PPV Front and Rear Coil Spring Replacement

[iamdub]

So again... Does the sway bars make a difference in ride comfort? If so, what have others swapped theirs with to make a difference?

In short, yes.

The only way I can see sway bars making a difference in "ride comfort", assuming that means normal, straight-line driving, is when hitting any off-angle bumps/dips that would cause one side of the suspension to be at a different height than the other. If you were to hit something squarely that spanned the roadway, such as a blowup or speed bump, and both sides of the suspension cycled the same amount and at the same time, then the sway bar would have no affect on the firmness.

But, there are transfehardly any instances where you'd encounter such irregularities on the road. Most are a dip or bump, slight low or high spots, etc. that only one side of the vehicle rolls over or at least one side is affected more than the other. Anything uneven left-to-right is going to affect the other side. That's what sway bars do- they connect the two sides. A stiffer sway bar will make this uneven cycling more noticeable since it will transfer rather than reduce the absorption of the cycling. But, in my opinion, it's not enough to outweigh the benefit of the stiffer sway bar(s) when cornering.

As far as nosediving, I don't see how stiffer sway bars could affect this, either. If you were driving straight and slammed on the brakes, both sides of the suspension will cycle the same direction, at the same time and the same amount. Both ends of the sway bar would swing upward at the same time and the same amount. If you had both end links of your sway bar disconnected, you could swing the bar up or down easily with one hand with very little resistance. During a nosedive, the suspension cycles the same way, only it's a control arm on each end pushing both ends of the sway bar up instead of a human hand. The bar still has very little resistance. Now, any off-angle nosedive, such as when swerving and slamming on the brakes to avoid a collision, a stiffer sway bar would absolutely make a difference.

I believe the engineers specified a sway bar that struck a balance between resistance to body roll and side-to-side compliance. This decision also had to suit both the purpose of the vehicle and the average operator of the vehicle. There are always people that, based on their personal preferences due to driving style or environments (mostly smooth or mostly rough roads,etc.), would want something a little firmer or softer.

 

[balln2k11]

In short, yes.

The only way I can see sway bars making a difference in "ride comfort", assuming that means normal, straight-line driving, is when hitting any off-angle bumps/dips that would cause one side of the suspension to be at a different height than the other. If you were to hit something squarely that spanned the roadway, such as a blowup or speed bump, and both sides of the suspension cycled the same amount and at the same time, then the sway bar would have no affect on the firmness.

But, there are transfehardly any instances where you'd encounter such irregularities on the road. Most are a dip or bump, slight low or high spots, etc. that only one side of the vehicle rolls over or at least one side is affected more than the other. Anything uneven left-to-right is going to affect the other side. That's what sway bars do- they connect the two sides. A stiffer sway bar will make this uneven cycling more noticeable since it will transfer rather than reduce the absorption of the cycling. But, in my opinion, it's not enough to outweigh the benefit of the stiffer sway bar(s) when cornering.

As far as nosediving, I don't see how stiffer sway bars could affect this, either. If you were driving straight and slammed on the brakes, both sides of the suspension will cycle the same direction, at the same time and the same amount. Both ends of the sway bar would swing upward at the same time and the same amount. If you had both end links of your sway bar disconnected, you could swing the bar up or down easily with one hand with very little resistance. During a nosedive, the suspension cycles the same way, only it's a control arm on each end pushing both ends of the sway bar up instead of a human hand. The bar still has very little resistance. Now, any off-angle nosedive, such as when swerving and slamming on the brakes to avoid a collision, a stiffer sway bar would absolutely make a difference.

I believe the engineers specified a sway bar that struck a balance between resistance to body roll and side-to-side compliance. This decision also had to suit both the purpose of the vehicle and the average operator of the vehicle. There are always people that, based on their personal preferences due to driving style or environments (mostly smooth or mostly rough roads,etc.), would want something a little firmer or softer.

Thank you so much for the great detailed example of the sway bar. I’m going to disconnect the front, then rear and see what impact it makes just driving around (not taking corners) I also like the other feedback about using a 1/2 pickup sway bar from a Sierra/Silverado and see the difference. This forum rocks! Just need to find the time with my crazy weekend(s).

 

[iamdub]

Thank you so much for the great detailed example of the sway bar. I’m going to disconnect the front, then rear and see what impact it makes just driving around (not taking corners) I also like the other feedback about using a 1/2 pickup sway bar from a Sierra/Silverado and see the difference. This forum rocks! Just need to find the time with my crazy weekend(s).

