Rear end sag

[JoshHefnerX]

Ok, when I go on road trips and I load up the car, I'll end up w/ roughly 100lbs in the car between cooler bags ect. It's enough weight that I get high-beamed because it's sagging the rear end and bothering people. I also get this on grocery trips to Costco. So, I'd like to put some audio in the trunk, easily 100+lbs (sub alone is 45lbs), but don't want the rear end sagging. I'd like to stay at stock height. I'm really not interested in coil-overs as they are expensive. Didn't know what you guys had for suggestions - maybe some stiffer springs (from who) or if there were even any load-leveling suspension avail - the aussies got wagons and hitches on the cars and a lot of wagons bet load leveling options because of the weight they carry around.

Any ideas?

Josh

[SpeedRacerX]

When I replaced my stock GT struts & shocks recently with GXP bits, I also replaced the rear stock springs with the Pedders OE height heavier duty spring. Even though it says "OE height" it dropped the back of mine a barely discernable .375" but it did firm up the rear nicely. So, for me, the combo of new shocks to replace the blown ones and the slightly stiffer spring was a great improvement over what I had. No, it does not ride rough - just gets rid of some of the rear end slop and droopiness as the suspension ages.

PM me and I'll tell you where to buy them.

[travis gore]

just upgrade the rear shocks

[SpeedRacerX]

just upgrade the rear shocks

To what?

[SpeedRacerX]

OP: how many miles are on your rear shocks?

[JoshHefnerX]

Forgot to mention a couple of things. I also have a full-size spare in the trunk, which doesn't help to keep the rear from sagging. I have 33k miles on the car. You said the Pedders OE height HD spring still dropped the car a bit? How much diff is it when you start loading stuff in the trunk, and how long have you had those springs and have they settled at all over time?

[switchbladesilver09]

I'm interested in this also.

[-Ray-]

I have a Pedders Street II suspension. With the trunk packed the rear of my G8 didn't sag. The GM rear shocks are junk.

[SpeedRacerX]

Forgot to mention a couple of things. I also have a full-size spare in the trunk, which doesn't help to keep the rear from sagging. I have 33k miles on the car. You said the Pedders OE height HD spring still dropped the car a bit? How much diff is it when you start loading stuff in the trunk, and how long have you had those springs and have they settled at all over time?

It moves MUCH less under load than the stock susp did. Had them on for about 9,000 miles and I still haven't noticed them settle any more.

I agree with Ray that the stock shocks are junk.

Problem is our options and cost.

There are really no good options at or around oe cost. I decided that since my gt shocks were bad at 70,000 miles, in my budget range, the GXP setup from Greg at Pace plus a little bit more for the Pedders oe height springs from Jess, superchargerconnection, accomplished what I needed at a reasonable cost.

Another option, if your shocks aren't blown, are the pedders stiffer rear springs that raise the rear a little and are made for towing etc.

Staying away from coilovers as you stated, your next step up are the pedders gsr's which Ray is referring to within his kit. You can get just the struts and shocks and not the whole kit. Pedders gsr's usually cost 2x the oe but are a great buy when/if pedders has their 50% sale but there are no guarantees of the sale.

I hope that helps.

Sent from my SAMSUNG-SGH-I997 using Tapatalk 2

[-Ray-]

^Good post.

[JoshHefnerX]

Thanks for the opinions. Last time I was under the car the shocks werent leaking yet... So I think I'm going to go w/ the 7955 springs on the stock shocks for now. My front end strut top bushings are getting near done so I'm going to save my pennies and do the gxp shocks/struts and replace the bearings/bushings down the road a bit. I"ll have to see how those springs work out w/ the gxp shocks but that's down the road a bit still.

[SpeedRacerX]

Thanks for the opinions. Last time I was under the car the shocks werent leaking yet... So I think I'm going to go w/ the 7955 springs on the stock shocks for now. My front end strut top bushings are getting near done so I'm going to save my pennies and do the gxp shocks/struts and replace the bearings/bushings down the road a bit. I"ll have to see how those springs work out w/ the gxp shocks but that's down the road a bit still.

You know that's the OE Height HD Spring for Drag/Towing that raises the rear slightly, right? Just want you to be sure.

[EcoBrick Bob]

I have not upgraded my shocks or springs. On my 08' last weekend we had 4 people (700 lbs), a full sized spare and at least 100 lbs of luggage. Car only has 22K. Even though my fenders are rolled, the 285 Bridgestones (stock height) "Zinged" several times on hard bumps. Thinking I will be needing new springs/shocks soon.

[JoshHefnerX]

You know that's the OE Height HD Spring for Drag/Towing that raises the rear slightly, right? Just want you to be sure. yep, it's supposed raise it about 1/4 in. but I figure w/ about 200lbs in the trunk that wasn't there from the factory it should end up right around stock. was hoping if it raised it any more than that - that replacing the bushing/bearing and going to gxp it would flatten out.

