While Jay was out riding shotgun in a plain white 2012 Hyundai Veloster, I managed to get my mitts on a Starsky and Hutch themed example in our new lab for a look-see at the suspension.
Once the shock of that stripe wears off the next thing that jumps out is the 2012 Veloster is clearly smaller than an Elantra. This impression largely stems from the V's length, which is a full foot shorter -- 12.2 inches if you're keeping score at home.
After that, however, the differences are less dramatic. Its 104.3-inch wheelbase is 2 inches shorter than that of the Elantra. The Veloster is simultaneously 1.4 inches lower and 0.6 inches wider, and its base curb weight is lighter by 77 pounds.
These dimensions are close enough that the suspension layout can be similar. Suspension tuning is another matter, though, as the Veloster's springs, dampers, tires and other tunable elements have been dialed up to make it decidedly sportier.
Up front the Veloster rides on your basic coil-over MacPherson strut suspension -- or is it?
The Veloster's lower control arm (yellow) is of the one-piece stamped steel variety. There's also a direct acting stabilizer bar that uses a long slender link (white) to connect the stab bar directly to the strut housing. The Veloster uses a 24mm bar, one larger than the Elantra's 23mm piece.
But it all looks so clean and tidy. Something seems to be missing.
Here's another look at the lower control arm (yellow), and from this angle we can clearly see the rear-acting steering (green) that's common to front driven machines like this one.
But I still feel like I'm overlooking something. What can it be?
A-ha! It turns out that our Veloster is the first car we've ever come across in the walkaround series that puts the brake caliper and the steering arm on the same side of the axle centerline. It does not conform to the convention that would normally place the brake caliper in front of the axle in a rear-steer front-drive car such as this.
Hyundai was able to do this for a handlful of reasons. First, the Veloster uses a single-piston (black) sliding brake caliper, a design that works on a light car like this but only has bulk in the middle where that piston is.
Second, the steering arm attaches to the knuckle from below, putting the bulky ball joint itself lower down.
But the third factor is what really makes this possible: instead of the usual 3 o'clock position used by rear-mounted brakes, this Veloster's pinchers sit at 1:30 or thereabouts, leaving just enough room for the steering arm to sneak underneath.
Why do it this way? I have no official answer, but a couple of possibilities come to mind. This layout puts both elements to the rear, a move that reduces nose weight and improves weight distribution.
"Yes, but that has to be small potatoes," you're thinking. I hear you, but every little bit helps on a nose heavy front-drive machine. Still, this is probably not the driving factor.
How about this one: Putting the brake caliper in its normal place opposite the steering may give the relatively heavy caliper a large moment to use against the steering, perhaps making brake vibrations more persistent and harder to damp out. The inertia effect might be significantly lessened by putting them closer together. Here the separation distance is just 1 or 2 inches instead of the usual 9 or 10 inches.
I haven't convinced myself this is actually the case, but it sort of sounds good on the surface.
As you might expect, this arrangement has a drawback or two. The steering tie-rod is closer to a heat source and will therefore run hotter, but this isn't likely to be an issue because the tie-rod is underslung and because high temp grease formulations are easy to come by.
The main drawback for enthusiasts may be this: there seems to be no room for something like a Brembo 4-piston fixed caliper aftermarket brake upgrade for the Veloster. There simply doesn't seem to be enough real estate with this knuckle design and brake placement.
All of this applies to the Elantra, too, because its front suspension shares these brake and steering design elements. Look at the pictures in our recent 3-car compact comparison and you'll see the same 1:30 brake caliper placement we're looking at here.
Other than the 1:30 aft placement, the Veloster's single piston sliding caliper and ventilated front rotors are fairly straightforward.
Like the Elantra, the Veloster uses a twist beam rear axle -- but the two cars do not share the same design.
Like all such twist beam axles, the beam itself behaves like a big stabilizer bar with wheels on the end. But the sportier Veloster needed more rear roll stiffness than the Elantra.
In order to accomplish this, the Veloster needed a different twist beam design. In an Elantra, the central span of the twist beam, the part that crosses the car, is a hydroformed piece with a given roll stiffness that can't be easily boosted.