I'd advise against driving a 3-ton, top-heavy SUV with no sway bars over about 30 MPH! If you must, test it with nobody around, only go straight, be mindful of over-steering and be ready to slam the brakes if the oscillations grow too much.

I unplugged my electronic shocks one day as a test. Cruising about 45 MPH, I noted that the straight-on ride was much softer, actually TOO soft. I quickly jigged the steering wheel and the amount of body roll caught me off guard. I am by no means a novice driver and have throttle-steered almost everything I've ever driven that was rear wheel drive. One of these vehicles with what would essentially be completely blown shocks and only sway bars to keep it stable could very easily get out of control if you had to make a quick lane change or even if you caught a strong side wind. I'll also add that my sway bars have firmer polyurethane bushings.

 

[Ilikemtb999]

I’ve never seen a Chevy pickup with a rear sway bar. In fact I added a suburban one to my old 2wd truck. Maybe that one is bigger than a Tahoe one since there’s more weight?

 

[GCATX]

I know this is an old thread, but did anyone confirm that the front and rear sway bars played a role in the stiffness of the ride comfort? I know the PPV sway bars are heavy duty vs. the civilian models and designed for better cornering.

I just ordered Eibach 2” drop rear springs to see if it helps with my harsh ride as others have mentioned with the Belltech brand. I already changed all shocks/struts with Belltech Street Performance and made very little difference.

Oh, Eibach is closing out production of their springs for 07-2014 Tahoe/yukons and fire selling them. They already sold out on the fronts but still have the rears. Check out their website.

I am curious if the Eibach springs helped out. I also ordered a set, $58 shipped, kind of a no brainer. Hopefully they will be here in a week or two, they said they pretty much shut down around Xmas. I also have some new regular tahoe rear shocks to go on at the same time.

 

[Nima]

Does anyone know the rating for the springs on the 2015 ppv?
I talked to one of the engineers at Gm and he told me that in order to change the shocks to civilian I need to change many other components. I replaced them with a new original ppv and it improved 5% maybe. I am already about 1800$ in it and very disappointed to see a change. I am gona give it a shot and change the back springs as well but need the rating . If anyone knows please share
Thanks

 

[ID4W]

Has anyone replaced their tight police package springs with something a little softer? I'm not talking about converting to a civilian suspension, just a replacement spring that would give more than the ppv's. There are so many vehicles with struts and rear coils that there has to be one that interchanges and still keeps the rest of the componants in play. Not wanting to lose the stance too much.

I will continue to research this and post any findings.

I was shocked when I looked under the rear of my 2013 ppv and noticed only about 1” max of travel clearance between the rubber bump stop and the axle pad. I literally reached under and pulled, pushed, and twisted the rubber bumper out of the frame and the ride was much better when the suspension could move. The bump stop is only held in place by an interference fit and some small metal tabs bent toward the rubber inserts. No hardware or tools required to remove. I was concerned about bottoming out over large bumps, but I don’t believe it has ever come close with the stiff springs. I specifically wanted the ppv because of the factory lowered suspension, but I’m still bothered that the vehicle doesn‘t sit level, so today I unbolted the sway bar and shocks to remove the springs to measure clearances and shock lengths. I would like to lower the rear, maybe 1” max, and raise the front by 1/2” - 1” with spacers under the strut to lower control arm mount, or at the top of the strut to pedestal 3 bolt mount. This would level out the 1-1/2” ride height problem. I will shorten the rear bump stops.

 

[Jimgeorge]

Just a simple question on the sway bars. Purchased Eibach rear 2” drop springs. Hope to get to them next weekend and take photos of the different in size and what note.

I got 2 inch drop for front and rear from DJM. The front dropped 2 inches but the rear only dropped 1/4 inch so I talked to them and they said I need the 4 inch drop for the rear because it is a PPV. That dropped it about two inches. Also put on a Heilwig front sway bar. The OEM is a hollow tube and 1 inch diameter. The aftermarket is solid rod and about 1.5 inches.

 

[Jimgeorge]

I disagree completely. I upgraded my swaybars to DJM from stock Denali's and the new ones are much heavier. The ride is exactly the same however cornering is nearly completely flat and nosedive under heavy braking is nearly nonexistent. I've upgraded swaydars on many vehicles throughout the years and the result has been the same. Its what they're meant to do. But if you want to disconnect your front swaybar completely by removing the endlinks, that's not the same as comparing a smaller swaybar to a bigger one.

I replaced mine with a Heilwig. It was a solid bar instead of a tube and it had a larger diameter.