Does anyone make stiffer springs??

l008com

Original poster
Member
Feb 19, 2016
886
Massachusetts
My Trailblazer drives like a boat. It has what I'd call a very floaty, "luxurious" ride. I put new shocks on and new tires, and both helped, but it's still way too soft for my liking. I really liked the stiff, sporty ride of my old ZR2 Blazers (S10).

I've been searching and searching for spring upgrades for trailblazers. And the ONLY spring "upgrades" i can find are lowering springs. Doesn't ANYONE make stiffer springs that do not change the ride height? I don't want to lower, I don't want to lift. Stock height is just fine by me, and my big 275 tires just fit, no need to mess with that.

I also want to upgrade to stiffer swaybars at some point. But those seem much easier to find than stiffer springs.
 

gmcman

Member
Dec 12, 2011
4,656
Bilstein HD works pretty good. There may be stiffer shocks and strut cartridges but may get $$$.
 

Matt

Member
Dec 2, 2011
4,019
Not sure if they'll work for you but the Moog 81069 springs are stiffer...but they're for Tahoe's etc.
 

littleblazer

Member
Jul 6, 2014
9,265
You can use ext front coils but that'll lift iirc. I don't believe there are upgrades that won't unless you find maybe an oem set of ss front coils? And even then I think they're lower but stiffer.
 

Sparky

Member
Dec 4, 2011
12,927
What shocks did you get out of curiosity?

No one made stiffer springs just for stiffer's sake. GM had a bunch of different springs for these depending on options and some are stiffer than others, but they would affect resting height a bit. Enough to make a difference? I don't think it would be much but I can't say for sure. It would depend on which springs yours had to start with.

Moog replacement springs are a bit higher on the stiffness scale but not sure how much compared to your existing springs.
 

l008com

Original poster
Member
Feb 19, 2016
886
Massachusetts
What shocks did you get out of curiosity?

I got the bilstein HDs. They don't really feel stiff to me at all. But it's all relative I suppose, and my previous vehicles are 5th gen camaros, RX8s, and ZR2 Blazers. All very stiff riding vehicles. Even with those shocks, my trailblazer feels like it floats around the road.

Bilstein HD works pretty good. There may be stiffer shocks and strut cartridges but may get $$$.
I already have those, i need stiffer springs not stiffer shocks

You can use ext front coils but that'll lift iirc.
Just front, not front and rear?
 
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l008com

Original poster
Member
Feb 19, 2016
886
Massachusetts
SS springs drop an inch or so, right? But are much stiffer? Do they make spring spacers? SS springs +1" spacer, so I'll get factoryish ride height but sportier ride I want?
 

littleblazer

Member
Jul 6, 2014
9,265
I don't remember off the top of my head... I do believe the ss sits lower stock so whatever the difference is. I couldn't personally say how much stiffer the spring is because I've never been in. An ss but it is stiffer.
 

l008com

Original poster
Member
Feb 19, 2016
886
Massachusetts
Those 2" rear drop springs that I keep reading about on forums, are those stiffer than normal rear springs? I'm not sure I really want to drop the rear though. Leveling sounds nice but I also tow a lot and carry heavy loads a lot, and I don't want the back to be dragging when I do. And I definitely don't want to install a stupid air bag system. No way, gotta keep it nice and simple.

Maybe OEM moog rear springs, and OEM SS front springs, with some kind of 1" spring spacer in the front?
 

l008com

Original poster
Member
Feb 19, 2016
886
Massachusetts
Does anyone know for sure if EXT springs will life a SWB truck? Would they just bolt up like normal front and rear? Or are the rear suspensions different on the EXTs? I know I read somewhere that the EXTs had a totally different frame than the SWBs. If I had to choose between and inch lift and inch drop, I'll probably go with EXTs and get an inch lift... of course I just made that up and I have no idea what the real result of EXT springs would be.
 

Harpo

Member
Dec 4, 2011
411
Sweden
I doubt that you will see any noticeable lift with EXT Springs in the front, if you do it will only take some of the rake away.
Imo it will not give you the stiffness your after. To possibly the achieve what I think your after your might try to get the stiffest lowering springs you can find an top that off with a liftkit that will keep the stock height. Just an idea,sound expensive though.

I agree on the Bilsteins, i also thought I would get a firmer ride when I put those on,no dice.
I think they are almost like the oem,they are for sure better quality but the difference is hardly noticeable. Maybe if your oem was really bad,mine wasn't obviously.
 
