Sierra Denali Bouncy Ride After Shackle & Shock Relocator Installation

[nv6425]

Guys,

 

I installed lowering shackles and the corresponding shock relocator kit on my 2018 Denali and when I'm solo in the truck, it's a bit bouncy but when I have anyone else in the truck, especially in the back seat, it's so bouncy you want to puke.  I also installed a BAKFlip MX4 so I'm sure that added some weight to the rear.  Honestly, I love the look of the truck with the lowering shackles but the ride is absolutely horrible when I have anyone in the truck with me.  Any thoughts on what could be causing this?

 

Thanks in advance!

[HeySkippyDog]

I'm going to give you this one free of charge.

It's because you put lowering shackles on and relocated your shocks.

Your springs are going to respond differently, and the damping of the shocks is not what it used to be anymore because it was designed to dampen the original configuration. Your shocks may be held more partially compressed than they normally would be, and that's gonna make things bounce a lot more too.

Your lowered truck will not be riding nearly as smooth as it was before.

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[1SLOW1500]

Rake. And shocks. You can mess with cheap ways to fix it or just do it right and add a air bag. I can't possible speak high enough of the air bag. 

If the rear lower kit is 2" or less there are nice large bags that bolt right in and sit inside the Frame. The smaller linear bag that is over leaf is set up for 6,7,8,9 drop. 

Trust me look into it. 

[goeb34]

Post pics

[jackgraves]

You also need to check your Pinion Angle. When I used the lowering Shackles and took out my 1 inch blocks. I had to shim my rear end up 2 degrees. Now my transmission u-joint is negative 1 degree and my pinion is positive 1 degree. They now cancel each other out and I have no vibration issues.

[HeySkippyDog]

I don't think vibration is the problem. It sounds like the truck rides like a hoopty.

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[Grumpy Bear]

Been awhile since I did the measurements but the rear shock has about 9" of travel. In any other world but trucks the proper shock location would have the shock sitting 4-1/2" compressed, mid range. An empty half ton will have the stock setup sitting 2-1/2 to 3" further towards the top of the stroke so that when at full rated load it is indeed at mid range. The shock doesn't really care where in the range it is as it concerns dampening but empty it can top out pretty easy. (Washboard dance)

 

Now that you have a point of reference and not stating how much shackle or stock relocation was involved a good place to start would to be measuring the exposed shaft from body to eyelet/shaft weld and knowing fully extended is roughly 9 inches see where she is sitting. Then place a zip tie around the shaft snuggly against the body and see how much of the travel is being used currently. Drive it around a week or so under as many 'normal' conditions as possible. You should be able to calculate both the compression and the rebound distances.

 

Once you know the compression distance measure the distance between the bumper and axle. My bet would be that your hitting the bumper or one shock limit and while they, bumpers, are progressive in nature they have zero dampening value. Unloads the valve pack when that happens.   

 

On my truck I almost never carry anything over a few hundred pounds so when I set up my King set up I targeted mid shaft at no load. If it's your work truck and you haul heavy then as 1SLOW1500 noted bags are your friend. 

 

When you do a drop like this the space between the bumper and the axle is reduced a bit more than one to one with your drop distance no matter what your method. You would rather hit the bumper however than bottom the shock. A good reason to know exactly where you are in the stroke especially if you start cutting bumper length or reducing bumper mount thickness. You may find, considering your actually usage of the truck that the shock relocation wasn't needed or even working in your favor. I used Deaver springs de-arched 2" and removed the factory 1-1/4" spacer, use King OEM factory length shocks and am sitting dead center of the travel with over 3" of drop. I elected to keep the stock length bumpers and mounts and yes I sacrificed compression distance. About an inch of unusable travel but I can't recall in some 50,000 miles ever hitting the stop. Each case is different because each truck is used differently.

 

Note of caution. If you ever decide to trim the bumper length you DRASTICLY reduce it's progressive nature. You might not notice it at a half inch less but more is like hitting the frame.  

 

 

 

 

[Pearl2017]

Do you have magnaride shocks? it is my understanding that the damping is variable and that changing the height can throw them way off. Last guy with a similar question it was riding like stone.

[HeySkippyDog]

Do you have magnaride shocks? it is my understanding that the damping is variable and that changing the height can throw them way off. Last guy with a similar question it was riding like stone.

It's a Denali, it definitely does.

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[1SLOW1500]

I would measure the distance between the bump stop and axle. If you feel that it hits just grap the foam stop and pull it out. Drive and see how it is. They sell different stops or people cut the stock one.
Before you started you should have had the truck on a level ground and measured from ground to center of fender lip top center. So you know exactly what you drop is. Many people my self included forget. If it is a magna ride keep the lowering mount for the shock, check the stop, and I would add bag. Even on a stock truck with no heavy load it reduces the bounce. Watch some YouTube videos on it.
It is very important to check pinion angle. Axle wrap loads the springs in a very uneven way. A shim at the axle or trans can resolve all of that.

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[wforrest08]

Read though this thread you have to “adjust” the length of leveling rods on the rear for the magnetic shocks. This is a must anytime you raise or lower the ass end of the Denalis. The rod has to be centered for the mag system to work right now the system thinks the truck is sagging in the rear and the shocks are trying to compensate for the weight that isn’t there. There’s several other threads on this site about this you can “mod” the rods or order a kit from a company like McGaughys

 

 

This thread explains it better than I can and there’s pics of a adjustable rod

 

 

Edited February 15, 2019 by wforrest08

[Grumpy Bear]

Magnetic shock system? Forget I spoke. Sorry missed that. Ops......

[nv6425]

On 2/15/2019 at 10:19 AM, wforrest08 said:

Read though this thread you have to “adjust” the length of leveling rods on the rear for the magnetic shocks. This is a must anytime you raise or lower the ass end of the Denalis. The rod has to be centered for the mag system to work right now the system thinks the truck is sagging in the rear and the shocks are trying to compensate for the weight that isn’t there. There’s several other threads on this site about this you can “mod” the rods or order a kit from a company like McGaughys

 

 

Thanks for all of the thoughtful replies.

 

Are the leveling rods required if I've used the shock extenders?

 

This is the kit I used: https://www.suspensionsuperstore.com/2015-2018-gmc-sierra-denali-1500-2wd-4wd-2-rear-leveling-kit-prs-152l/

 

This is specifically for a Denali with Magnetic Ride.

 

[nv6425]

On 2/14/2019 at 7:51 PM, HeySkippyDog said:

I'm going to give you this one free of charge.

It's because you put lowering shackles on and relocated your shocks.

Your springs are going to respond differently, and the damping of the shocks is not what it used to be anymore because it was designed to dampen the original configuration. Your shocks may be held more partially compressed than they normally would be, and that's gonna make things bounce a lot more too.

Your lowered truck will not be riding nearly as smooth as it was before.

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Thanks for the help - I was under the impression that the shocks would act the same because of the relocators?  Should I be considering different springs?

[wforrest08]

54 minutes ago, nv6425 said:

Thanks for all of the thoughtful replies.

 

Are the leveling rods required if I've used the shock extenders?

 

This is the kit I used: https://www.suspensionsuperstore.com/2015-2018-gmc-sierra-denali-1500-2wd-4wd-2-rear-leveling-kit-prs-152l/

 

This is specifically for a Denali with Magnetic Ride.

 

Did you do this? If not that’s where I would start.

Notes-

• You will need to take vehicle to Dealer and have a "Trim Level Relearn" to correct rear magnaride settings
• Works With Magnaride suspension