Why People Dislike Torsion Beams and Why They’re Actually Not Bad | Autance

Torsion beams are mechanically simple, though they can be tricky to tune.

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Why People Dislike Torsion Beams and Why They’re Actually Not Bad | Autance © Why People Dislike Torsion Beams and Why They’re Actually Not Bad | Autance

I’ve been a terminally online car geek since well before I could drive. I used to partake in the camaraderie, debating the dynamic driving qualities of hero cars like the Mazda RX-7 or Audi RS4. “Yeah, the RS4 is an understeering pig because it’s front-heavy and trash!” Uh-huh, yeah, I didn’t know anything about understeering or how weight distribution actually affected dynamics. I mean, I was a 13-year-old kid, fresh on the cusp of puberty, never having so much as even driven a real car in a parking lot. The only driving I did, was in Forza or Gran Turismo.

Anyway, my opinions were often swayed by online discourse. That is until I finally got my own car and started driving. I quickly learned that the internet can be a fickle place, and that clandestine opinions and consensus reached in online communities don’t always reflect what’s going on in real life.

Like, does anyone remember circa 2008, the “flash to pass” debacle that “plagued” the then-new second generation Cadillac CTS? What is “flash to pass,” you might ask? It lets the signal stalk be pressed only once to quickly blink the high-beams. A lot of big-name auto mags (and their respective acolytes) kind of trashed the CTS for its lack of “flash to pass,” saying it was common on European cars where “flashing” is used to pass vehicles on the freeway, both in Europe and abroad.

But when I started driving, I noticed that no one actually “flashed to pass” on the road. Outside of a few scenarios, flashing your brights is an asshole thing to do. In cars that didn’t have the flash-to-pass, a feature that I had only learned about online, I found that quickly toggling the headlights on and off via the master switch was no big deal. I’d imagine that most drivers feel the same way. Yet, the internet would lead you to believe that this feature was something widely clamored for by the public, and that GM (and other automakers) were horrible corporations for not including it. Outside of online spaces, no one cared.

Similarly, I’ve seen similar vitriol aimed at torsion-beam rear axles, commonly called “twist-axles” in a lot of European magazines.

So, what’s a torsion-beam and why are people mad?

Twist-axles essentially comprise of a trailing arm on either side of the body, allowing independent up-and-down movement. A beam links the two trailing arms, which limits undesirable left-and-right movement, and acts as an integrated anti-roll bar. The two sides are now linked and influenced by each other, given the beam’s presence. But, the beam is deformable, it can twist, allowing quite a bit of an independent range of motion for each trailing arm. It’s an independent setup, but not quite – semi-independent, most engineers call it.

Here’s the rear axle of the European Audi A1. The crossmember connecting the two sides is hollow and flexes, allowing some independent movement between the two sides. – Image: Audi

Torsion beams are very compact, often taking much less room than a Chapman strut or multilink design axle. This usually (but not always) translates to a more spacious cabin, particularly in the back seat and trunk area. Torsion beams don’t have very many parts, which means they’re cheap to build and maintain. Cost and space efficiency is typically the reason why they’re popular on small, cheap cars where interior space and price are critical. 

The Fiat 500 has decent interior room for a short vehicle, because of its compact rear suspension design. A multilink setup doesn’t look like would fit back there. – Image: Fiat

Torsion beams do have their drawbacks, though. The range of adjustment is kind of limited compared to other suspension setups. That can make it a bit trickier to tune, especially more complicated setups where maybe a balance of ride or handling is important. Yet, there are still some great handling and riding cars that have used this suspension design.

But, for some reason, the so-called “IRS” (independent rear suspension) has become the gold standard of rear suspensions (even though it’s not being always the right tool for the job). I don’t know where we went wrong, but now torsion beams and solid axles are conflated. “Semi-independent” now means “dependent”, turbos are bad now, automatic transmissions are the enthusiast’s choice actually, left means right, up is down.

Torsion beams are independent, albeit maybe not completely independent. If you search back in the day, Volkswagen bragged about its “independent” rear suspension on its first-generation VW Golf. What was the rear suspension, you might ask? A Torsion beam. OK, maybe it’s technically “semi-independent,” but it’s not an ox-cart style, totally dependent solid axle, like what you’d find on a pickup truck or commercial van. 

Torsion-beam detractors allege that the torsion beams have no place on modern cars and that handling is significantly ruined by their presence. Sure, maybe apples to apples, a tuned “IRS” (whatever they mean by that) is likely better than a tuned torsion beam. But not everything is created equal, is it? The fastest front-wheel-drive vehicle around the Nurburgring, the Renault Megane RS, has a torsion beam rear axle. Plenty of subcompact crossovers, like the Chevy Trailblazer or Nissan Kicks, have torsion-beam rear axles, too. Millions of cars on the road, with happy owners (some enthusiasts, some not) are plodding down streets and racetracks, perfectly satisfied with their so-called “inferior” suspension setup.

So, should a torsion beam be a dealbreaker when you’re looking for your next car? I wouldn’t worry about it.

A lot of the techno nitty-gritty of how torsion beams work is probably irrelevant to most drivers. The vast majority of car owners just want something that rides or handles nicely, suspension design be damned.

I’m the same way – it doesn’t matter if it has a solid axle, or torsion beam, or “IRS” or whatever the hell else back there holding up the car’s rear wheels. Get out there and experience the car. If you like the way it drives, then who cares?

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