The latest Toyota Corolla has been heavily praised for its newfound dynamic zest. Suddenly, the dullest compact is one of the most satisfying to drive and part of that is due to its trick new double-wishbone independent rear suspension. Where the Corolla hatch may have missed the mark, however, is in its reduced cargo volume. Whether it be for these packaging considerations or simply due to cost, the rest of the segment, including the Mazda3 (above) and Mercedes A-Class, are actually moving partially or entirely away from independent rear suspension. This leaves the Corolla in a shrinking pool of IRS-equipped offerings.
For those unfamiliar with the term, a torsion beam rear suspension uses trailing arms integrated with a crossmember. This is designed to twist as the wheels move, hence why a torsion beam is often referred to as a twist-beam. In short, it’s more sophisticated than a traditional live rear axle but less sophisticated than independent rear suspension. The crossmember can be mounted down quite low, aiding cabin and cargo space, and the set-up is simpler than IRS, often relatively light, and the cross-member also serves as an anti-roll bar.
Mazda, Ford and Mercedes-Benz are the latest brands to switch from IRS to a torsion beam. Mazda’s decision to ditch IRS is at odds with the Mazda3’s more upmarket positioning. In the US, for example, the cheapest Mazda3 now costs $3k more than its predecessor. And though the torsion beam seems to be a cost-cutting move, the new 3’s interior has been thoroughly transformed for the new generation and is richly-appointed with an abundance of high-quality materials.
Though a torsion beam sits nice and low and should therefore improve cargo volume, the new Mazda3 hatch actually sees a slight reduction in trunk space. Mazda has defended the shift to the beam, claiming there are fewer variables when engineering a torsion beam and therefore it’s easier to engineer and fine-tune. They’ve also claimed the switch has helped reduce the Mazda3’s NVH levels which, based on reviews of the new generation, seems to have worked. Few automotive journalists have noticed an appreciable decline in dynamic ability, either.
Another dynamic benchmark in this segment, the Ford Focus, now uses a torsion beam in most models. The smaller Fiesta had always used a torsion beam, even in snappy ST trim. The new Focus has a multi-link “Short Long Arm” rear suspension in all wagon variants and a slightly different version of the system in sports variants. The wagons’ suspension has the dampers sitting nearly horizontal, allowing for more cargo space.
Most Focuses, however, will have the torsion beam, which seems like a step backwards although it does use some of the same parts as the Fiesta ST. In comparing the Focus’ IRS and beam set-ups, Drive found the torsion beam-equipped models still handled excellently but, compared to the IRS models, experienced slight vibration and shake on rough roads. So, there’s not a marked decline in ride comfort and virtually nothing in handling ability. Still, one wonders why Ford didn’t just use the wagon’s IRS in the less powerful hatch models instead of engineering three separate rear suspension set-ups.
Ford C2 architecture chief engineer Michael Blischke went so far as to say Ford only held back from switching the Focus entirely to torsion-beam because of the Focus’ entrenched reputation for dynamic excellence. While that sounds like a humble brag, he explained Chinese buyers in particular value the latest in technology and innovation. Considering Ford’s somewhat shaky situation in Europe and even worse footing in China, retaining the IRS was sensible even if, as Blischke explained, a torsion-beam is arguably fine for 95% of drivers.
GM had already utilized this semi-independent suspension layout in the outgoing Chevrolet Cruze and the now PSA-owned Opel Astra. When PSA launches the next Astra generation – likely to share a platform with the Peugeot 308 – they’ll probably stick with this layout as Peugeot’s 308 also employs it. The same applied to the defunct Citroen C4 and the C4 Cactus, likely to be merged into one model in the near-future. Nissan is another company that’s consistently stuck with the beam, ditching its short-lived IRS from the Sentra in ’95 and not looking back. Partner Renault also uses a torsion beam set-up in the Megane.
Mercedes’ new A-Class has a torsion beam in models at the low end of the range. Mercedes’ compact car development engineer, Frank Weiner (I never sausage an interesting name!), cited the common refrain of the torsion beam set-up’s weight and packaging advantages but also highlighted the need to future-proof the A-Class platform for electrification.
