2012 Suburban 1500 - new front springs with more capacity - ZW7 suspension

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

russellbailey

TYF Newbie
Joined
Aug 19, 2019
Posts
6
Reaction score
6
I have a 2012 Suburban 1500 4wd LS at 150k miles. I load it heavily - I've pulled a 7500 lb trailer probably 20k miles (boat, to coast and back) as well as sometimes put a couple hundred pounds on the front hitch (bicycles).

At maybe 40k miles I replaced the rear coil springs with Hellwig airbags completely, and I can adjust that pressure from the cab depending on load - the stock springs really struggled with the 700 lb tongue weight even with a weight distributing hitch. I also have Bilstein 4600s plus the Hellwig 3-position swaybar on the stiffest setting. The rear works great.

The front is soft, and I want to replace the springs when I replace the current 4600. I understand that the Z71 may have come with a slightly stiffer front spring to get the increased ride height, and I'm interested in more details about that. I'd be fine with the height coming up 1-2" to level, but I'm really looking for a slightly stiffer spring without getting harsh.

I looked up Moog spring options and found 3. Moog part #s are
81246
81248
81250

Here are the specs I see for each after emailing with a vendor - interestingly his spec only showed these as being valid through 2010.
spring bar dia spring rate free height design load ID OD
81246 0.781" 567 lb/" 14.297" 2720 lb 4.640" 6.200"
81248 0.781" 567 lb/" 13.634" 2344 lb 4.640" 6.200"
81250 0.765" 580 lb/" 14.51" 2906 lb 4.570 6.110"

All are constant rate. I presume these are likely OEM equivalents but with different part #s.

Does anyone know if one of these equates to the spring that I have on now? As well, does anyone know which one equates to the Z71 spring?

When I see Z71 Suburbans, it appears that the stock suspension has more ride height in the front, which I presume comes via being slightly more stiffly sprung.

My guess is that 81246 is equal to my current spring, and 81250 is equal to the Z71 front spring. If I can confirm that, I'm likely going to replace the springs as well as the shock/strut soon on the front and go with that slightly stiffer spring.

Thank you for your input. I've had difficulty finding this level of detail on the internet searching around.
 

Doubeleive

Wes
Supporting Member
Joined
Nov 7, 2017
Posts
23,420
Reaction score
34,048
Location
Stockton, Ca.
might be because of the suspension system in general, like if the 2010's use a leaf spring in back and if the 2012 does not. my 2012 use's struts in the front. look on rockauto for more heavy duty front struts they have it broke down into sections
 

swathdiver

Full Access Member
Joined
May 18, 2017
Posts
19,104
Reaction score
25,037
Location
Treasure Coast, Florida
I have a 2012 Suburban 1500 4wd LS at 150k miles. I load it heavily - I've pulled a 7500 lb trailer probably 20k miles (boat, to coast and back) as well as sometimes put a couple hundred pounds on the front hitch (bicycles).

At maybe 40k miles I replaced the rear coil springs with Hellwig airbags completely, and I can adjust that pressure from the cab depending on load - the stock springs really struggled with the 700 lb tongue weight even with a weight distributing hitch. I also have Bilstein 4600s plus the Hellwig 3-position swaybar on the stiffest setting. The rear works great.

The front is soft, and I want to replace the springs when I replace the current 4600. I understand that the Z71 may have come with a slightly stiffer front spring to get the increased ride height, and I'm interested in more details about that. I'd be fine with the height coming up 1-2" to level, but I'm really looking for a slightly stiffer spring without getting harsh.

I looked up Moog spring options and found 3. Moog part #s are
81246
81248
81250

Here are the specs I see for each after emailing with a vendor - interestingly his spec only showed these as being valid through 2010.
spring bar dia spring rate free height design load ID OD
81246 0.781" 567 lb/" 14.297" 2720 lb 4.640" 6.200"
81248 0.781" 567 lb/" 13.634" 2344 lb 4.640" 6.200"
81250 0.765" 580 lb/" 14.51" 2906 lb 4.570 6.110"

All are constant rate. I presume these are likely OEM equivalents but with different part #s.

Does anyone know if one of these equates to the spring that I have on now? As well, does anyone know which one equates to the Z71 spring?

When I see Z71 Suburbans, it appears that the stock suspension has more ride height in the front, which I presume comes via being slightly more stiffly sprung.

My guess is that 81246 is equal to my current spring, and 81250 is equal to the Z71 front spring. If I can confirm that, I'm likely going to replace the springs as well as the shock/strut soon on the front and go with that slightly stiffer spring.

Thank you for your input. I've had difficulty finding this level of detail on the internet searching around.


Welcome to the forum Russell. A couple of years ago I attempted to find the same information but came up with zip. It's not like the old days when Moog and Monroe had specs galore in their catalogs. There's no difference in a plain jane ZW7 suspension from 2009-2014 and maybe even earlier with the 4-speed trucks.

