AAL vs 3/4t Springs?

[boy&hisdogs]

I'm looking to get 1-2 inches of lift in the rear of my k1500. This would be in addition to a 4" shackle flip and 6" Zone lift in the front. The zone lift comes with a 5" block so the extra 1-2 inches from an AAL or 3/4t spring would put the rear closer to where it's supposed to be with the lift kit.

Currently my truck is stock, and several years ago I cranked the front maybe 1/2" to 1" above level. I have since added a lumber rack and a full toolbox and right now the truck sits 2" low in the back.

I think that with the added weight a little bit stiffer spring rate would be welcome. I was thinking either an add-a-leaf or a 7200# (light 2500) spring pack.

The general interwebs knowledge says that either one will lift the truck about the same amount, and the AAL would be easier since I can just order them new instead of having to hunt for them in the junkyard, but is there any difference between the two in terms of ride, stability, performance, etc?

 

[stutaeng]

I would say the 3/4 ton leaf springs.

I ran an AAL on one of my GMT 800 1500 and was not thrilled about it. They rattled too much. Mine came with a little metal strap you just bend to hold the extra leaf in there. Over time that strap wondered around... They also rode pretty harsh, but don't know how it compared to 3/4 ton leafs.

Coinsidently, I'm planning on swapping some 3/4 ton leafs on that same truck, lol.

 

[alpinecrick]

Installing the 2250 lb light duty 2500 springs on my '96 K1500 was one of the better upgrades I've done. The original 1/3 springs would were sagging a bit and would squat with any kind of load. If anything it improved handling, and the ride turned out to be surprisingly good. Very little increase in harshness. It lifted the rear 1-1.5".

I liked the springs so much I immediately ordered a pair for my '97 K1500. One of these days I might even get around to installing them.........

 

[boy&hisdogs]

I would say the 3/4 ton leaf springs.

I ran an AAL on one of my GMT 800 1500 and was not thrilled about it. They rattled too much. Mine came with a little metal strap you just bend to hold the extra leaf in there. Over time that strap wondered around... They also rode pretty harsh, but don't know how it compared to 3/4 ton leafs.

Coinsidently, I'm planning on swapping some 3/4 ton leafs on that same truck, lol.

That says it all right there!

Installing the 2250 lb light duty 2500 springs on my '96 K1500 was one of the better upgrades I've done. The original 1/3 springs would were sagging a bit and would squat with any kind of load. If anything it improved handling, and the ride turned out to be surprisingly good. Very little increase in harshness. It lifted the rear 1-1.5".

I liked the springs so much I immediately ordered a pair for my '97 K1500. One of these days I might even get around to installing them.........

My dad has an 05 2500HD that is 9200# GVWR and there is definately a noticeable difference in harshness there. I've never ridden in a "heavy half" or LD 2500 but with the added weight of my rack and toolbox and the fact that I'm getting new Bilstien shocks at the same time makes me think that the light 2500 springs won't be so bad.

Did you order them new?

 

[stutaeng]

That says it all right there!



My dad has an 05 2500HD that is 9200# GVWR and there is definately a noticeable difference in harshness there. I've never ridden in a "heavy half" or LD 2500 but with the added weight of my rack and toolbox and the fact that I'm getting new Bilstien shocks at the same time makes me think that the light 2500 springs won't be so bad.

Did you order them new?

I was going to order them new (about $175 each IIRC,) but then I realized the 1500/2500/3500 on those trucks seem like they all have the same fit. So I found some used ones from a 2500HD for $50. I don't know if the 2500LD have lower spring rate than the 2500HD...will pick them up today. I do expect the truck to ride rougher. I plan to install one of those shells on the bed in the future, maybe that will help some. It's a 2wd with those lifting knuckles in the front and a block on the rear, which truly "leveled" it. I'm personally not a fan of the that look. I prefer a factory rake or at least a small amount of rake. On my truck 3 bags of playsand in the bed had me doing the California lean!...not acceptable in my book, LOL.

 

[PlayingWithTBI]

I'm going the other way with my C1500. I have 4/1 leafs now and it rides like a truck, LOL! I ordered 3/1s to get the stink bug look cured. If it sags with a load I plan on getting air shocks or bags. You want a pair of 4/1s, come and get 'em. I hope to do the swap next weekend if I get the springs and hardware by then. I already have the U-Bolts.

 

[stutaeng]

I'm going the other way with my C1500. I have 4/1 leafs now and it rides like a truck, LOL! I ordered 3/1s to get the stink bug look cured. If it sags with a load I plan on getting air shocks or bags. You want a pair of 4/1s, come and get 'em. I hope to do the swap next weekend if I get the springs and hardware by then. I already have the U-Bolts.

5 leaf pack on a RCSB 1500? That's stock? You've got a 9.5" 14 bolt also, right? My brother's '90 and Dad's '88 C1500 RCSB have a 4 leafpack. All of the 1500 GMT400 trucks I've seen have a 4 leafpack.

 

[PlayingWithTBI]

5 leaf pack on a RCSB 1500? That's stock? You've got a 9.5" 14 bolt also, right?

No, it's a 10 bolt. FWIU they call it a "heavy 1/2" but, in this case the PO installed them and had to use 7" shackles to get it so the rear is 2" higher than the front. I don't know where he got these springs but they have a higher arc than what I've been able to find for normal replacement springs.

 

[stutaeng]

No, it's a 10 bolt. FWIU they call it a "heavy 1/2" but, in this case the PO installed them and had to use 7" shackles to get it so the rear is 2" higher than the front. I don't know where he got these springs but they have a higher arc than what I've been able to find for normal replacement springs.

Are they perhaps from a 2500LD the OP was talking about then? Note he said those will lift the rear the same as the AAL. I believe those came with the 14 bolt with the 2500 6 lug trucks. Or they aftermarket?

I honestly don't really know what the "heavy half" is on the GMT400, but sounds like it's the same as the 2500LD? I'm always confused on those trucks, LOL.

 

[PlayingWithTBI]

Are they perhaps from a 2500LD the OP was talking about then? Note he said those will lift the rear the same as the AAL. I believe those came with the 14 bolt with the 2500 6 lug trucks. Or they aftermarket?

IDK where he got them. Looking at a spring website, they offer the same 4/1 pack for C/K1500s and 2500s -
Who knows what evil lurks in the minds of GM engineers - the Shadow does!