The new A-Class’ program manager, Oliver Zolke, told GoAuto the change was driven by the weight reduction available with the torsion beam. The total weight saving? 44 pounds. That doesn’t seem that impressive but Zolke went on to say this freed the engineers up to do some extra stiffening and stretch the wheelbase. Zolke also believes the torsion beam set-up allows for greater ride comfort so make of all this what you will.
Like Mercedes and Ford, Hyundai and Kia offer IRS only in sportier versions of its Elantra, i30 and Forte/Cerato compacts. Though the Elantra’s trunk volume is the same size regardless of suspension set-up, the IRS models have a space-saver spare while the torsion beam models have a full-size one. The dynamic divide between the two suspension set-ups seems to be more apparent in the Hyundais, critics generally finding the IRS models to ride and handle better. Perhaps because of this, the European Ceed, related to the Forte/Cerato, is IRS-only.
This widespread return to torsion beams in the compact segment seems to be a historical correction. Volkswagen only switched to IRS with the Mk5 Golf, coming shortly after the first Ford Focus and its Control Blade IRS; the current Golf range features IRS in some models, torsion beam in others. Of VW’s other C-segment offerings, all on the MQB architecture, there’s one that exclusively uses torsion beam (Skoda Scala), one that uses it only on base models in some markets (Audi A3), and two that use it on all bar sporty trim levels (Seat Leon, VW Jetta).
Honda is somewhat of an outlier here, exclusively using IRS on the current Civic. Alfa Romeo switched to IRS with the 2000 147 and the Giulietta retains that set-up, while the Subaru Impreza is also equipped with IRS.
Whether it’s to eke out a little bit more trunk volume or (more likely) to save money, IRS is rapidly disappearing from the compact segment right as Toyota introduces a new Corolla with it. Has Toyota misjudged compact buyers’ expectations? Is the promise of a slightly smoother ride and better handling at the limit worth a reduction in cargo volume? Though the less sophisticated beam arrangement is anathema to enthusiasts and smacks of cost-cutting, compacts equipped with the torsion beam don’t seem to be demonstrably disadvantaged dynamically. It’s possible to engineer a car to ride and handle commendably with such a set-up. If you insist on IRS, however, be prepared to pony up for up-level variants. Or just buy a Civic or Corolla.
Related Reading:
“Here’s Why The 2020 Mazda3 Has A Torsion-Beam Rear Suspension” – Craig Cole, AutoGuide
“Benz defends A-Class switch to torsion beam rear end” – Daniel DeGasperi, GoAuto
“New Benz A-Class hybrid drove torsion beam” – Byron Mathioudakis, GoAuto
“Ford Focus 2019 review” – Alex Rae, Drive
“Why most Ford Focus models ditch IRS” – Byron Mathioudakis, GoAuto
The SAAB c900 suspension, with two Watts links and a panhard rod seems like a good compromise, and allows for some amount of passive rear steer.
“Though the less sophisticated beam arrangement is anathema to enthusiasts and smacks of cost-cutting, compacts equipped with the torsion beam don’t seem to be demonstrably disadvantaged dynamically. It’s possible to engineer a car to ride and handle commendably with such a set-up.”
I have a strong suspicion that 90% or more of automotive “journalists” wouldn’t be able to tell the difference between an IRS and a good twist beam in a blinded experiment. Much as professional wine tasters have been shown to be essentially useless and inconsistent in their proclamations.
I’d also love to see what happens to their reviews when they have no idea what car company made the vehicle they are testing, or even better–if you could make them believe it was a different model. Wrap a Civic in Cruze sheet metal and a transplanted interior and see what happens.
I have to agree with you. Most “experts” are no more an expert than you or I; they simply have a job writing for some automotive media group.
The analogy with wine experts is spot on. With 90% in the cost of a wine dependent on packaging and marketing, the experts are there to help justify why one should choose brand A over brand B. Oakey? Hints of vanilla? Or perhaps caribou excrement? Really? To some, you may be able to discern, but most people just taste grape juice gone so bad it’s good again.
