Hellwig Rear Sway Bar On 2020 Sierra Denali

Rook126 · November 22, 2020

Even though I have the trailering package and Adaptive Ride Control, I always wondered why my Sierra swayed much more than my 2018 Tahoe. Even my passengers would comment about the bouncy swaying ride when making turns. I recently looked under the truck to see how thick the sway bars were and realized there was no rear sway bar. The Tahoe, Yukon and Escalade come standard with a rear sway bar. It didn't take long for me to bite the bullet and pay the steep price of $500 for the Hellwig 7780 rear sway bar kit. Ordered from Amazon without Prime but still arrived drop shipped from Atlanta in two days. I had the chance to install it last night.

Like others on this forum have mentioned, the instructions were just about useless and lacked details on different bushings, sleeves and two different end link bolts provided. One was course threaded and the other was fine threaded and slightly longer. The shorter bolt was too short to be used on the end link and over compressed the bushing after starting the lock nut. I basically figured out how to install the kit by a diagram provided and examining posted images from others. I pre-assembled the parts to make sure everything was included. It was a fairly easy job only took a couple hours. I did have two metal brake lines running on the inside of the frame on the driver's side. Be mindful when placing the U bolt over the frame on the driver's side and make certain you have a wide enough gap between the lines and the frame.

Overall, the difference in handling and lack of sway was immediately noticeable even with an empty bed. The truck stays level on while cornering and on curves while the ride is still smooth and comfortable. Even my passengers noticed it and said it "no longer feels like a dune buggy".

To me it was worth the price for the upgrade. Here are some images for those who are curious.

M1ck3y · November 22, 2020

I can understand a sway bar on the front or independent suspension , but a sway bar on a solid axle... But hey, if you got the outcome you were looking for, good on you.

Rook126 · November 22, 2020

17 minutes ago, M1ck3y said:

I can understand a sway bar on the front or independent suspension , but a sway bar on a solid axle... But hey, if you got the outcome you were looking for, good on you.

Thanks. I believe that even with the straight axle the sway bar is preventing the truck body/frame from twisting against angle of the axle. Say for instance when you are making a sharp left turn, your right front corner usually dips and the left rear usually raises. The sway bar prevents the left rear from lifting and does it's best to keep the frame and body parallel with the axle. I'm just glad it works and improved the ride.

pewterliftedz · November 23, 2020

Interesting, even with changing the suspension to sport it wouldn’t control body roll?

Rook126 · November 23, 2020

Correct. After comparing Normal drive mode and Sport mode, I didn’t really notice a big improvement with handling or sway control. I wish sport mode would have dampened the ride more than it actually does. I do notice the power steering becomes stiffer and the shift points seem later in higher rpm. In sport mode the truck still rolled too much for my taste while turning corners at normal speed. This rear sway bar made the biggest difference over driving modes.

Here’s another example I noticed today when driving with my small dog standing on the back seat (on a doggy mat over the seat). In the past he would get flung around when he tried to stand up because the truck leaned to the point where he couldn’t get a grip on the mat to brace his legs during normal turns. When I drove him today, I noticed that he was able anticipate the turns and brace himself. He stood up on the mat during most of the drive and didn’t seem to have a difficult time with his balance. This is likely due to the truck keeping even more level on turns and curves. At this time I believe my decision to install the bar was a good one.

kodiakdenali · November 23, 2020

subbed and added one of those to my cart as well. I didn't know aftermarket sway bars even existed for these trucks.

I noticed the same thing as you from day one with my Denali, the body really sways when making turns. I don't like that one bit. stepping on the steps to get in, major body rock. worse is that just making sharp turns at low speeds (parking lot maneuvers) causes an astonishing amount of lateral sway in the body, I would not expect that with all the sophisticated stuff that's under this truck. my last truck was an 03, and it was miles better than my 2020 in that regard. sure the Denali rides wonderfully, handles bumps extremely well and all, but the body sway...its just ridiculous.

looks like a pretty easy install?

Rook126 · November 24, 2020

Yes, an easy install. I had enough room to work under the truck without having to jack it up. One of the issues I had was deciding the orientation of the end-links, which end was up and which was down. The instruction diagram showed the threaded end at the bottom and another diagram showed it at the top. I ended up putting the threaded end at the top. It comes with four black bushing and four metal sleeves that go through them. Take note that the bushings have different sized holes and the metal sleeves are also two different sizes. The four bolts that run through these bushing were also different lengths. I had to use the longer two bolts at the actual sway bar connection.

