VW Swing Axle Vs. IRS

Classic VW models have two different types of transmissions. These include IRS and swing axles. Swing axle transmissions were used in early models, whereas IRS transmissions were used in late VW models. That does not mean that the two transmissions can’t be swapped. VW owners can upgrade their transmissions to boost efficiency and speed. A transmission rebuild can also give you great peace of mind and extend your VWs lifespan. If you are considering a transmission swap, it would be best to understand the differences between a swing axle and an IRS transmission. Knowing the differences between the two types of transmission will also help you determine the type of system your VW uses.

Whether you are considering changing your VW transmission system or are just curious, this guide will discuss everything you should know about swing axle and IRS transmission, including how they work and their differences.

What is a Swing Axle?

Swing axle transmissions were used from 1946 to 1968 on air-cooled VW bags and early-style buses. Simply put, a swing axle transmission is a rear-wheel design that allows the rear wheels to react independently to uneven road surfaces. As a result, the vehicle can maintain firm road contact and holding. Moreover, the wheels’ movement has less impact on the whole vehicle because the unsprung weight from each wheel is significantly reduced.

The first vehicle manufacturer to use the swing axle transmission was Rumpler Tropfenwagen. Other vehicle manufacturers, including Volkswagen, later adopted this type of suspension. Swing axle transmission was standard on Volkswagen Beetle and other subsequent models until 1968.

Swing axles have a center section installed rigidly on the vehicle’s chassis. Universal joints are used to connect drive axles to the center section. Since swing axles don’t have universal joints, the wheels remain perpendicular to the driveshafts. As a result, swing axle transmission is not ideal for your VWs front wheels because they require steering motion.

Most conventional swing axle suspension systems use shock absorbers and leaf springs. Swing axle was also used in early world war 1 aircraft such as Fokker and Sopwith. However, rubber bungee cords were used instead of leaf springs.

Because swing axles have thick steel tubes, they can be strong and highly durable. Unfortunately, they also have their fair share of problems. For instance, General Motors 1963 Corvair had roll-over issues due to the lack of an outer pivot. Additionally, tires are exposed to positive and negative camber when the suspension is cycled during travel. The tires will get negative camber when the car’s rear is lowered. On the other hand, the tires will have positive camber when the rear suspension is lifted.

Even so, swing axles are still popular among VW users due to the many benefits they offer. Some people love how the negative camber looks on lowered models. Let’s discuss the advantages and shortcomings of swing axles.

Swing Axle Advantages

• Reduces unsprung weight because the center of the axle is mounted on the chassis
• Extremely durable because it uses thick steel tubes
• Requires low maintenance
• Cheaper than IRS

Swing Axle Shortcomings

• Tends to wear tires quickly, especially if it is not set at the correct height
• Vulnerable to wheel camber

What is IRS?

IRS is short for Independent Rear Suspension and is a type of transmission system that allows each wheel to react to the road independently of the other wheels. Unlike a swing axle transmission, independent suspensions use axle shafts to connect the wheel to the transmission through CV joints that are mounted on each end of the driveshafts.

An independent rear suspension also has trailing arms that run diagonally from the chassis and connect near the wheel. These trailing arms provide more control, unlike swing axle suspensions that are rigidly mounted on the center section. As a result, vehicles that have an independent rear suspension experience less camber change. Most modern VW models from 1969 use the independent rear suspension system. Many car owners prefer IRS transmission because of the wheels’ ability to function independently of each other.

One wheel can absorb the vibrations caused by an uneven road without impacting the wheel’s movement on the opposite side of the axle. Moreover, an IRS system can easily navigate potholes, dips, and worn-out road sections. This makes it the ideal suspension system for daily driving and off-roading.

Advantages of Independent Rear Suspension

• Greater ride comfort
• Better traction
• Offers stability
• Reduced camber change during a suspension movement

Shortcomings of Independent Rear Suspension

• Its axle shafts are not as strong as swing axle tubes
• Require regular maintenance because they are complex
• Tend to be more pricey than swing axle systems

What are the Major Differences Between Swing Axle and Independent Rear Suspension?

The significant distinction between the two is felt when lowering your VW. The camber effect will be much more severe if your VW has a swing axle suspension system. In contrast, the camber effect will be minimal if your VW has an independent rear suspension.

Swing axle transmission is less complicated than an independent transmission. This is because swing axle transmissions use the driveshaft as the only suspension system. On the other hand, IRS uses the arm, spring plate, and suspension components. The driveshaft is only used to power the wheels.

Another significant distinction between the two is the years or compatibility. Swing axle suspension was mainly used on Beetles and other models until 1968. Independent rear suspensions, on the other hand, were introduced in 1968. As a result, most models after 1968, except 411 models, used the IRS system.

It is also vital to note that different years or models had various length torsion bars. For instance, 1958 to 1968 models that used the swing axle had 21 ¾ length torsion bars, whereas models up to 1968 had 24 9/16 torsion bars. Type 3 VWs had 24 11/16 length torsion bars, while models from 1969 had 26 9/16 length torsion bars.

What’s Better: IRS or Swing Axle?

Each transmission system offers its fair share of advantages and shortcomings. For example, swing axle suspension is known for its affordability, low maintenance requirements, and long lifespan. Because it’s cheaper, it’s a budget-friendly way to build a drag car and give it reliable power. Besides, the camber might look great on your slammed Beetle. However, it leaves your vehicle vulnerable to wheel camber and can wear tires quickly.

IRS, on the other hand, has less camber change and provides more excellent traction. In most cases, an independent rear suspension is the best choice for off-roading and on-roading activities. However, it tends to be more pricey and requires regular maintenance.

Ultimately, the suspension system you choose for your VW will depend on your budget, model, and preferences. Whether you are planning to raise or lower your VW, you will need various tools and parts, such as:

• VW rear suspension bump stop
• VW bump stop clip
• VW genuine suspension strut
• Corresponding spring plates
• Dust covers
• Spring plate bushing
• Fastener kit

Please note that changing your VW suspension system on your own is a dangerous task and should be left to the professionals. If you are shopping for the highest quality tools and accessories to lower or raise your VW, take your time to find a top-rated auto supplier shop. At Kairous Inc, we are proud to be the #1 trusted auto supply shop for top-quality vintage VW parts and accessories.