If they had an objective test to identify those who can manage telling fine differences in ride and handling, then I would believe the expert’s opinions would carry some weight. Since that isn’t happening, it’s about as good as my co-workers telling me that the ride on their car is better than mine.
Having read a lot of reviews as well as comments over the years, I’m going to side with the professional reviewers. They spend a lot more time in all/many of the comparable vehicles in order to experience their differences and formulate a judgement. That’s not to say that I take their reviews without applying my own BS filter. And some are much better than others.
As to opinions by non-pros, I have found their abilities and judgement to be profoundly variable, as is the content of their comments. Some are exceptional, better than many pros. Others not so much so, to put it lightly. I’ve been reading comments for way too long… 🙂
I find the quality to be profoundly variable by all reviewers, professional and amateur. The thing is, even reviewers that are very good at their job tend to nitpick things that nobody would ever notice or car about unless told about it.
That’s precisely their job. What readers do with that information is up to them.
I agree with Paul on this.
I find some enthusiasts accuse automotive journalists of being paid shills, others accuse them of being excessively nitpicky and, bewilderingly, others accuse them of both.
There can’t be an objective test for ride, handling, ergonomics etc because one doesn’t exist. For the same reason you step into a car and appreciate the “feel” of it and like the way it drives, so too do automotive journalists often come to the same conclusion about a car. And if you’re wondering why, say, your Corolla loses in a comparison test to, say, a Civic, keep in mind these guys and girls get paid to drive new cars for a living. They’ve probably driven both. And the rest of the segment.
I also agree with Paul. And why are we dissing wine reviewers? I know a master sommelier, he can sip a wine and tell you where it’s from and it’s year. It’s objective not subjective. Now book or music reviewers, that’s another story.
Only because there have been several objective studies demonstrating inconsistency in wine tasters’s expertise, which makes it a pretty good analogy to the field of automotive journalism. Your friend may well be one of the good ones, much as there are some autojournos whose judgement I would trust. I could have used the stock picking cat instead, I suppose 🙂
Yes, it is their job. However modern journalists, and I use that term loosely, tend to focus on a lot of things that most people would not care about if it was not brought up and ignore practical considerations. This has shaped the way vehicles have evolved.
The same thing happened in cell phones, which lead to impractical designs like fragile and slippery glass and/or metal backs. I see this now with hatchbacks with no more usable cargo space than sedans, punishing ride quality, and rear seats that cannot accommodate 3 kids in child seats. Another example is that few GM vehicles put 3 head restraints in the rear bench seats of their supposed family vehicles, which was a dealbreaker when I was looking at CUVs and pickups. Or the shoulder belts in the 3rd row of the last generation Chrysler minivans that are mounted so far forward the belt doesn’t touch your shoulder. These things are almost never mentioned by “professional” reviewers who are more concerned about a couple of extra ticks to 60 MPH, or about the amount of soft touch materials in places that are never touched. It’s made them next to worthless for me.
Not all of them are like that, but in my opinion the majority are today. It’s why I have enjoyed Jim’s rental reviews here, they are a breath of fresh air.
Torsion beam rear suspension will never beat IRS for handing and ride comfort. This trend of IRS vs torsion beam has been going back and forth since the 80s. OEMs will switch to torsion beam to save $$$ then switch back to match or try to beat the competition. Look at the Nissan Maxima. It went from IRS to torsion beam back to IRS. When the torsion beam maxima came out in 95 magazines hailed it as revolutionary, a torsion beam setup that can match an IRS….no the ride was punishingly harsh. That’s the problem with torsion beam. To match the handling of IRS you need super stiff springs which ruin the ride, even with high sidewall tires. Make the springs softer and you have a boaty ride. Perfect example is the late 90s gm N body. Pontiac used soft springs for the grand am while olds used stiff springs for the achieva to give it better handling. The result, the GA felt like a boat wile the achieva felt like it had no suspension at all. No happy middle ground and the 99 redesign which gave it an IRS fixed that.
anyway I’ll always choose the car with IRS. Mazda is not an enthusiasts brand.
