When the existing fourth-generation Mazda 3 hatchback and sedan debuted in 2019, we praised it for being smoother and quieter than the previous model. It also received a top safety award from the IIHS, making it one of the safest family cars on the market. And Mazda did so without giving up the smooth ride and driving feel that is still characteristic of the ‘Zoom-Zoom’ car brand.
It may not seem like it, but the fourth-generation Mazda 3 is an all-new model that rides on an all-new platform and chassis. Perhaps the most significant and controversial change is the rear suspension. The outgoing third-generation Mazda 3 featured a multi-link rear suspension, an independent architecture known for its refined balance between ride comfort and sporty handling. But for the fourth-generation model, Mazda engineers have rethought and replaced the independent suspension with a torsion beam rear end.
Why is this important, you ask? Wasn’t it counterintuitive for an automaker that imbues all its cars with the “Jinba Ittai” (or “horse and rider as one”) philosophy to swap a sportier rear suspension for something as plebian as a torsion beam? In other words, how would the horse react if given the hind legs of a donkey?
Torsion beam vs. independent multi-link: what’s the catch?
The result is a tighter ride, a more comfortable ride, and the freedom for suspension engineers to dial in their preferred geometries to make the car more agile, more comfortable, or anything in between. But as with all things that sound great, there are also drawbacks. Multi-link rear suspensions have more moving parts, making them complex and expensive to design and manufacture. And because there are more “links” and bushings to connect the suspension to the body and chassis, a multi-link adds more weight and can take up more space under the car.
On the other hand, torsion beams are simpler, lighter and cheaper to produce. Torsion beams typically have an H-shaped architecture, using one trailing arm end to connect to the chassis and the other to the wheels and axles. And since torsion beams are not officially classified as independent, they lose out in terms of sporty handling and low-speed ride comfort.
On the other hand, torsion beams are cheaper to produce, which is why most cheap cars have them in the back. The question remains: why did Mazda choose torsion beams over multi-links for a car that gained a cult following for its nimble, responsive driving feel?
It’s all in the name of NVH tuning and trunk space
Torsion beams don’t have as many links or moving parts, making it easier to fine-tune ride and handling while minimizing the noise that typically comes from multi-link suspensions. And because torsion beams are simpler, more compact and tend to sit lower under the car, they free up more space in the trunk and rear, evident in the new Mazda 3’s more spacious cargo hold.
With the choice to forego tried-and-tested multi-links for the rear torsion beams, it’s easy to criticize Mazda for cutting costs in developing the fourth-generation Mazda 3. But it’s not like Mazda has thrown out a regular torsion beam and called it a day. The design is very different from the rear suspension of the now defunct Mazda CX-3 or Mazda 2, with a crossmember that is wider in the center and stamped sections at the ends to reduce rear wheel toe-in when cornering.
Apparently the results speak for themselves. There’s no denying that the new Mazda 3 drives smoother and quieter than its predecessor, but whether it’s lost some of its sporty handling during the transition can only be judged when you take it out on the track. And you probably won’t either, since the 3 is a street car.
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