The differences seem to be slight. One of these options is made for off-road adventures while the other is made for towing and hauling. Both seem to be good packages if you do one activity over the other. You may or may not find wheels that will work with both suspension packages.
The Z71 is the suspension system that is designed for off-road activities. It has monotube rear shocks that are designed to prevent damage to the suspension system. The Z85 has monotube shocks but it is designed to handle heavy loads and does not work for off-road adventures.
To learn more about this suspension system, just continue to read our article. It has the information you want to know about so you can select the right suspension system for your holiday activities. Both are good systems.
This is a simple add-on package that is designed to make towing a trailer a lot smoother and better. It is supposed to improve handling and comes with Handling/Trailering, is heavy-duty, and includes 46 mm piston monotube shocks and a 34mm front stabilizer bar.
This suspension system may increase the payload capacity but you should double-check to make sure. We checked one dealership’s 2022 Chevy Silverado 1500 and the only package mentioned in its long list of add-ons was the Z71.
We did not see any mention of the Z85 for that particular model and trim. We checked to see if the trailering package held the suspension details but it did not.
If you are wanting the Z85 for your Chevy Silverado, you may have to talk to your dealer and see what can be done. That may be because there is supposed to be very little difference between the Z71, Z60, and the Z85 packages.
Upon further research, the trailering package may be the Z85 as the trailering package was listed as the Z82 just 4 years ago.
This is probably just a suspension model number. We checked the GM Authority web page that lists all the acronyms for GM, etc., and Z85 or any Z number was not on the list provided.
According to Brickell GMC, there are 5 GM suspensions used on its vehicles. Those 5 are- Z60, NHT, Z85, Z83, AND Z71 and none of these 5 are listed either. In fact, the Brickell press release that asks the question of what does the Z60 stand for, they do not provide any answer.
They just talk about the different suspension systems and what they are designed to do. The NHT is for maximum towing capacity, and the Z83 is the standard suspension that provides a smooth ride.
Then the Z85 is mentioned as being for towing and is firmer than the other options. Finally, the Z71 is mentioned as being for off-road and comes with 18-inch wheels.
In the end, your guess is as good as ours as no one is talking about what the acronym means just what is included in the package and what it is for.
As we reported earlier, this package includes- Handling/Trailering, heavy-duty, includes 46 mm piston monotube shocks and 34mm front stabilizer bar as well as heavier springs.
It is designed to help you tow a heavier trailer and make that experience a good one. Some people mention that the Z85 may have twin tube shocks but a little later in their article, they say it is monotube shocks that are in this package.
In the manual, this package is supposed to be listed as a ‘chassis package- increased capacity’. There is not much explanation for those last two words. You should be able to tow heavier trailers and carry more weight with this package on your Silverado.
Keep in mind that the Z85 package is not designed for off-road activities. Its shock design does not seem to prevent any damage that would occur when you hit really rough terrain.
It may include the following items as one owner reported:
YD6 Base rear spring
Z85 Suspension - Increased Capacity
6ZZ - FRONT SPRING
7ZZ - FRONT SPRING
YD5 - BASE FRONT SPRING
YD3 - BASE EQUIP FOR SCH GVW PL-FT AX
G80 - LOCKING DIFFERENTIAL-REAR AXLE
GU6 - REAR AXLE 3.42 RATIO
No matter where we checked, there is no specific definition of what ‘increased capacity’ means. Logically, one would assume that those words mean that you could tow and carry more weight but that may not always be the case.
There are a lot of owners who are confused by those words and any responses to their questions do not address the question. They address other ones found in the same post.
The best thing we could advise is that you talk to your local GM or Chevy dealer and see what they say. What we have found is that there are many websites selling different parts, including eBay, that use the words ‘increased capacity’ as a selling point but offer no further explanation.
Or you can talk to a certified Chevy mechanic and have them tell you how much extra weight you can tow when you have the Z85 suspension added to your vehicle.
This is not an off-road driving suspension system. You have the Z71 if you love to go off-road and bounce your truck around the dirt and the mud. Just make sure to have good tires along with the Z71 suspension.
The Z85 suspension system, while having basically the same type of shocks as the Z71, is not made for bouncing around. The suspension is made for towing and to make sure you have better performance, a smoother ride, as well as less sway and other trailer issues.
