Can Mazda be saved????

[FoMoJo]

Floating, as not attached to the body/frame/platform.  As for unsprung weight, the entire weight of the beam being lifted as opposed to multi-link suspension rods simply being pivoted.  As for the dynamics, sway bars are attached to the end point where lift is easier; like lifting a beam on the end rather than in the middle.  Not a clear description, but you should understand.

[MX793]

Floating, as not attached to the body/frame/platform.  As for unsprung weight, the entire weight of the beam being lifted as opposed to multi-link suspension rods simply being pivoted.  As for the dynamics, sway bars are attached to the end point where lift is easier; like lifting a beam on the end rather than in the middle.  Not a clear description, but you should understand.

I think you are assuming that a torsion beam is like a dead axle, where you have this great mass largely connected by the springs with a few links to keep it pointed in the correct direction.  The torsion beam is just behind the trailing arm pivots, which are attached to the chassis.  The beam and trailing arms combined sort of make up one big wishbone with a pivot at the chassis and the wheels and shocks and springs attached at the ends.  Much like the links in a multi-link, this entire "wishbone" pivots rather than fully floats.  If the suspension moves an inch, the torsion beam itself might only move 1/4".

[2o6]

I just think it's crazy and annoying that now people are poo-pooing twist axles when 18 months ago no one knew what they were or cared.

I don't think people "notice" as much as they say they do.


Torsion beams are independent enough.

[MX793]

I just think it's crazy and annoying that now people are poo-pooing twist axles when 18 months ago no one knew what they were or cared.

I don't think people "notice" as much as they say they do.


Torsion beams are independent enough.

I think most people hear "beam" and assume it's the same as or very much like a live (or dead for a FWD) rear axle.  Which it's not.  Just like people hear "leaf spring" in the Corvette and assume it's got the same sort of suspension you'd find under a horse-drawn wagon from the 18th century.  Or a pickup truck.

[r0tor]

Not sure what is going on here.  Yea you can say the twist beam is similar to a sway bar - but an overly stiff sway bar.     When you get a really stiff sway bar the motions are not controlled well by the shocks and the suspension skips over rough patches of road during cornering - pretty much as described.

[12,000 RPM]

I just think it's crazy and annoying that now people are poo-pooing twist axles when 18 months ago no one knew what they were or cared.

I don't think people "notice" as much as they say they do.


Torsion beams are independent enough.

It's just a weird move for a company thats prided itself on being "driver focused" and is making an upmarket push. Do torsion beams work? Of course. Do they work as well as a well designed true IRS? Hell no. Do details like that matter in a car billed as premium? I'd say yes.

[FoMoJo]

I think you are assuming that a torsion beam is like a dead axle, where you have this great mass largely connected by the springs with a few links to keep it pointed in the correct direction.  The torsion beam is just behind the trailing arm pivots, which are attached to the chassis.  The beam and trailing arms combined sort of make up one big wishbone with a pivot at the chassis and the wheels and shocks and springs attached at the ends.  Much like the links in a multi-link, this entire "wishbone" pivots rather than fully floats.  If the suspension moves an inch, the torsion beam itself might only move 1/4".

No, I understand the dynamics of a torsion/twist beam suspension vs. multi-link.  There is certainly enough information on the web, as well as graphics to illustrate just about everything.  Torsion beam has the advantage of being more economical and it is well understood that most people would never detect a difference in their normal daily driving.  For that matter, there is likely very little difference in normal driving.

However, Mazda has always prided itself on it's 'handling' dynamics.  When designing the rear suspension for the Gen I Mazda 6 (Atenza), Mazda called on the expertise of a engineer largely responsible for the design of the Mondeo Gen II, which uses a related platform, in order to help design a unique rear suspension for the Mazda 6 (Atenza).  Slapping in a twist beam on the new Mazda 3 seems like a indication that Mazda has given up on their Zoom Zoom handling dynamics that Mazda prided itself on.

[MX793]

Not sure what is going on here.  Yea you can say the twist beam is similar to a sway bar - but an overly stiff sway bar.     When you get a really stiff sway bar the motions are not controlled well by the shocks and the suspension skips over rough patches of road during cornering - pretty much as described.

Many cars with torsion beams have a (small) sway bar in addition, meaning that the torsion beam alone does not necessarily provide the same level of roll stiffness as the sway bar alone provides in many cars with other suspension configurations.

[r0tor]

Many cars with torsion beams have a (small) sway bar in addition, meaning that the torsion beam alone does not necessarily provide the same level of roll stiffness as the sway bar alone provides in many cars with other suspension configurations.

This one does not

[MX793]

No, I understand the dynamics of a torsion/twist beam suspension vs. multi-link.  There is certainly enough information on the web, as well as graphics to illustrate just about everything.  Torsion beam has the advantage of being more economical and it is well understood that most people would never detect a difference in their normal daily driving.  For that matter, there is likely very little difference in normal driving.

However, Mazda has always prided itself on it's 'handling' dynamics.  When designing the rear suspension for the Gen I Mazda 6 (Atenza), Mazda called on the expertise of a engineer largely responsible for the design of the Mondeo Gen II, which uses a related platform, in order to help design a unique rear suspension for the Mazda 6 (Atenza).  Slapping in a twist beam on the new Mazda 3 seems like a indication that Mazda has given up on their Zoom Zoom handling dynamics that Mazda prided itself on.

Certainly a cost cutting measure, and disappointing in that regard.  But I'd point out that the much-acclaimed, previous generation Civic Type R (2015-2018), the one everyone in America longed for, had a torsion beam rear suspension (previous generations had a "proper" IRS).  So did (does?) the Renaultsport Megane, regarded as one of if not the best handling car in the hot hatch segment.  So the torsion beam is cheaper and less sophisticated, but is certainly still very capable of delivering zoom-zoom performance.  If Mazda had abandoned zoom-zoom in the name of saving costs, they would have fitted a MacP strut arrangement.  Or a dead axle.

