psi for a few days from my normal 38 and 35.

 

I noticed in my research the Suspension codes for the GMT900 trucks had different component packaging than the later trucks.  A big one was a lower ride height with the Z60 package.  Doesn't seem to be the case with the later K2XX trucks.  I hadn't noticed that there was no Z83 for the K2XX trucks.

 

I went on an ordered the KYB stuff yesterday.  It was just under $600 for the front and rear.  I will be installing everything early next month when I am off from work again.

 

[Texasdeere]

Well I got everything installed and it was super easy.  I was expecting at the very least some noticeable improvement over the factory stuff but the truck still feels about the same. "Mega Stiff" It literally rides worse than a New 2500HD Sierra.  Or any other HD truck that I have ever owned or rode in, including 1-tons and that's a lot.  What's funny my 2019 1500 rode very different.  It had the factory 20's and actually rode very nice.  It did have too much bounce, like going over a speed bump slowly.  Something shocks would have probably fixed. 

 

The front of the truck raised up 2.0" initially and back down to 1.5" after settling which is good. Quality seems very good.  But I can not recommend these as a fix or improvement for the Z60 set up for the few that don't like the Z60 Suspension.

 

My truck called for the SR4546 Struts. The SR4545 for the Reg Cab might have been better.  Or 2019 T1 Front Struts!

 

Maybe when the Continental Tires come off there will be some improvement?  I don't know.

[asilverblazer]

Have you changed out the rear shocks? Has one of them seized?

[Texasdeere]

I did replace all 4 corners with KYB's  Just shocks in the back.

 

I have noticed, or it seems from various pictures I have seen the 1/2 ton GMT900's and T1's they seem to have 5 coils on the front springs not 7 like mine.  Not sure if this is really the case. 

 

As long as I can stay away from modern new concrete roads or old asphalt ones I am good.  I might need to move to Florida.

[ryan35205]

Did the KYBs keep it the same height in the front? I was concerned that pre-assembled assembly would raise it up an inch to standard non-z60 height.. I guess which it would make the rake 1 inch instead of 2 inches.