Suspension : Stock spring replacement for softer ride

[truckguy82]

3 hours ago, dcarl said:

Maybe this help the original poster: I had the Bilstein 5100's at the stock setting with a Zone 2" Level Kit for 3 1/2 years.  When I decided to make a change, I went with the Eibach Pro Truck Lift which provides the Springs and Shock.  (You use the hardware from the original strut).  The ride was much stiffer than I expected at first.  I called Eibach to inquire about the Spring Rate and was told they 820# (10% higher than the stock spring which puts it around 740#.  I ordered and installed a set of Halo Lifts Boss Coilovers and the spring rate on them is 700#.  The Eibach kit did soften up a little after 1000 miles or so but I had already ordered the

Boss Coilovers.  You can see how beefy the Eibach Spring is on the left vs. the Eibach Spring on the Boss Coilover.

 

Even with the Coilovers installed with (2) spacers giving it a 3" lift rides better than the Bilstein or Eibach strut.  I am going to remove the spacers and drop it back down to a 2" lift because at 3" it puts too much angle on the other components even with new UCAs.  Theoretically it should also ride smoother at 2" instead of 3".

 

.  

The rear springs have a lot to do with the ride, I think more to do with it then the front.

 

I had bilsteins just installed on the rear for a couple months, made a big difference in the overall ride.

 

I mean if you put 1k lbs in the bed centered over the rear axle, the ride gets a whole lot better and it puts zero extra weight on the front axle. Which is pretty much proof that the rear axle is a huge part of the ride quality. Upgrading the shock can only take you so far.

 

I mean what’s the weight distribution on our trucks, like 60/40 front/rear? Lets just say it is.

 

That means when GM had to choose the springs for a 2k lb payload, that means they had to have springs that suspend 2200lbs unloaded and 4200lbs loaded. Short of variable spring system such as airbags, its pretty much impossible to design a spring that can perform in that wide of weight margin.

 

So basically, ultimate ride quality and performance = significantly softer rear springs + airbags + 4 shocks+ Front coilovers

[Grinnen]

Currently from all pickups I have driven the Dodge Ram Outdoorsman was like driving a sofa sitting on a cloud over calm water. No other pickup I have driven has a ride of that quality. Too bad their suspensions die quickly (among a few other issues).

 

I won't quote everyone but dcarl pretty well nailed what I was trying to get across.

More coils that are a smaller diameter in thickness, and at the same height as stock, would offer a much more forgiving ride I think. Same with the rear, 3 leaves VS 5 thinner leaves would provide a more supple ride. The spring rates would have to match though.

The heavy duty coils and rear leaves are meant for work trucks on most of the 1500 series. I have a feeling that these are what people are feeling that are giving the rough ride versus the Rancho stock shocks (which aren't perfect by any means but I don't think are helped by the coils/leaves). When people put in a lift this all changes and gives a better ride (so I have also experienced)

Now I need to research what coil/leaf combo would give that softer ride I'm seeking. 

Edited May 30, 2019 by Grinnen

[lucas287]

Let's resurrect this thread! I too think the front end is entirely too stiff. Combine that with 275/55R20's and it's a bit much. Also, everyone is entitled to their own opinion of how THEIR OWN truck should ride. I don't think there is any place for comments like "wow, why do you drive a truck?" or "you think that's rough! Try owning a 3/4 ton", or worse yet, "buy a Honda Ridgeline". 

 

Anyways, I did some sleuthing on GM Parts and found that there are about a dozen different spring options for these trucks. The same for Tahoes, Suburbans, and Escalades. But it's darn near impossible to find the actual spring rate. I think we can all agree that a LT trimmed Tahoe or Suburban rides fantastic all things equal compared to a Silverado/Sierra. The coils that come on the smooth ride package is what I'd consider experimenting with. 

 

I think I'm gonna hit up a Tahoe forum and see if anyone has some coils laying around after a coilover swap or something and see it they'd part with them on the cheap. 

[lucas287]

I called Bilstein and asked about the 6112 kit and they said the springs are 750# - too stiff for me! I started researching other options and found this. 

 

https://atomicfabandperformance.com/product/07-18-gmt900-front-coilover-package/

 

This setup seems like the best option for someone wanting complete control over the setup! Pick your ride height and he will select the coilover and spring length needed then you select your desired spring rate based on use. He doesn't recommend going any lower than 650# springs. Plus you get to fine tune compression damping and rebound damping! 

 

But maybe all that is a moot point if the rear is still stiff as hell. 

 

I do have a Deaver Mini pack that I'm thinking about experimenting with. What if I removed the middle leaf spring? The one in between the overload and top main spring. And in it's place put the deaver mini pack? Which is basically three springs. Should overall reduce spring rate and make it more progressive. 

 

[lucas287]

Was perusing RockAuto and took a look at the KYB pre-assembled struts. Looks like they are Gas-A-justs which is a monotube shock. New spring, upper mount, whole nine yards. I started to cross reference their part numbers to see if it changes based on RWD and 4WD and it does. Then I looked at Suburban and Tahoe, RWD and 4WD. 