Also, the two brake lines on the inside of the driver's side frame are held in place by a gray plastic clip snapped to the top of the frame. I had to unsnap it from the frame and shift the clip forward about half and inch to get enough clearance for the frame U bolt to fit where I placed it. Be sure to insulate the brake lines from the Ubolt so it doesn't cause any damage to it over time.

I attached the bar to the axle first and then determined the best location to mount the frame Ubolts. Last step was connecting the end-links to the sway bar ends. There are three holes on each end. I chose the stiffer setting.

If you have any additional questions, let me know and I'll try to get you an answer.

Lee Roy · February 19, 2021

My next purchase after my shocks arrive and are installed.

schmitzna · March 24, 2021

My Hellwig rear sway bar arrives tomorrow. Thanks for posting the pictures. I traded in my 2013 Silverado 2500HD Diesel for a 2021 Silverado 1500 6.2L and cannot believe how much more body roll there is on the 1500 compared to the HD. The HD springs were obviously much stiffer and that does limit body roll. Looking forward to seeing how the truck drives after I bolt this on.

Rook126 · March 24, 2021

4 hours ago, schmitzna said:

My Hellwig rear sway bar arrives tomorrow. Thanks for posting the pictures. I traded in my 2013 Silverado 2500HD Diesel for a 2021 Silverado 1500 6.2L and cannot believe how much more body roll there is on the 1500 compared to the HD. The HD springs were obviously much stiffer and that does limit body roll. Looking forward to seeing how the truck drives after I bolt this on.

As you can see from the image, I installed mine using the 3rd hole from each end of the bar. This is the stiffest setting and there are no drawbacks or regrets. The ride and suspension seem just fine. I have inspected everything a few times since the install and have not had to re-tighten anything. Feel free to ask if you have any questions on it. Good luck with you install.

Descartian · March 24, 2021

6 hours ago, schmitzna said:

My Hellwig rear sway bar arrives tomorrow. Thanks for posting the pictures. I traded in my 2013 Silverado 2500HD Diesel for a 2021 Silverado 1500 6.2L and cannot believe how much more body roll there is on the 1500 compared to the HD. The HD springs were obviously much stiffer and that does limit body roll. Looking forward to seeing how the truck drives after I bolt this on.

Let us know how it turns out.

schmitzna · March 25, 2021

I'll post another review after driving the truck but right now here are my notes with the installation fresh in my mind.

Step 2 (the very first step, actually) is a dinger. To install the U bolts over the driver side frame rail, I had to pull the left rear tire and remove the fender liner. There is a large grey plastic clip at the top of the frame rail holding the brake lines. There is very little clearance between this clip and the fuel tank and to get the U bolt to rotate in position, you actually have to slip the U-bolt under the clip to rotate it into position. Once you get the U bolt in place there is no interference, but there is no other way to get it in there. The frame rails are coated in some black sticky tar that I could only get off my hands using gasoline as a solvent. What a mess.

Step 3 (insert hourglass bushings into end links) is also a trick question. Like people mentioned, there are two sizes of bushings, sleeves, and bolts. Small bolt, sleeve and bushing for the sway bar end. Large bolt, sleeve and bushing for the clevis end. If you have an arbor press you can easily fix your mistakes here.

And I have five black washers left over that are too small for any bolt in the package. WTF are they for? The nuts that fit the bolts are both normal and lock nuts. You have more lock nuts than are called out in the instructions, so sometimes you should use a lock nut but they don't specifically say so.

All in all, the quality of the materials was top notch.

Edited March 25, 2021 by schmitzna

schmitzna · March 25, 2021

As truck mods go, I give this one a 10. Well worth the cost and the effort. I took Rook126's advice and used the stiffest setting. Now the suspension will take a set in less than half the time it took before and inspires much more confidence.

Rook126 · March 26, 2021

2 hours ago, schmitzna said:

As truck mods go, I give this one a 10. Well worth the cost and the effort. I took Rook126's advice and used the stiffest setting. Now the suspension will take a set in less than half the time it took before and inspires much more confidence.

I think I experienced the same issues you had but just didn't mention it. Sorry about that. I had the leftover black washers too. Glad you got it all figured out and are enjoying the cornering with confidence. Great job!

wewhit · April 1, 2021

I had one of these installed on my lowered '19 High Country and it made a huge difference in body roll. I traded that truck for a '21 High Country 3.0 Diesel with Adaptive Ride Control and plan to install one on this truck as well. I am glad to see that it worked well on ARC trucks, too!