Your second sentence raised some eyebrows with me, I've had a lot of tongue weight on my hitch (about 1100 pounds) and had no such sagging and didn't even have Air Lift Springs installed in them.

Z71 springs would be a little more stiff. Of all the GMT900 offerings, the Escalade EXT and Avalanches have a 3800 pound rating for their front axle, 200 more than ours. All of them, every year. Might want to grab a VIN from one and plug it in at the AC Delco website and see what they use.

https://parts-catalog.acdelco.com/catalog/catalog_search.php


My front springs are 25876861/45H0427 and the rear springs are 25783733/45H2164.
 

swathdiver

Full Access Member
Joined
May 18, 2017
Posts
19,104
Reaction score
25,037
Location
Treasure Coast, Florida
Weird. I plugged in some 2011+ EXT and Avalanche VINs on ACDelco's website and got nothing. Then used a 2010 VIN and got the same options as mine.

45H0426 are listed as Heavy Duty front springs while the rear HD springs are the same as mine, 45H2164. Interesting.

Now if we could only find the specs on these here GM springs! I gave up years ago but maybe you're on to something with that info you have.

Ok, That front HD spring crosses over to a Moog 81244 on this website: https://www.mw-ind.com/distributor-tools-pontotoc-part-number-interchange/
 
OP
OP
R

russellbailey

TYF Newbie
Joined
Aug 19, 2019
Posts
6
Reaction score
6
Thanks swathdiver - appreciate your input. I’ve not given up on spring data yet and have some inquiries out. The 2011+ lack of cross references is curious.

To be fair, the car handled 700 lbs ok, but it was really soft and compressed a lot over bumps and in sharp mountain turns - it was controllable but had a lot of motion. It may have been the premium smooth ride springs were just too soft. I found it choppy empty and mushy loaded - now with the Hellwigs it is excellent all the time.
 

avalonandl

Full Access Member
Joined
Apr 6, 2019
Posts
2,200
Reaction score
2,628
Location
Troy, MICH & Naples, FL
I have ordered the Timbrens kit to install. I recently replaced my air compressor for my auto ride. But I will be towing a 35 ft center console (9500 lbs incl trailer) about 35 miles to the storage yard.IMG_2326 small.jpg
 
OP
OP
R

russellbailey

TYF Newbie
Joined
Aug 19, 2019
Posts
6
Reaction score
6
I have ordered the Timbrens kit to install. I recently replaced my air compressor for my auto ride. But I will be towing a 35 ft center console (9500 lbs incl trailer) about 35 miles to the storage yard.View attachment 229068

Are you installing Timbrens on the front? I have a pair but have not installed them yet.

I can't recommend the Hellwig kit for the rear enough - so much better than the coils to maintain ride quality as you load it down. I also have Supersprings in my rear bump stops but they basically never touch since I can balance out anything with the Hellwig bags - I've never gone above 70 psi in them and you can go to 100 psi. Unloaded I keep them at about 45 psi.
 
OP
OP
R

russellbailey

TYF Newbie
Joined
Aug 19, 2019
Posts
6
Reaction score
6
Weird. I plugged in some 2011+ EXT and Avalanche VINs on ACDelco's website and got nothing. Then used a 2010 VIN and got the same options as mine.

45H0426 are listed as Heavy Duty front springs while the rear HD springs are the same as mine, 45H2164. Interesting.

Now if we could only find the specs on these here GM springs! I gave up years ago but maybe you're on to something with that info you have.

Ok, That front HD spring crosses over to a Moog 81244 on this website: https://www.mw-ind.com/distributor-tools-pontotoc-part-number-interchange/
Well, 2 years later, I finally picked a spring.

I considered Moog 81244 which as you noted is also cross referenced as the front HD spring. I also considered 81250, and the Dayton CargoMaxx.

The shop that installed for me tested the 3 springs out compared to the OEM spring. My aim was 15-20% stiffer, and 2-3” ride height increase. The ride height increase was secondary - I wanted more capacity.

The qualitative order of stiffness was OEM, 81250, 81244, and CargoMaxx. They compared deflection with a lever and a weight, and suggested going with 81244.

So far so good. I used Bilstein 5100 on 1 ring up from lowest (about 0.75”). Between the 81244 springs and the 0.75” Bilstein lift, my front bumper is now 3.75” higher than it was with the OEM springs. I don’t know if my OEM springs sagged over time or what, but that is big difference. The car sits much more level now, and hitting bumps it feels like there is much more capacity to absorb bumps than previously.

The CargoMaxx may have been ok, but I think it is probably too stiff without something like a plow on regularly. The CargoMaxx are for sale if anyone is interested in messing with them.

Based on my experience, I fully recommend the Moog 81244 together with Bilstein 5100 on the 1st ring up.
 
Top