In order to jack up the roll stiffness in the Veloster a simpler folded cross beam (white) was used in order to provide sufficient space in the void for a sizable welded-in supplemental stabilizer bar (yellow). Welded in bars also allow a suspension tuning engineer to swap out axles with different bar diameters. The one they settled on here is 23 mm in diameter.
If mounted square, the relatively soft twist beam pivot bushing you want to combat ride impact harshness would deflect far too much under cornering loads and allow lateral deflection oversteer to rear its ugly head. Mounting the bushing at an angle helps manage this conflict. This approach was rare in early days of twist beam axles but is widely accepted now.
The Veloster's rear suspension reveals another unusual detail. In most twist beam setups the coil spring sits up front with the damper behind, but here the two are swapped. The Veloster's damper (yellow) is also reclined toward an attachment point that's more or less in line with the axis of the coil spring.
This seems to be an attempt to keep the forward area clear for the fuel filler pipe (white) which itself may be a little lower than usual because of the need to provide decent rear seat passenger space.
Here's another view from the inside. Incidentally that shock absorber is a monotube damper, a more expensive choice that can make more damping force and still run cool. It's a good sign.
The Veloster's rear disc brakes consist of single-piston sliding calipers and solid rotors.
The standard Veloster tire package consists of P215/45R17 rubber mounted on 17 x 7-inch rims, but 215/40R18 tires mounted on 18 x 7.5-inch rims are available.
At first glance it appears that Hyundai used a fairly tried-and-true suspension approach for the Veloster, an approach that makes sense for a car of this size and price point. But they've also gone off-script a little and applied some interesting tweaks.
We're intching to drive this beastie on the road and take it to our test track to see how it all works out. But we can't go there just yet; we have to wait until we get the green light. Stay tuned.
v8vader says:
10:19 PM, 05/26/11
torsion beam rear axles make me sad =(
especially in a cool little car like this
andrewhon says:
10:27 PM, 05/26/11
Wheel weight would be interesting.
bc1960 says:
10:54 PM, 05/26/11
Didn't the Sorento also have the front brakes and steering link mounted rearward--I think most FWD Hyundais and Kias do, including some older ones. I've noticed this and wondered how they worked it.
iancar says:
12:49 AM, 05/27/11
These look amazingly clean and tidy designs. I wish the same can be said about the Flex's suspensions and brakes layout.
oldchap says:
03:47 AM, 05/27/11
Thanks as always Dan! Can you comment on the McPherson knuckle? How can we tell the traditional style from the new designs supposed to limit torque steer?
vierwege says:
04:23 AM, 05/27/11
Thanks for the update! One thing that I would like find out is if the Veloster (and other FWD cars that you do walkarounds on in the future) has equal length half shafts from the transaxle or not. From picture #6 it looks like there is a mass damper near end of the half shaft so I am guessing that they are unequal. Disappointing for a FWD car that is slated to be sporty. Heck, even the current Honda Fit has equal length halfshafts. Though, interestingly enough, only on the automatic equipped models and not the manuals. Any ideas as to why that is?
I know this is just a press car but the third from last picture with the jack stand on the pinch weld made me wince. Here in the snow belt any abrasion from metal on metal contract quickly leads to rust.
juan_mx says:
06:27 AM, 05/27/11
Is the right side of the suspension the same as the left side? (you have to ask that for this car)
I wonder what is the white blob on the lower bolt of the rear shock.
Looks like a piece of chewed gum.
Thanks Dan for another interesting walkaround.
Sorry to insist, .....any chance to get the 2011 Jetta?
mini23 says:
07:13 AM, 05/27/11
The Volkswagen Corrado had a torsion beam axle. It was one of the best front wheel drive handling cars on the market when it came out. In fact I read from old reviews it pulled .86 G on the skid pad back in 1992. Torsion beams are less expensive then multilinks but that does not mean they are automatically bad. It's all in the engineering.
bankerdanny says:
08:09 AM, 05/27/11
Wouldn't a very long slender stabilizer link like that be subject to some flex that reduces the efficiency of the stabilizer bar?
baggs32 says:
09:32 AM, 05/27/11
Hyundai's exec said they benchmarked the CRX when developing this car. IIRC the CRX (back in the late 80s) had an advanced, for the time, double wishbone suspension in the rear. Only track time will tell if the Veloster is just as good, but I have my doubts.
acbayard says:
10:24 AM, 05/27/11
Oldchap: why are you constantly plugging the rev knuckle?
