21+ IRS SAG issues when towing product design (looking for someone in Michigan)

[steiny93]

springs (variable rate, additional), dynamic stops (Timbren's), etc

 

[martinajm]

springs (variable rate, additional), dynamic stops (Timbren's), etc

I thought that the "new" independent rear suspension on this generation of Tahoe / Yukon prevented these options. I am very interested in stiffening up my rear suspension to avoid towing sag if possible. Do you have any specific information, i.e. a link to a product, that can be added to these to address sag?

 

[jforb]

lower the front a couple inches, you'll not notice the rear sag.

but then, I'm an idiot

 

[dbphillips]

Okay, Rock Auto does have the wrong pics for those part numbers, so I got gas shocks... Looks like you need two 85521600 air springs, which are out of stock, so we're on hold until the strike ends...

 

[dbphillips]

lower the front a couple inches, you'll not notice the rear sag.

but then, I'm an idiot

Uh, until you drive it _without_ a load?

 

[dbphillips]

springs (variable rate, additional), dynamic stops (Timbren's), etc

HD springs will screw up the ride empty and looking at them, the solid height concerns me.

 

[dbphillips]

Okay, the shocks listed previously are standard fit. I found an air shock part number and ordered it, but it seems no one has them in stock, so it may be a looong while.

 

[dbphillips]

Got an air spring to test fit. Unfortunately, it replaces the spring, which would mean a complete collapse if an air spring failed. Since they are only available with Magneride, I wonder if they can only be installed with Magneride.

And I'm a little nervous about the way it seals. The spring is wide open on the bottom and it seems there are a couple seal rings that seal off on the spring perch on the shocks. Makes me wonder how it stays sealed if a tire becomes airborne. Maybe the shock limits the travel enough to maintain contact.

 

[Polo08816]

this is a terrible idea, don't tie air suspension to the tow package

gmc's air suspension is hyper unreliable in cold climates, being able to not get it is a huge plus for those of us that live where it gets cold

I'm not a fan of air suspension that completely replaces a spring.

 

[dbphillips]

Seems we just have to wait until one of the aftermarket manufacturers makes something like this:

 

[olyelr]

Seems we just have to wait until one of the aftermarket manufacturers makes something like this:

View attachment 412822

Thats a typical air shock like the pre ‘21 models had. That wont work with the new models.

 

[dbphillips]

"Like this". There doesn't appear to be a reason it couldn't be made. The fitting could be put below the spring stay, or maybe worst case, move the stay up to make room and have a shorter, stiffer spring.

 

[olyelr]

"Like this". There doesn't appear to be a reason it couldn't be made. The fitting could be put below the spring stay, or maybe worst case, move the stay up to make room and have a shorter, stiffer spring.

Gotchya, yea i get what you are saying…a typical shock/strut setup that houses the coil spring that has the air baffle option is all that is needed. Im willing to bet most of the shock manufacturers will see the importance of this on the new models and start producing them.

 

[elusive_danimal]

I posted this on another thread. But can you just buy oem magneride and air shock system and bolt it up? Are the plugs there for magnride and the air system? I know on boats that no matter what options you have the boat built with they have the plugs just sitting there ready to go. Let me know what you think!

 

[dbphillips]

I posted this on another thread. But can you just buy oem magneride and air shock system and bolt it up? Are the plugs there for magnride and the air system? I know on boats that no matter what options you have the boat built with they have the plugs just sitting there ready to go. Let me know what you think!

I feel like you didn't read the thread. You can likely do it, at great expense, but you might as well wait for a full aftermarket system. For sure, the air lines are not installed. There is a reason you hear of more owners replacing auto level systems with basic suspension components than the opposite.

Plus, there is no way I'm going to install a system that will collapse if an air spring falls.

 

[dbphillips]

Actually, I hadn't seen these springs. If the photo is accurate, they might do the trick. https://www.hdcoilsprings.com/produ...burban-tahoe-yukon-yukon-xl-rear-coil-spring/

Does anyone have any experience with the brand?

 

[olyelr]

Actually, I hadn't seen these springs. If the photo is accurate, they might do the trick. https://www.hdcoilsprings.com/produ...burban-tahoe-yukon-yukon-xl-rear-coil-spring/

Does anyone have any experience with the brand?

I dont see why they wouldnt help with towing. However, at a 35% increase in load capacity over the oem springs, i would venture to say the ride will suffer a bit…especially when unloaded/not towing.

Its an option though none the less!

 

[dbphillips]

I dont see why they wouldnt help with towing. However, at a 35% increase in load capacity over the oem springs, i would venture to say the ride will suffer a bit…especially when unloaded/not towing.

Its an option though none the less!

Yeah, barring a ringing endorsement, I'll probably try the coil Sumo spring first.

 

[olyelr]

Yeah, barring a ringing endorsement, I'll probably try the coil Sumo spring first.

Considering their price and ease of installation, i think its a product worth trying. Hell, they could even be removed if not using them for a long period of time if it happens to make the ride harsh.

 

[Polo08816]

I dont see why they wouldnt help with towing. However, at a 35% increase in load capacity over the oem springs, i would venture to say the ride will suffer a bit…especially when unloaded/not towing.

Its an option though none the less!

I think the biggest challenge is finding shocks/struts with valving that will match the increased spring rate.

While it may be a 35% increase in load capacity, it is possible that the spring rate % increase may not be nearly as much as the load capacity increase. Maybe if the spring rate is only 10-20% greater than factory, a Bilstein 5100 would be appropriate.