Nissan put fluid-filled bushings in the trailing arms of those torsion beam maximas in an attempt to help a bit with ride quality and NVH, the problem is after 7-10 years that fluid leaked out, and there is no way to replace those bushings other than buying the entire rear beam assembly from Nissan. I can confirm that the ride quality of my ’00 Maxima, with fresh Monroe QuickStruts was very mediocre. My ’96 Lexus on original 209k mile struts was much more comfortable.
I had a 97 maxima and my mom had a 95 gxe and brother had 95 se, and I don’t remember the ride being harsh, and certainly not punishingly harsh.
I also had a saab 900 and loved the suspension.
It’s all relative I suppose. I think the Nissans are stiffer sprung to begin with, certainly a much more fun to drive car than the cushy Lexus.
” Mazda is not an enthusiasts brand.”
What planet are you from ?
Maybe they once were. Now They’re not. They have the mx5 and that’s it. No stick shift in the 6 anymore, no IRS in in the 3.If you want front wheel drive why buy any mazda when Honda gives you a stick in the accord and civic with any engine.
Where I live, there is NO Accord anymore, and stick shift 6s are no problem.
So by your logic, Ferrari isn’t an enthusiast brand because they don’t offer conventional manual transmissions anymore.
Riiiiightt….
Compare the 2008 mazda lineup to today and then see whats become of mazda as an “enthusiast” brand.
The fact they learned..just as mitsubishi learned before …enthusiast marketing and products dont equate to sales. Hence why the speed6 died speed3 gone stick shifts gone irs leavinf and theyre marketting themselves as an upmatket brand now.
Ok, the Mazdaspeed line and RX-8 are gone. But their cars, even their crossovers, remain more fun-to-drive than most rivals and the company seems to prioritize weight reduction and driving dynamics more than others. I don’t know what your definition of an “enthusiast” brand is but I’m struggling to figure out what brand would meet your criteria.
British car mags heavily criticised the Mk4 Golf for its’ torsion beam, at a time when the Focus was IRS. My son bought himself an early A3 Sport, which was basically a lowered Golf in a fancy dress, and the chassis was superb.
I also had a 2003 GTI and loved the suspension;-)
“In short, it’s more sophisticated than a traditional live rear axle but less sophisticated than independent rear suspension.”
A twist beam is not more sophisticated than a live axle. The live axle is far more “sophisticated” since it is driven and has to account for the drive torque. If you want to say it is more sophisticated than a buggy spring dead axle then yeah.
Reduced assembly labor cost is probably another driving factor behind the revival of the twist-beam rear suspension, which was used in the 1982 Chrysler K-cars, presumably for economy. It proved useful in mimivans, where the space-saving over a strut-based rear suspension was important.
As for what the mass-market journalists write, since their salaries are paid by advertisers wanting to perpetuate their public perception, look to see them tout the products of those who buy the flashiest prime-placement advertising spreads. They bend with the flow of money, just as the twist-beam does with a one-wheel bump inthe road.
The Chrysler minivans used a solid beam axle with leaf springs, at least through 2008.
“Cheaper” intrinsically implies materials and labor, in the auto industry.
Yes up until 2008 the Mopar vans used a leaf sprung rear beam, nothing torsion about it. 2008+, yes torsion beam rear end.
“As for what the mass-market journalists write, since their salaries are paid by advertisers wanting to perpetuate their public perception, look to see them tout the products of those who buy the flashiest prime-placement advertising spreads. They bend with the flow of money, just as the twist-beam does with a one-wheel bump inthe road“.
That is simply not true. An awful generalisation at best.
Agreed. But some folks want to believe that, and nothing will change their minds.
Having met automotive journalists and read plenty of high-quality and impartial work by them, I find G. Poon’s comments frustrating.