The only thing I haven't been able to find is what kind of spring rate those are compared to factory.

[SpeedRacerX]

yep, it's supposed raise it about 1/4 in. but I figure w/ about 200lbs in the trunk that wasn't there from the factory it should end up right around stock. was hoping if it raised it any more than that - that replacing the bushing/bearing and going to gxp it would flatten out.

The only thing I haven't been able to find is what kind of spring rate those are compared to factory.

I believe I read that Pedders states their HD springs are 30% stiffer than the stock G8 spring. I know that's not telling you much.

[skinsfangreg]

Thanks for the opinions. Last time I was under the car the shocks werent leaking yet... So I think I'm going to go w/ the 7955 springs on the stock shocks for now. My front end strut top bushings are getting near done so I'm going to save my pennies and do the gxp shocks/struts and replace the bearings/bushings down the road a bit. I"ll have to see how those springs work out w/ the gxp shocks but that's down the road a bit still.

The shocks can be blown without showing visible signs or leaking. I wouldn't put new springs on the junk stock shocks with 33k on them. You'll likely regret it. The GXP rear shocks are pretty inexpensive. If budget doesn't allow F&R to be done together, buy the rear GXP shocks and new springs now and do the front when budget allows. No point in taking it apart twice IMO.

[TonyKarter]

It is amazing how well it sits with only an investment of $394 in Wal-Mart groceries in the trunk. Infinitely tunable too.

[JoshHefnerX]

lol you ought to see the 'slammed' look w/ a group of 200+lb'ers like myself in it....

[Napalm]

So how many of you have looked at the actual load limits of the car? could it be you are exceeding them? I had 4 people and luggage in my car this weekend and I've got all stock parts and 99+K on the clock and I know my struts are blown.

No sag and no scrub - but I'm also on stock 19's.

Lightest person in the car was up front and weighed 180 something. Everyone else was over 240.


I will say that if you have excessive scrubbing yes you might need struts simply to keep they springs from bottoming out. I wouldn't automatically put GXP struts on your car unless you want the livelier feel and ride.

but the springs - it could be that you've damaged them somehow. I know GTO's have a stock spring issue - but as far as I know the G8's do not. provided you don't over load the car beyond what is on the door placard (and no I don't have that memorized). The first post is a little vague on the overall loading but it almost sounds like you are carrying some extra and if you are going beyond the placard - get the stiffer springs - struts won't really help that issue as they will wear faster being overloaded.

[JoshHefnerX]

I'm not scraping, but am sagging to the point that drivers coming at me highbeam me when I have a load in the trunk. So, I'm trying to be proactive at it.

[Napalm]

That's why I think there might be something else going on.

blown struts don't cause sag. weak springs do. and supposedly the springs on the g8 are appropriate for the load. On the GTO they were not since they used older model springs on a V8 equiped body car (or so the story goes)


I don't see lots of posts about spring sag on the G8 so I'm wondering whatelse might be going on with your car. have you made any suspension mods or added weight to the car recently?

[TLS]

I also have the full size rear spare and jack kit. It does add some considerable weight.

For as easy as it is to adjust...I'd turn down your headlights a tick. Our low beams are VERY bright when cast above license plate height.

[-Ray-]

That's why I think there might be something else going on.

blown struts don't cause sag. weak springs do. and supposedly the springs on the g8 are appropriate for the load. On the GTO they were not since they used older model springs on a V8 equiped body car (or so the story goes)


I don't see lots of posts about spring sag on the G8 so I'm wondering whatelse might be going on with your car. have you made any suspension mods or added weight to the car recently?

This is true, but bad shocks will put more strain on the rear shocks.

[SpeedRacerX]

This is true, but bad shocks will put more strain on the rear shocks.

I think you meant rear springs, Ray.

Sent from my SAMSUNG-SGH-I997 using Tapatalk 2

[-Ray-]

Lol. Thanks Randy. I certainly did.

[skinsfangreg]

To clarify on my post: as has been mentioned here, struts and shocks don't cause sag, springs do. I was suggesting that if your going to go through the trouble and/or expense to replace the springs, you also change the struts & shocks. If your doing the front, you'll also need to replace the bearings (most fall apart when disassembling) and will want to replace the strut bushings (known issue on the G8). After adding those parts to the cost of the springs your up near $500. For another +/-$350, you may as well do the struts and shocks while you have it apart. Not that yours are but, I have seen bad struts/shocks on a G8 with 25k miles.

[JoshHefnerX]

I agree, and was budgeting in a complete replacement... Just didnt want to see the $$ I'm a cheapass when I can be.