This is an add-on package that you would have to special order through the dealer. At one point in time, about 15 years ago, it cost $95. But that is probably not the price today.
Installation costs will be higher as well. Check with your dealer before you decide to purchase to see how much this package will set you back.
Z85 is supposed to be the RPO code. If you are not sure what RPO codes are these are 3 alphanumerical codes that identify the upgrades that have been made to the vehicle. They identify the different modifications or options you have put on your vehicle at the time of purchase.
There will be times when you will find that the RPO code is part of the truck or car’s name. For example, the Silverado Z71 refers to the suspension package for off-road adventures.
You will find your vehicle’s RPO codes list somewhere in your glove box on a sticker. The Z85 code stands for in the current GM RPO List as CHASSIS PACKAGE, HIGH PAYLOAD FIRM RIDE
These RPO codes are very useful when you are needing to buy new parts. They identify the modification and make it easier to find the part number. GM has a lot of RPO codes. So much so that it fills a 104-page booklet you can find on the internet.
Just click here to get to it and you will find Z85 on the 102nd page. The Z71 suspension package is listed as ‘chassis package- off-road’. it is found on page 101.
There is really not much difference between these two chassis packages. As you can see by the RPO codes, the Z71 is for off-road driving, while the Z85 is more for towing and on-road driving.
Both are said to come with monotube shocks but the Z71 is supposed to also have skid plates. Also, the Z71 is supposed to come with the Eaton G80 locking rear differential. That is a part that is specific for off-road action.
When you are looking for tires, the Z71 is only going to be about 9/10ths of an inch taller than the tires with the Z85. Then the rear ratios are slightly different with the Z85 working with the 3.42 and the Z71 working with the 3.73.
If you want to compare rides, it is said that the Z71 is unforgiving and you will feel every bump in the road when you are driving on the highway. The same cannot be said for the Z85 as it is supposed to have a smoother ride when you are on pavement.
Keep in mind that the monotube shocks in both suspension systems, are designed differently. The Z71 protects the truck from the rough terrain while the Z85s cannot. They are designed for different purposes.
Both are good if they are used for the purposes they are designed for. The Z71 should be a bit stronger and thicker than the Z85 because it is made to work with rougher activities. Those off-road drives would damage the Z85 as it is not made for that heavy bouncing.
The Z71 can be used on the regular highway system but the ride is not made to be smooth. While some owners say they do not have a problem, other owners have reported the stiffer ride with the Z71 is very uncomfortable.
The Z85 will smooth out those bumps for you and provide a more comfortable ride until you get to those dirt roads that are not in very good condition. That is the biggest difference between the two suspension systems.
How fuel efficient they are is another story and you may get better gas mileage with the Z85 but that is not set in stone.
In some cases, you just look at the name of the truck. For example, if the name of the truck says Silverado Z71, then chances are you have the Z71 suspension package already installed.
If it doesn’t say that in the name then look around the truck. You will find decals, etc, in different places telling you that it has the Z71 suspension system. Those locations are the Z71 graphic on the instrument cluster and a special finish on the interior trim pieces, as well as the Z71 badge is also found on the grille.
Or you can look inside the glove box and check for the Z71 RPO code on the list of modifications made to the truck. The owner’s manual would also mention the suspension package you would have in your truck so you can check there if all these other locations and signs are eliminated.
You may see these different packages in the spec sheets or build your own truck option sheets. While on the surface they look like they are the same thing, they are not.
The trailering package is designed specifically to tow a trailer and nothing else behind your truck. The tow package is designed to tow just about anything behind your truck.
The latter allows you to tow other vehicles with 4 wheels on the ground while the trailering package does not. The special equipment included in both packages is not the same either.
The trailering package usually does not include any upgrades to the vehicle at all but the towing package does. Most trailering packages only come with a trailer hitch and a wiring package for the taillights.
Most tow packages come with the following equipment:
improved cooling and electrical systems
improved shocks and brakes
a sturdier frame
an upgraded alternator
When it comes to suspension systems, you want the one that is designed for the activity you will be doing most of the time. If you like going off-road and doing it often, then you should have the Z71 suspension system on your truck.
If you only like to tow a trailer to a camping spot and relax, then the Z85 is the best suspension system for that activity. Pick the one that fits your camping lifestyle.