I suspect a lot of the performance (handling, ride, NVH) is in the execution, not the basic technology. And, to be a nit-picker, I suspect none of these IRS designs are truly independent, as they have a torsion bar, aka anti-roll bar, connecting the two sides. And a torsion beam is not really solid, hence it is a form of IRS. In fact I seem to recall that the original Golf, which I think was the first volume production car to use this design, was described as having semi-independent suspension. Finally, as Scoutdude noted, a live axle is a driven axle, and these FWD cars have dead axles in the rear, or perhaps solid axles. But to heck with the suspension, I like that Focus wagon. I’ll take mine with a diesel, please!
Toyota specifically said that they could afford to use IRS on the new Corolla because of two reasons: the new TNGA modular “platform” is cheaper and also lighter, so the weight and money saved went into a better rear suspension. A pretty strong move by Toyota to strengthen the Corolla’s (and Prius/Camry/etc.) dynamic qualities. Ride is improved too, since Toyota focused on removing friction out of the suspension, which is a key impediment to a better ride.
A welcome return. Toyota used the “classic” multi-link IRS on corollas since the late 80s (starting with the ’88 in US iirc?), that lasted until the redesigned ’03 body style, that went to a cheap torsion beam. I wonder if the new wishbone setup will be as durable as the tried and true multi-link.
Rear struts multilink. This is perhaps hairsplitting because a rear MacPherson strut does typically use links (normally one trailing and one lateral, sometimes two lateral) to locate the strut, but rear struts have their own geometric limitations.
Toyota DID have a fascinating, complicated, very expensive multilink strut suspension, Super Strut, which was available on non-U.S. Corollas (et al), but that was a front-end setup.
Playing with different rear suspension setups makes a lot of sense to me, an excellent example of a component that can save space, cost and weight and that the huge majority of consumers won’t care about.
Count me among the rubes who can’t tell the difference. My Integra had IRS, and I honestly couldn’t tell you that it rode or handled any better *in my usage*.
I consider a torsion beam to be similar to rear drum brakes. Car reviewers (and every commenter on the Internet) say “OMG this car has rear drum brakes! How cheap and horrible!” when in fact, they do the job just fine on a FWD compact or subcompact.
99% of car buyers don’t care if the car they’re looking at has a torsion beam or rear drum brakes. They just want to see the price tag, and both of those things make a car cheaper.
I’m of two minds:
Drum brakes: sure I’ll gladly take them. They don’t rust out like disks do in the salt belt, basically zero maintenance needed for 150k miles (or more).
Torsion beam suspensions: fewer bushings to go bad, fewer balljoints to get loose. But IMO they do ride worse. Not to say all torsion beam cars all ride poorly, just that everything else being equal, the IRS has a define and discernible edge. And as I learned with the Maxima, when certain bushings DO go bad on the torsion beam rear end, things can actually be more difficult and more expensive to correct than on an IRS (comparing fluid filled bushings leaking out by 100k to Lexus/Toyota rear multi-link with no discernible bushing wear after 23 years and 209k miles).
I’m not being argumentative but is it possible that someone changed/replaced the Lexus bushings prior to your ownership, say at 150k miles? I’d be surprised if the rubber or whatever material was used had zero degradation over 23 years of age and weather. Of course it is possible that the factory marked the install somehow that made it obvious it was in fact the original parts and yes, rear suspension bushings are generally not on most american driver’s mind to replace. But still, a Lexus, even the ES, is more likely to get more ongoing maintenance than a Cobalt for example.
Where will a true IRS be superior to a twist beam ? On the track, where you can adjust camber and toe-in with IRS – even if you have to buy special adjustable parts.
On the road, if you’re not on a highway/motorway which is mostly straight and smooth , then you’re either restricted by speed limits or by the need to be able to avoid pot-holes/ pedestrians/cyclists/cats/dogs/donkeys/cattle etc. (pheasants have absolutely no road sense whatsoever).
Only motoring journalists have the luxury of being able to test cars to the limit.
