Suspension Modification For Z71

gmyeah · February 27, 2011

I have a 2008 Z71 ext cab and love it. Can't say enought about it, but there is a but. I'm pretty good with the towing capability, but is there a way I could increase my payload at all? As I recall, the GVWR is 7000 lbs - 5300 lb truck - 200 lb me = 1500 payload capacity. Rough numbers....I know I'm a bit off on them. I tell ya though...I've tried putting a pallet on the axel that was about 1200 lbs and it really wasn't that pretty. Just really looking for a little more capability without sacrificing my truck's handling when there's no load in it. I know I should just suck it up and get a 3/4 ton, but the gas mileage is a bit steep and was hoping i could modify mine a bit. any ideas? Thanks!!!

I've heard that the 3/4 tons have what they call asymetrical leaf springs??? Not sure if I could add or change that up....not sure what that's completely about.

Stevens03 · February 27, 2011

D-rated tires would have vastly improved your truck handling the load. You could also add a leaf to the spring pack. Both would be a big improvement over the stock setup.

They also make spring helper that bolt on and are progressive. I've used those in the past and they work. Factory ride till you add a load.

cujo8 · February 27, 2011

Hellwig makes progressive helper springs:

http://www.sdtrucksprings.com/index.php?ze...;x=170&y=25

Air-Lift has Air-helper springs that work well:

http://www.sdtrucksprings.com/index.php?ma...roducts_id=6237

Like Stevens11 stated you should get some Load Range D or E LT-tires along with the helper springs. I did all this on my 2006 GMC to help my haul heavy loads in my truck while hauling a fully loaded 16' utility trailer (Firewood). I bought a set Hankook Load range E LT tires and they never squatted with any of the loads I haulled, but they could hold more weight than the truck could, since they were load range E tires. I know these were over kill for my truck, but they didn't carry a load range D tire in my size.

gmyeah · February 27, 2011

So... do the helper springs change the look of the truck as well? Does it raise the back up a bit. I ask only because of GM's rake issue in there 1/2 ton pickups. I've toyed with putting in a Rough Country 1.5" leveling kit in the front......but I can live with the way it looks now (since a took a thin piece of facia of the front). It's amazing what a little change does to the truck. I know this specific post is more about cosmetic, but I just want to make sure I know what I'm getting into. Also, the squatting i was referring to was the truck's suspension...not the tires necessarily, but that is still go info. Ballpark...what do you think it adds in payload capacity?

cujo8 · February 27, 2011

So... do the helper springs change the look of the truck as well? Does it raise the back up a bit. I ask only because of GM's rake issue in there 1/2 ton pickups. I've toyed with putting in a Rough Country 1.5" leveling kit in the front......but I can live with the way it looks now (since a took a thin piece of facia of the front). It's amazing what a little change does to the truck. I know this specific post is more about cosmetic, but I just want to make sure I know what I'm getting into. Also, the squatting i was referring to was the truck's suspension...not the tires necessarily, but that is still go info. Ballpark...what do you think it adds in payload capacity?

The progressive helper springs will not change the ride height of the truck or unloaded drive characteristics. The word progressive means that the spring rate changes with the amount of load you put on your truck, so unloaded it lets the stock springs carry the weight for the most part, but As you load the truck they start they give you higher spring/load carrying capacity. The link I gave you for the Hellwig springs say they add ~ 2000 to 3500lb capacity depending on which springs you buy. Actually they call it load leveling capacity, so these springs keep the truck more level when it loaded, but you need to remember that the load carrying capacity of your truck is dependent on more than just what your springs can carry, it a combination of frame, axle, spring, tire, and wheel capacities. Therefore your load capacity is only as good as the weakest link in that combination. That being said then if the Springs are the limiting factor than by increasing your spring capacity you have increased your load carryimg capacity. The manufactures of these helper springs will always warn you that even though these springs will help keep your truck from squatting down they will not allow to carry more weight than is stated in your owners manual. They have to say that to Cover their A**, but I feel that you do get some added load carrying capacity with these upgrades, but you do have to use some common sense as to how much is reasonable.