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l008com

Original poster
Member
Feb 19, 2016
886
Massachusetts
Lowing and lifting at the same time is kind of hilarious when you think about it. But yeah I'm not looking to spend a lot of money. I'm kind of amazing how difficult it is for me to just stiffen up my ride. Especially with how boat-like this thing handles, you'd think this would have been a common upgrade for these trucks. Are there any full suspension lifts for this truck that come with new springs? Maybe I could buy just the springs and not the rest? Seems crazy, I dunno.
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
Probably the heaviest spring you could find would be for a V8 EXT for the front and even then, I doubt the difference is much. But I do find my 9-7x V8 fronts and Z71 rears are pretty stiff with great handling. It does have a rougher ride than my EXT I6 with Bilsteins, being a little bouncy in the back.
 

Paul Bell

Member
Aug 16, 2014
460
l008com, you don't tell us what year your truck is or if it's a six or eight but it appears you have a short wheelbase.

I would say "stiffness" of ride is more a function of the shock absorbers than the springs.

The GM catalog lists (I randomly chose 2006) shows different springs for the LWB (25815604 for the rear, 15125886 for the front). The same springs are shown for I6 or V8 applications.

Springs for these trucks are interchangeable for both wheelbases and through all years.
http://www.gmpartsdirect.com/chevro...t/rear-suspension-scat/?part_name=coil-spring
Rancho offers rear shocks and Belltech offers front and rear shocks. If they're any "stiffer" than the Bilstiens, I can't say. FWIW, I run Bilstiens front & rear and I'm happy with the stiffness and ride.
 

l008com

Original poster
Member
Feb 19, 2016
886
Massachusetts
Mine's a 2008 5.3L. Mine has a ride like an 90's lincoln towncar. Great if you're into that sort of thing. I'd probably be a lot happier with a trailblazer SS type ride.

Do springs "soften" with age? This truck does have 114K on it with what looks like original springs. Maybe they're just due for replacement?
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
Z71 rears? Tell me about this please? Also you think the EXT front springs would be stiffer than SS springs?

My 9-7x came with the Z71 springs (from a Tahoe AFAIK) after the previous owner replaced the original airbags with them. They are usually used to lift these trucks, which was the original intention of the previous owner, along with a lift kit. I removed the front and rear lifts, still rides a bit high but handling is perfect. I assume my fronts are stock. Shocks seem stock as well. These could be the determining factor.

Maybe your best bet would be to research over at TBSSOwners for suspension mods. Maybe somebody selling their stock setup could be found?
 

Paul Bell

Member
Aug 16, 2014
460
Springs can sag over time if they're overloaded for a long period of time.

The GM catalog shows the same front & rear shocks for the SS & the non-SS V-8 truck. Not sure if they're different for the I6, but I doubt it.
 

Paul Bell

Member
Aug 16, 2014
460
Yes. Coil springs differed between SWB and LWB but it looks like the shocks were the same throughout.

Springs determine ride height and load capacity.

Shocks determine ride quality, soft or stiff.
 

l008com

Original poster
Member
Feb 19, 2016
886
Massachusetts
Does anyone know how to match up those three letter codes for rear springs, with actual part numbers? The only list of rear springs I've been able to find, has three letter codes instead of the full numeric orderable part numbers. I don't think they are RPO codes either.
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
Are those codes for GMT360/370?
 

l008com

Original poster
Member
Feb 19, 2016
886
Massachusetts
Hey guys. From another post on another thread, I was able to acquire a list of rear springs:

15948005
15948006
15948007
15948008
15948009
15948010
15948011

The 010 shock is the one my truck came with. I assume that means 011 is the softest spring and 005 is the firmest, but I haven't been able to get any specs on the springs.

I'm going to try to move ahead with this soon, so I figured I'd ping this post one more time, just in case anyone has more info on rear springs.
 
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NJTB

Member
Aug 27, 2012
612
Flemington, NJ
Try contacting a spring manufacturer. You may be able to give them the dimensions of the springs you have and go from there.
Be careful, a little difference could mean a lot of change.
 

Sparky

Member
Dec 4, 2011
12,927
I doubt GM directly makes the springs. They often times contract with various suppliers for parts (like they've used Denso for O2 sensors for example). But finding who it is can be rather difficult.
 

l008com

Original poster
Member
Feb 19, 2016
886
Massachusetts
I was looking at my old springs, and there was a tag on them that had the '010 part number, and the three letter code YUZ !! Which was the impossible-to-look-up three letter code from the previous master list. It's a little late but at least now I know I had what may be the softest rear springs available. Doesn't really matter at this point, my Moog ext springs feel great. It just made me laugh when I saw that YUZ on the tag. Nobody had been able to find out ANYTHING from those codes on my spring list.
 
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BrianF

Member
Jul 24, 2013
1,192
West central Sask.
If finding new springs doesnt work try some air bags perhaps. I run a set of coil rites in my ram. The slip inside the coils, need min 5psi to stay afloat. They run a max of 35psi. At 5psi you dont notice them and at 35 the ass end is up a few inches and it rides very firm.
 

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