Torsion beams tend to be a little more “crashy” when the going gets rough, such as over potholes or poorly maintained roads. However, torsion-beam setups also have far fewer things to go wrong and are less likely to get torn up on those bad roads.
Not so. How many folks are going to adjust their camber or toe-in for the track? A tiny handful. You think Toyota decided to standardize on IRS with their millions of cars built on their TNGA platform (Corolla, prius, Camry, Rav4, and others) because of the possibility of doing that?
They did it because it’s possible to reduce friction more on an IRS than a twist beam, and reduced friction is the secret sauce to a better ride over expansion joints, potholes and other sharp pavement breaks and such, as well as adhering better to road imperfections at speed in a curve. IRS really, truly is intrinsically better at both ride and handling. Obviously, some/many torsion beam suspension are set up to handle very well, but I’m convinced that it’s never going to be able to do both as well as a good IRS.
Why else would Toyota be doing this? And with their brutal cost controls, they can afford to.
Every manufacturer would also use IRS if they could afford to. But they’re perpetually yo-yoing on cost versus performance.
I think Toyota always used IRS on premium Corolla variants. They have standardised it for perceived quality purposes. Perception is everything. Many folk buy Volvos because they think they are safer. Many buy VWs and Audis because they think they are better made.
I don’t buy Volvos or VWs or cars with twist beam suspension, but then I’m a petrolhead.
My current Accord/TSX has five-link IRS. That’s ten bushes each side, which must have more friction than a simple twist beam – but that’s a luxury I can afford.
They put IRS on the European versions, like the Auris, because the European market had higher standards for ride and handling.
They’re not doing it for “perceived quality purposes”. Quality and reliability are not really in this equation. They’re doing it to improve the perception of Toyotas as fun-to-drive, contrary to the common perception of them, in the US anyway.
So you know more about reducing friction in a suspension than Toyota? 🙂
I think the bottom line is that automakers who put more of an emphasis on vehicles with above average ride and handling characteristics (Ford, Mazda, et al.) also have the expertise to engineer a torsion beam setup that doesn’t compromise anything when compared to an IRS system.
I think the bottom line is…
Your rather obvious Ford bias is showing by saying this. 🙂
And no, it’s not that simple. A proper multi-link IRS has a greater ability to control wheel geometry more favorably in various situations, especially the more extreme ones.
I doubt you’d get any suspension engineer to not agree that multi-link IRS is inherently better, and that the only reason companies keep reverting (or keeping) twist beam is cost, pure and simple. And if they can get it to satisfy the great majority of drivers, why not?
Why else would VW, for instance, use IRS on their top end versions of the Golf family if what you said was true? Why bother with the extra production complexity and cost? VW is brutal about limiting variations to keep costs down.
I’ve read the relevant copy on the Toyota website and I don’t think it was penned by Toyota suspension engineers….
You can adjust camber and toe in on a torsion beam suspension by using available shims which are installed under the stub axle. These shims are commonly used for 4 wheel alignments.
https://www.google.com/url?sa=t&source=web&rct=j&url=http://www.lellaautosport.com/alignment-shim.html&ved=2ahUKEwjywo6s-r7iAhXjHjQIHTb8AJQQFjALegQIARAB&usg=AOvVaw0dpm764oEWyZhpXlQYVgDp
As I recall, the Golf, Golf Alltrack and Golf SportWagen have IRS. But diesel versions, here in the ‘States, had the torsion-beam setup because it freed up space for the DEF tank. Since I had a ’15 Golf SportWagen TDI, mine had the torsion beam. I did not notice a difference between it and my Jetta SportWagen, which had IRS (and no DEF tank).
I’m glad to know someone else can tell the difference. 🙂
I bought my Golf over the Jetta for a few reasons, but one was the Golf has a sophisticated IRS system. The Golf simply handles rough roads better and especially mid-corner bumps.
That’s not to say a torsion beam is a deal breaker. My Rio had the torsion beam system and it was fine like 90% of the time. Only very occasionally over a larger bump at higher speeds could I feel the most minor of side steps in the rear.