[MX793]

This one does not

Ok.  That still doesn't mean that the torsion bar design is inherently over-stiff in roll.

[Eye of the Tiger]

Many cars with torsion beams have a (small) sway bar in addition, meaning that the torsion beam alone does not necessarily provide the same level of roll stiffness as the sway bar alone provides in many cars with other suspension configurations.

Torsion beams, as the name might imply, are specifically designed to deflect torsionally, but remain rigid in every other direction. They are semi-independent, but basically equivalent to an independent suspension with a sway bar. The unsprung weight is probably the largest drawback of the torsion beam.

[Eye of the Tiger]

Also, the sky is blue.

[2o6]

Torsion beams are also very compact.



The problem I have with Mazda is they migrated towards a more basic setup, but somehow the car got even smaller inside!

[2o6]

It's just a weird move for a company thats prided itself on being "driver focused" and is making an upmarket push. Do torsion beams work? Of course. Do they work as well as a well designed true IRS? Hell no. Do details like that matter in a car billed as premium? I'd say yes.

Define "not as well" though. If it drives, handles, and rides good - who cares?


Suspension types have their advantages and disadvantages, and I think shitting on a torsion beam is dumb. I mean, cut out the "torsion" part of the torsion beam and you have a basic trailing arm setup which is "IRS". And no one shits on trailing arms like they do torsion beams.

[MrH]

Torsion beams are also very compact.



The problem I have with Mazda is they migrated towards a more basic setup, but somehow the car got even smaller inside!

+1 yep. That's the real problem.

[Laconian]

Yes, the interior space downgrade is bizarre. One of the nice aspects of my dad's 2018 3 is the huge amount of rear legroom (relative to the car size). Why'd they give it up? It's crazy!

[2o6]

Yes, the interior space downgrade is bizarre. One of the nice aspects of my dad's 2018 3 is the huge amount of rear legroom (relative to the car size). Why'd they give it up? It's crazy!

Huge? Uh....

[FoMoJo]

Torsion beams are also very compact.

The problem I have with Mazda is they migrated towards a more basic setup, but somehow the car got even smaller inside!

Is that due to the overall shrinkage of the car, or something else?

[giant_mtb]

Yes, the interior space downgrade is bizarre. One of the nice aspects of my dad's 2018 3 is the huge amount of rear legroom (relative to the car size). Why'd they give it up? It's crazy!

Pre-2019 rear legroom: 35.8"
2019 rear legroom: 35.1"

Less than 3/4" of change, butttttt okay.

Though "hip room" is down 3" between the two, among other changes.

[2o6]

Pre-2019 rear legroom: 35.8"
2019 rear legroom: 35.1"

Less than 3/4" of change, butttttt okay.

Though "hip room" is down 3" between the two, among other changes.

In person, it's worse.

Is that due to the overall shrinkage of the car, or something else?

Nope, Mazda is just not good at packaging.

[giant_mtb]

In person, it's worse.

I don't doubt it.  I've never put too much stock in numbers like that.  Lots of variability.  Like where the driver/passenger has their seat positioned, for instance.

[12,000 RPM]

When it comes to leg room, always look at the front and rear total.

[AutobahnSHO]

When it comes to leg room, always look at the front and rear total.

+1

[giant_mtb]

I must admit, I've never been in a position to bother looking at such numbers to begin with, so I know little about them or their true value.  I've only "shopped" for cars twice in my life, and both times I clearly didn't think about rear passengers, especially with the Taco.  In fact, the near-uselessness of rear-seat occupancy was a plus for me when I bought Taco..."ope, guess we gotta take somebody else's vehicle because rear seat of access cab Taco is not somewhere you wanna be for more than a short jaunt around town."

[12,000 RPM]

With rear facing child seats and a 5' 10" wife, it's life and death for me. Don't know if we're having a second one but I'm looking forward to the day I don't have to think about this shit.

[FoMoJo]

In person, it's worse.


Nope, Mazda is just not good at packaging.

Could it be that the trailing arms and the beam flapping around underneath may have needed a smidgen more room at the back than the multi-link setup?

[MX793]

Could it be that the trailing arms and the beam flapping around underneath may have needed a smidgen more room at the back than the multi-link setup?

Torsion beam is way more compact than any multilink.  Many multi-links, including the previous iterations of Mazda3, also have trailing arms.

This is the multi-link out of a 2nd generation (which, IIRC, is essentially the same as 1st and 3rd generations)


^^^Note the trailing arms

This is the torsion beam out of the gen 4.


The beam is set very close to the trailing arm pivot, so it wouldn't move much with suspension movement and would require very little sway space.  You wouldn't need to raise the floor like you would in, say, a live/dead axle (live axle Mustangs and a pretty prominent hump in the floorpan for axle clearance).  The trailing arms themselves are also quite a bit shorter than on the multi-link.

[FoMoJo]

That torsion beam setup seems quite compact.  My concern was that having the beam set far forward of the wheels may require the platform to be adjusted to make room underneath thus impacting the position of the rear seat.  That doesn't seem to be the case here, but the angle of the image does make it difficult to seen the actual length of the trailing arms.

[giant_mtb]

With rear facing child seats and a 5' 10" wife, it's life and death for me. Don't know if we're having a second one but I'm looking forward to the day I don't have to think about this shit.

...then why are you thinking of moving from an Edge to an Escape.

Get a Tahoe and call it a day.