 

KYB specs the same part # for a RWD Silverado as a 4WD Suburban. Hmm... makes me think that a Suburban 4wd has similar spring rate to a RWD Silverado. 

 

The RWD Suburban has a different part number altogether. Those might be the winner! 

 

And BTW they all use the exact same actual shock. The difference in part numbers might be due to upper mounts but I doubt it. 

[lucas287]

On 5/30/2019 at 11:07 AM, Grinnen said:

Currently from all pickups I have driven the Dodge Ram Outdoorsman was like driving a sofa sitting on a cloud over calm water. No other pickup I have driven has a ride of that quality. Too bad their suspensions die quickly (among a few other issues).

 

I won't quote everyone but dcarl pretty well nailed what I was trying to get across.

More coils that are a smaller diameter in thickness, and at the same height as stock, would offer a much more forgiving ride I think. Same with the rear, 3 leaves VS 5 thinner leaves would provide a more supple ride. The spring rates would have to match though.

The heavy duty coils and rear leaves are meant for work trucks on most of the 1500 series. I have a feeling that these are what people are feeling that are giving the rough ride versus the Rancho stock shocks (which aren't perfect by any means but I don't think are helped by the coils/leaves). When people put in a lift this all changes and gives a better ride (so I have also experienced)

Now I need to research what coil/leaf combo would give that softer ride I'm seeking. 

Agreed on the RAM. Almost bought a new stripped down 2wd RAM because of how nice it rode. Too many other things that bothered me though. 

 

Your thoughts on the coil spring design are directionally accurate. Fewer, smaller diameter springs is actually stiffer. More, larger diameter is softer. Generally speaking of course. 

[lucas287]

More on the KYB loaded struts. This first pic is KYB SR4544 for a 2wd Tahoe. Notice the spring design having more coils and larger diameter?

Edited May 29, 2020 by lucas287

[lucas287]

KYB SR4546 for a 4WD Suburban or a 2WD Silverado with the V6,...

 

[lucas287]

And the KYB SR4547 for a 4WD Silverado 1500. 

 

[lucas287]

I used this calculator to conceptualize the difference in spring rate between KYB SR4544 and KYB SR4547. The actual measurements don't matter as much as being able to understand the basics of spring rate. 

 

https://www.blueovaltrucks.com/tech/coilspringrate.htm

 

Let's assume that they use the same diameter wire to produce these three different coils and also due to packaging constraints there mean diameter is the same too. 

 

I used values of .6" wire diameter, 4" mean diameter, and then the only variable is changing the amount of active coils. KYB SR4544 has 6 active coils vs 4 active coils for KYB SR4547. The results:

 

KYB SR4544 = 475 #

KYB SR4547 = 711 #

 

I'm NOT saying these are the rates. I'm simply illustrating that all else equal the more active coils the lower the spring rate which makes me think KYB SR4544 does indeed have a lower spring rate. The shock body itself is identical, which means valving is the same. The upper strut mount is the exact same too. 

 

So, what does one think the front end of a 2WD Tahoe weigh? According to autoblog.com, a RWD 2016 Tahoe LT package weighs = 5,355 lbs with a weight distribution of 52/48. 2,782 lbs on the front half of the vehicle. 

 

My truck, a 2016 Silverado 1500 4x4 High Country CCSB (mine has a 8L90 so probably a bit heavier) weights = 5,370 lbs. Weight distribution is 58/42. 3,115 lbs on the front half of the vehicle. 

 

2016 Suburban 2WD curb weight = 5664 with a 51/49 split. So, 2900 lbs on the front half. 

 

 

[lucas287]

Now, I'm thinking KYB SR4545 is the perfect match. It's for a 2WD Suburban which weighs a bit less than a Silverado 4WD on the front end. Once again guys the upper mount is identical, the shock itself is identical, just the springs are different. 

 

This is a $300 bolt right in solution. Potential solution that is. I do suspect the front end will drop a bit though....

[lucas287]

@Grinnen

[lucas287]

@truckguy82

[Snowcamo]

I think your on to something. Good job on resurrecting this thread.

Sent from my LM-G820 using Tapatalk

[lucas287]

Extrapolating more of this data...

 

We know a Silverado 4x4 has somewhere in the neighborhood of 750 # springs. Why? Halo Boss uses 700 # springs and reviews note that it's softer. Bilstein 6112 are 750#. 

 

If the front of 4x4 Silverado weighs 3115 pounds and it uses 750# springs - what rate are the Tahoe springs?

 

750/3115 = .241

 

.241 * 2800 = 675

 

675 pound springs is my best guess. But - if you use these springs on a heaver vehicle the front will sag more, right? yes! more math,...

 

Let's use 3,115 pounds as a constant and 750 # springs as a constant. 3,115/2 = 1557, call it 1560 lbs per side. (I know this is very crude but hang with me) 1560/750 = 2.08". This means when you apply 1560 pounds of weight to 750# spring it will compress 2.08". Let's do the math on a 675 # spring. 1560/675 = 2.33". This means the front will drop exactly .25". In theory, of course. 

Edited May 29, 2020 by lucas287