Hyundai is sticking with torsion beam for its cars, which still sell on price and financing, at least in the Canadian market. I highly doubt the vast majority of drivers would even notice the difference.
That said, we have come a long, long way. My Hot Rod Lincoln has a good old fashioned solid axle on coil springs. Any kind of rough road sends the rear dancing all over the place and I have really upgraded the suspension in it.
Torsion beams may be more controversial than vaccinations.
I’m weary of this trend. At least from personal taste, I’ll always sacrifice a tiny bit interior/cargo volume for the sake of better handling.
Citroen wiped the floor in the 98 WRC using a torsion bar rear axle and FWD, the high speed handling on rough roads of my Xsara was unsurpassed and the comfort levels were pretty good too, the entire rear axle less wheels weighs only 50kg and is easy to swap out when not if the needle rollers in the swing arms fail, the axle is mounted on soft bushings to provide passive rear steer which works brilliantly, with two semi panhard rods added it was used in the 307/C4 range and from experience C4s handle and ride beautifully, I would happily downgrade from hydra-active to one of those should the need occur.
Typically, torsion beam means more unsprung weight. Unsprung weight is the amount of weight directly connected to the wheels, rather than supported by the spring components of the suspension. The rule of thumb, is that more unsprung mass is the enemy of handling and ride quality, thus the move towards lighter wheels, composite brake components and spindles made from “unobtainium” in exotic cars and racing vehicles.
But sometimes, IRS vehicles don’t handle particularly well – 1st Gen Chevy Corvair, Mercedes 300SL’s, early Porsche 911s. And then, sometimes so-called solid axle cars are decently sorted…Mustangs, Camaros, Fiesta ST’s.
We just happen to have two torsion beam vehicles at the moment, a 17 Kia Soul and a 15 Fiesta. Our first IRS car was a 91 Protege, and the last was an 06 Civic. Both of which handled rough roads wonderfully, the Civic was waaaay less fun in the twisties due to 15 more years of flab. Now the Soul is a utilitarian ride, built to put s*#& in, and be unobtrusive. The Fiesta, with a sport package that includes former bushings in the front, lightweight wheels and performance tires all around, is a totally tossable little car. It handles as well as any B-Spec car, and only loses a slight bit of ride quality in the rear over the choppier roads.
Conclusion, IRS doesn’t always trump. And torsion beam doesn’t always suck. Unless it is a GM J-body, or a Kcar.
Agreed. Sister’s first car was an ’09 Soul, and riding in back, yes you could tell. Her best friends similar age Sportage was noticeable in that it had less crash and jar. Overall though? Minute, especially if you rode in front. Both were cheap. It’s not on any buyer’s radar at 20k.
It’s an interesting one, for sure. As bryce points out, PSA made a superb torsion beam, with the cars (205, 305, 405, Xsara) rightly praised above all others in their respective classes in their time for handling excellence. I’ve had a good go in Pugs 405 and 306 and they were indeed first rate. So it can be done really well.
That said, the Renault I had (Megane) was only adequate, acceptable enough but as with all non-IRS, the big failure is mid-corner bumps, of which this country has a variety and constancy such that they must be engineered into the roadbuilder’s job spec. Barrelling down the same bumpy and twisty 60mph road with daily regularity in a Honda then the Renault in turn – something I was doing three or more times a day till about a year ago – showed the difference keenly. The Frog, in true Euro tradition, had the better damped plusher-travel ride in a straight (bumpy) line, but there was no way you’d push it as hard round these bends, because ultimately it would leap sideways.
I have no doubt motoring journos who, after all, are driving for the purpose of noticing stuff would have no difficulty picking it up. And it’s a meaningful real-world difference, because you are simply tossed around more with non-IRS and there’s more potential for trouble if a corner tightens up and is bumpy (a common enough combination).
I’ve said here before that the motoring press has had a goodly role in improving the breed of cars generally over the past 50 years, demanding more and better (often by testing on limits) with results that have benefitted all. For sure, you learn which journalists or publications to trust more than others, but some of the comments made about the press above are just inane cliches.
