Interesting......
My '02 has the Z85 RPO, which one website listed as extra capacity.....whatever that means..???
Replacement springs are rated at 1300 or 1400 lbs....and one website listed the 1300 springs as $10 more than the 1400 springs.....seems odd to me.

Have you made a decision?

 

The spring capacities for the 4-ddor Blazers appear to have come in capacities; 1200 lbs and 1300 lbs. The 1400 lbs ones to me appear to be legitimate GM parts, but I could find with which RPO they are associated.

Roughly speaking the 1,200 lbs was for the softer rides and the 1,300 for the standard rides. The 1,200 lb one was used with the ZW7 that also had the Ninovat self-leveling shocks that could take on some extra weight. This indicates to me that it is likely that the same springs would likely used for different overall suspension types (different RPOs) with the shocks perhaps being the difference between RPO codes that otherwise used the same springs.

With all three listed capacities, there is an inverse correlation to the un-sprung arch height for most of these springs.
22-1015 8.00" 1,200 lbs ZQ1,ZW7
22-1013 7.25" 1,300 lbs Z83, Z85
22-1017 6.88" 1,400 lbs unknown

My current thoughts are that the 22-1017 could be a service replacement for the 22-1013 and if the 22-1013 is a service replacement for the 22-1015.

As for price difference, I've found a wide range of prices for these, so I wouldn't expect any pattern due to capacity.

For you with the Z85, I think it is an extra capacity suspension compared to my ZW7.

And finally, to your question about any decision I will be making: I have a couple inquiries out to ATS and Eaton springs asking for their suggestions. However, I'd be surprised if I hear anything back that will make me not go with the 22-1013 springs from ATS. I can get the springs, 4 u-bolts, and 4 spring bolts for about $340 total. One of the other people who replied said they had good experience with them so that tipped the balance. The prices for the same parts at General Spring was the next best at about $380.

I'll keep you and everyone posted.

 

I see that ATS shows the 22-1013 springs at 1300 lbs for our Blazers. I have found other sites that list both 1300 and 1400 with just "rear, 4wd" as the details. I could not find any info as to OEM spring rating.
I would think there would be a difference in spring rating between a 2 dr 4wd and a 4dr 4wd...???
I have not seen the 1200 lbs ones.
At first thought it seems like the 2dr would use the 1300 and the 4dr the 1400.....or it could be a 2wd uses the 1300 and 4wd uses the 1400 regardless of 2dr or 4dr.

My '02 came with Bilstein shocks...but since I purchased used, no idea if these were stock or previous owner replaced...??? I have not dived into the RPO codes looking for shocks.

I thought my Blazer was sitting lower in rear than front, but a quick measurement at the wheel arch showed rear was higher by 5/8" (same tires/wheels front/rear). But as I stated in my old posting, it does not take much weight for the rear to go down a lot. And after 21yrs...I am sure those rear leafs are weak....probably the torson rods are as well, along with lower control arm bushings.

So...hurry-up and get new leafs on there and let us know the changes.....

 

Alrighty! Update time.

I've placed my order with ATS (https://www.autoandtrucksprings.com/).

Here is why I went with them:

• They make their own springs in their own factories in North America (US, Mex, Can)
• They had the best price
• The guy who interacted with me online by email was super friendly and took my questions seriously
• He confirmed some information I had figured out on my own but did not tell him. This made me trust him.
• I got a good recommendation about them from another BF.com member in this thread.

At the moment, they have a sale with about $20 off per spring (22-1013) and each spring comes with one mounting bolt/nut/washer for free.

I went ahead and got 4 u-bolts and 4 more of the mounting bolt sets. Not including shipping, the total was $288. The shipping across the country was $91.

The only other vender that came close on price and quality, as best as I could perceive, was General Spring. I looked at Rock Auto but the only springs they had were from Dorman and they were on the expensive side. Rock Auto was handy for cross-referencing the specs on the mounting bolts and u-bolts to get.

In the process I've learned a LOT about leaf springs but I never could find what the effective spring rate was for each of the various springs that came on our Blazers. The general impression is that when a spring is specified to have a given capacity, it means that at that load, the ride-height will be where it is supposed to be. However, this is hard to quantify. Believe me, I tried and I'm no slouch with math! There are just too many unknowns.

I've also found myself trying to match up the leaf springs, torsion bars, t-bar keys, and anti-sway bars with each of the suspension types. What I've created (see attached) is incomplete but it is better than nothing. Perhaps I'll go back and try to flesh out the cross reference in the future and submit it as a sticky thread.

Whew!

 

Christine: i thought you might go with the 22-1017 springs since you pull that trailer so much; did ATS advise which to get?
How long will it take for the springs to arrive?
Will you be doing the installation yourself?

 

I didn't know that ATS made their own springs but I am glad to hear your report. Quite a few guys on another board have bought from them and I get a kick out of how far they are being shipped. One or more buyers live in AK and shipping costs must outweigh the price of the merchandise. All I've ever heard is how knowledgeable and helpful they are and have not heard one bad thing about them. I wanted to goose the capacity on my pickup truck by just a little and they gladly added one spring to the standard packet for me.

 

Good questions.

I did not ask about putting in the even larger springs. But my thinking is that these replacements are already a step up in load/spring rate and I didn't want the spring rates between the front and rear to differ by too much. I also have the Nivomat self-adjusting shocks on the back that offset additional load too when needed.

According to the notification I just received, the springs should be getting here on the the 3rd of March, only a week from now. Pretty good since ATS is located back east and I'm in North Idaho.

And yes, I plan on installing them myself. The one anticipated issue will be the removal of the front bolt on the drivers side. The manual calls for removal of the gas tank to have enough clearance to to this. I asked about this in another thread and someone said that they just cut off the bolt and put the new one in from the outside which I'll be doing too. I'm getting all new bolts too since the locking nature of the nuts is by the distortion of the threads. I thought I might as well do the job right. And I'm getting new u-bolts too. For such a critical system, the rear axle, I thought I should install new u-bolts too.

I probably won't get to the installation for at least a month or so. I have have to wait until the snow season is over and after I fix something on my non-snow daily-driver before I can put the Blazer in the garage to replace the springs.

Nivomat shocks: https://www.brakeandfrontend.com/niv...control-units/

 

Well I got the springs. This is pretty fast delivery from all the way across the country.

I haven't had time to check them over. This will have to wait until the weekend. As you can see they ship them bundled with metal straps. According to FedEx, they weigh 75 lbs. They felt like 2x that when I was trying to move them into my front door temporarily. I think I'll undo the straps and move one at a time.

 

Bet your FedEx driver was not real happy handling those springs either.

 

I did think of the poor driver!