I owed a set of Hellwig Helper Springs and although they did do what they were advertised for I didn't like them because they rattled when not carrying a load. I tried adding more preload to them, but they still rattled too much for my liking. I removed the Hellwigs and went with an Air-Lift helper spring system that included an on-board air compresser and gauge setup. This setup worked great and you can add or remove air as needed from the comfort of the cab and they never rattled.

gmyeah · March 6, 2011

ok. So i've read pretty much all the threads on the rough country 2" leveling kit (an looked at the pics) and that's something that is related to this susupension modification I'm considering. I don't really mind the rake that much, but it does look a bit odd on my 08 sierra z71. But I feel if I do add that on to the front, I may just use the 1/4" and 1/2" spacers to get a 1-1/2" total lift in front. After the install, on paper, I'll have a 1/2" - 1" difference between my front and rear. That's better than what I have now stock (and I would be fine with that), but I do tralier and I do espeicially load up the bed (i.e. firewood). When I do this now, the truck squats bigtime, but honestly looks fairly level in the squatted position. If I do the RC 1-1/2" level...I worry when i load it up, my front end will look like I aiming to the moon unless I do something to the rear end of the truck. Interestingly enough I am trying to get a little more payload capacity in the back like i mentioned...so maybe the suggestion of adding a leaf or going with the Hellwig option works. Seems like that would add some height in back as well? not looking to do that. Any suggestions. I saw a lot of differnet setups listed, but none that quite want to do this. Bottom line, aesthetically I do want to remove a little rake, but at the same time I don't want the rear end to squat way low which would ultimately look pretty bad and probably wouldn't be too good for trailering. along with this...a little more payload capacity. Thoughts?

cujo8 · March 6, 2011

ok. So i've read pretty much all the threads on the rough country 2" leveling kit (an looked at the pics) and that's something that is related to this susupension modification I'm considering. I don't really mind the rake that much, but it does look a bit odd on my 08 sierra z71. But I feel if I do add that on to the front, I may just use the 1/4" and 1/2" spacers to get a 1-1/2" total lift in front. After the install, on paper, I'll have a 1/2" - 1" difference between my front and rear. That's better than what I have now stock (and I would be fine with that), but I do tralier and I do espeicially load up the bed (i.e. firewood). When I do this now, the truck squats bigtime, but honestly looks fairly level in the squatted position. If I do the RC 1-1/2" level...I worry when i load it up, my front end will look like I aiming to the moon unless I do something to the rear end of the truck. Interestingly enough I am trying to get a little more payload capacity in the back like i mentioned...so maybe the suggestion of adding a leaf or going with the Hellwig option works. Seems like that would add some height in back as well? not looking to do that. Any suggestions. I saw a lot of differnet setups listed, but none that quite want to do this. Bottom line, aesthetically I do want to remove a little rake, but at the same time I don't want the rear end to squat way low which would ultimately look pretty bad and probably wouldn't be too good for trailering. along with this...a little more payload capacity. Thoughts?

Both the Hellwig and AirLift helper springs will keep your truck from squatting when fully loaded and they do not add any additional height in the year when properly adjusted. The Hellwig springs are a progressive style, so they don't really kick in until you load the truck, this way they don't hurt the ride characteristics when the truck is unloaded. The one thing I didn't like about the Hellwig helper springs is they some times rattled when you go over bumps when the truck is not loaded. That is the reason I went with the Air Lift helper springs with the on-board compressor, since it accomplished the same thing as the Hellwig setup, but without the rattle issue. With the AirLift airsprings you always leave at least 10psi of air in the bags to keep them inflated when the truck is unloaded and you add air to level the truck when loaded. With the on-board compressor setup you can add and remove air from the comfort of your cab and you have a pressure guage to monitor the pressure. The AirLift setup w/o the compressure you have to add/remove air manually through a shrader valve, which you can mount in an convienant location.

If you still want to level your truck you will have to do that with a separate kit for the front of your truck. One option for leveling your truck and improving the ride characteristics at the same time is with Bilstein front strut system. They have adjustable spring purchases to adjust the front ride height up to 2-1/2". If interested in this option there is a thread on this I just read on the subject here on this site. Good luck on your project and let us know what you decide on in the end.