Sometimes it really feels like the more we learn, the less we know. In this case, it’s about the types of suspensions used in a car.
At first, we learnt that torsion beam sits at the bottom of the suspension hierarchy. A means to save cost as well as maximizing interior space.
In torsion beam setups, both sides of the axle are linked together and when one wheel goes through a bump for example, the other is affected, which disrupts the ride. Although there’s a certain degree of flexibility in the beam to improve pliancy, it’s usually a compromise between comfort and handling.
Fully independent suspension systems on the other hand, are more complex to fine tune and incur higher cost. But they are able to achieve great balance of comfort and handling whilst making the best of the available grip.
When torsion beam is compared to multi-link or double wishbone suspension, it just seems inferior. Yet some manufacturers do stand by torsion beam setups.
The French for example, doesn’t just use torsion beam suspension at the rear for entry level models. It can be found on the Peugeot 3008 and current front-wheel drive Nurburgring lap record holder, the Renault Megane RS.
Then we have Mazda, who made the controversial switch from multi-link to torsion beam in the 2019 Mazda 3. Driving enthusiasts were understandably concerned about the switch as conventional wisdom would suggest that it is a step backwards.
While Mazda did concede that on track, the limitations of a torsion beam becomes apparent as the rear axle toes in during hard corners, causing more understeer. In racing situations, multi-link suspensions would have the upper hand.
On the road though, Mazda claims the reduced number of parts in the suspension contributes to a quieter ride. It also means there are less variables to calibrate, which ties in with the new Mazda 3’s theme – simplicity.
The torsion beam used in the 2019 Mazda 3 is unlike any other, its diameter progressively thickens as it extends outwards from the middle. The patented design with thinner middle section allows greater flexibility to negate some of the drawbacks of conventional torsion beam suspension.
And the result speaks for itself, the new Mazda 3 drives as well as ever without a significant trade-off in suppleness compared to the previous generation. In fact, most of us will not be able to tell that it adopts torsion beam suspension if we were not informed.
It may appear to be a downgrade on the surface, but delve into it a little deeper and the answer may not be clear-cut. Mazda has challenged the conventional wisdom of suspension types and got us thinking, we still have much to learn.