If you’re driving a big motorhome, bus or truck, the addition of a third axle can work miracles when adding weight and stability. It’s a common discussion point for those looking to purchase a Class A motorcoach.
For RVs, the weight allowance can increase up to 20,000 extra pounds! This means larger water tanks allow you to boondock for longer periods. It also allows for features such as ceramic tile floors and residential appliances. They will just be a drop in the bucket toward that weight limit.
Let’s take a closer look at what benefits you may find with a tag axle motorhome.
What Is a Tag Axle?
A tag axle is an additional non-driven axle. It sits behind the drive axle on a motorized RV and some trucks. It ‘tags along’ on a motorhome or truck chassis, giving more support to either vehicle. This effectively allows RVs and semis to be much longer and retain stability.
In most cases, it can also increase the payload of a vehicle. So, with a tag axle, a 35′ Class A coach could easily increase its build size to 45′. It also increases the amount of cargo it can carry by 10,000 to 20,000 extra pounds depending on the coach.
When Do Vehicles Need a Tag Axle?
Most tag axles are added to a vehicle to increase its length and carrying capacity. It can also help with shock resistance and maneuverability. So motorhomes and trucks 40′ long or more could undoubtedly benefit from an additional axle. In most locations in the US the legal limit of an axle is 20,000 lbs, so if a coach needs more than that in carrying capacity, it needs another axle. Most Tag axles can carry between 10,000 and 14,000 lbs increasing the rear weight capacity significantly.
Know Before You Go: When getting a new RV, there’s a lot to know about RV weight. We uncovered The Most Important Question New RVers Don’t Ask.
Why Do Some Motorhomes Have Tag Axles?
Many motorcoaches have tag axles to provide more square footage inside the rig. They’re usually on motorhomes 40′ or longer. They also support the additional length and weight of the RV. Many tag axles can increase the cargo weight of a coach by 10,000 lbs to 20,000 lbs and add up to an additional ten feet of length.
This extra weight allows for more amenities and bigger engines. The tag can also help control a larger load when towing allowing for much higher towing capacities.
What Are the Benefits of a Tag Axle?
One of the biggest benefits of having a tag axle on a motorhome is that the coach can be more spacious, adding length and volume to the vehicle. This gives RVers more room to carry a family on a camping trip. It also offers more space to bring more toys and install bigger fresh water tanks. There is room for heavy-duty tools and even cars!
Another huge advantage is their ability to dampen shock in a motorhome. A third axle extends the wheelbase, but it also mitigates some of the bumps in rough terrain, providing a more stable ride. On our tag axle coach, the axle can be lifted and when it is off the ground, speed bumps and rocking are greatly exaggerated compared to when the axle is down.
Having a third axle also increases the surface area of contact on the road adding stability. Driving in high winds and on uneven roads with a tag axle is much more stable than without.
Today’s tag axles also have their own set of air brake drums or disc brakes, providing more safety features to the motorcoach.
What Are the Disadvantages of a Tag Axle?
The most obvious disadvantage of adding a tag axle to any coach is the extra cost of two more RV tires. These tires are also more susceptible to damage and wear out sooner because they get dragged when turning. Some coaches can remove pressure on the axle or even lift it off the ground in some RV’s. This scrubbing action can also make sharp turns harder and decrease maneuverability. Tax lift or even steering tags mitigate this problem, however, and even turn it into a pro. A bus with a lifted tag essentially has a much shorter wheel base and can turn sharper than some nontag models.
Tag axles are also another maintenance item with their own set of brakes, axle hubs, and springs or airbags. All of this costs more to maintain and increases the complexity. This also increases the likelihood of problems.
Pro Tip: Before you buy a tag axle, make sure you’re confident about What You Need to Know About Class A RVs.
What Is the Difference Between a Pusher Axle and a Tag Axle?
A pusher axle is another type of non-drive axle that is located in front of the drive axle instead of behind it. Pusher axles are much less common due to tire wear issues. They are rarely found on buses and usually only on trucks.
It’s worth noting that a tag or pusher axle is unpowered, however, some second axles are powered. Most semi-trucks and some super C motorhomes actually have a second set of powered or “live” axles. This increases traction to the ground and further increases payload as they are usually dually setups.
Is a Tag Necessary?
In some situations, a tag axle is Necessary to properly carry the weight and be within the legal limits of the road system. With lighter vehicles, they may be an option, or unnecessary.
However, don’t overlook the benefits of a tag axle motorcoach, especially if you’re considering a longer vehicle or need the extra cargo weight it can provide. The comfort of maneuverability and peace of mind you’ll have knowing that your rig is well supported will be worth upgrading. And you will have all the space you need to enjoy RV travel wherever the road will take you!
If you’re a first-time Class A motorhome buyer, you may be wondering how difficult these big rigs are to drive. Find out here: Is Driving a Class A Motorhome Hard?
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