” PSA made a superb torsion beam, with the cars (205, 305, 405,”
These Peugeots had proper trailing arm IRS, not a twist-beam.
I’m going to attempt to disagree, Uncle M, albeit I’m not an engineer. Everyone refers to it as a torsion beam (which is ofcourse no proof of anything) and the trailing arms appear to be attached solidly to the stout cross beam under the car. It’s complicated by the fact that the torsion bar springing is mounted to the same beam (making for a cleverly compact unit, also in the Renault I had).
Where I can’t quite work it out is that there are bearings inside the hollow beam for the trailing arm connection, which could be connected to an internal cross beam OR the trailing arm connections don’t go all the way across internally – which would make it sort-of independent (“sort of” because of the way the torsion bar springs seems to be mounted).
In any case, it’s a much cheaper system than multi-linked IRS, and very compact.
Also, if it’s going to turn up to the party dressed as a torsion beam, it shouldn’t complain when it’s mistaken for one.
The only bearings in a twist beam are the wheel bearings. The cross beam is not fixed to the chassis at all, only connects the arms. Coil spring and damper at the wheel end of each arm, rubber mounting bush at the chassis end.
In their heyday, Peugeot were renowned for very fine suspensions, even making their own dampers. Any of their engineers saying the words “twist beam” would have been forced to wash his mouth out – such a system was far too crude for them.
Yes my C5 has the same but with spheres instead of steel springs its the smaller 306 ZX Xsaras that had torsion bars mounted tothe axle tube the needle rollers where the trailing arm mounts to pivot
wear and collapse kits are available changing the bearings is like doing VW front beams good used axles are easier to swap in and a lot cheaper, I have a photo of the beam I changed on my Xsara but of course it wont load to show how it works
In the current regulatory environment in the US where fuel mileage numbers are the holy grail, anything that can reduce weight is good. If the torsion beam weighs less than IRS, then it will have the inside lane here. That it is also cheaper is just a bonus.
I am probably in the majority when I opine that Good IRS > Good TB, while Good TB > Bad IRS.
Could be. The F-150 shows the great lengths Ford has gone to for increased economy. Direct-injected twin turbo, aluminum body, active grill shutters, auto stop/start, wheel ducts, 10 speed transmission, etc. A lot of added cost and complexity. I have no doubt most of this will negatively affect reliability and repair costs down the road.
I’m extremely skeptical of any argument for torsion beams that isn’t talking about cost and packaging — it’s like drum brakes, which have certain advantages, but not in performance. It’s not coincidental that even on modern cars that have both IRS and torsion beam options, the former is commonly found on the more powerful sporty versions.
That said, the most important factor in achieving the best ride and handling from a given package is selecting the optimum marriage of spring rates (vertical and anti-roll), damping, bushing rates, and tires. This is challenging to achieve and is often compromised by cost, aesthetic, and/or performative factors. For instance, a sporty model might end up with springs that are really too stiff and tires that are too big because the suspension engineers lost the argument with the product planners and marketing people that sporty should mean lower, stiffer, with the biggest contact patch possible, which is seldom true.
Don’t mention drum brakes! Evil leaking grabbing maladjusted uneven-wearing overheating ineffective finger-ripping overweight misfits from the iron age, and a menace to society. Fitted today only because of the malign influence of some dullard greasy-pole-climbing accountant seeking promotion by proving he saved $20 on production costs.
There, that always feels better out.
To the topic at hand: I don’t disagree that the cousin of the abovementioned accountant in marketing imposes stupidities on the honest suspension engineer, but I can’t agree that tuning alone is all. The ways in which that wheel can be kept square to the road during the huge and varying demands placed on it geometrically – while keeping decent compliance – is the most important factor, hence the proliferation of complex multilink systems. Well, “proliferation” until the brutality of the car business has begun to delete them as a sophistry we don’t need. Presumably, they also consult the ambitious accountant who calculates actuarily that ESP et al will save us when the dumber suspensions don’t cope in those unexpected moments.