How to deal with torque steer? This car has only 140 hp and 120 lbft.
Torque steer? What? Equal length drive shafts will help more than any suspension.
bankerdanny says:
11:30 AM, 05/27/11
My 1991 SE-R only had 140hp AND it had equal length drive shafts AND limited slip, regardless of that it also had torque steer.
subytrojan says:
11:30 AM, 05/27/11
Dan da Man!!!
acbayard says:
01:43 PM, 05/27/11
bankerdanny: was it new?
bankerdanny says:
02:40 PM, 05/27/11
No, I bought it in 1997. But I also sold Nissans in 1991, so I have driven new ones.
It didn't have TS the way my V8 Taurus SHO did or my Jetta 1.8T does, but it was still there.
acbayard says:
02:46 PM, 05/27/11
I find it hard to imagine how torque steer can occur in a car that is properly adjusted, and enjoys equal drive shafts. It defies the definition of torque steer.
jawzx says:
06:28 PM, 05/27/11
@acbayard
My 1992 Alfa Romeo 164-s had both equal-length half-shafts and limited slip, but with with 200+ HP I can assure you that torque steer happens even when accomodations are made, and in a great handling, well set-up car. The revo-knuckle is a lovely aid, and every little bit helps. I hope someday to drive another front-drive car as good as that Alfa was... I doubt it'll be a Hyundai, but I could be wong... I quite like my 2011 Elantra Touring.
clerk1892 says:
05:32 AM, 05/28/11
Chick car.
kimbo305 says:
06:24 AM, 05/28/11
"The inertia effect might be significantly lessened by putting them closer together. Here the separation distance is just 1 or 2 inches instead of the usual 9 or 10 inches.
I haven't convinced myself this is actually the case, but it sort of sounds good on the surface."
It was pointed out to me that the least polar moment (wrt to the steering axis) is if the caliper were mounted up top or on the bottom. Up top would probably be better for avoiding clag/dirt from the road. I don't buy that mounting them opposite/same-side makes a big difference, since torque acting on the caliper comes from the knuckle, not the tie rod directly.
corduroy_gt says:
06:36 PM, 05/30/11
You have to first have torque to have torque steer.
actualsize says:
07:40 AM, 05/31/11
@bakerdanny: A long slender stabilizer bar link can indeed flex if it is too skinny. I have actually used the diameter of links like this as a tuning element, and to a certain extent you can feel the difference in initial roll speed at turn in.
But this only works if the slenderness ratio (eye-to-eye length divided by diameter) of the initial design is near the 30:1 range, the point at which engineering textbooks will tell you that flexing and the potential for column failure in compression are a risk. If a design comes in under the wire at 29:1 or thereabouts you can feel a change to 27:1, but at some point around 25:1 (hazy memory - don't hold me to it) everything is as firm as it's going to be and you're just needlessly adding weight after that.
I didn't measure it, but this one's slenderness ratio is comfortably on the safe side.
actualsize says:
07:46 AM, 05/31/11
@juan_mx: The "white blob" is the head of the shock bolt (the nut is on the other side.) Instead of a hex, which would have to be held with a wrench, this bolt's head is t-shaped such that it runs up against the axle housing and stops turning all by itself during assembly. No wrench is required on this side to torque it down.
actualsize says:
08:23 AM, 05/31/11
@vierwege: The mass damper can't be taken as an absolute sign of unequal-length driveshafts. I didn't check the other side and make a note of this, though, so instead I'm looking at a picture I didn't use in this walkaround. The photo does strongly suggest unequal driveshafts, but I'm not 100% certain.
But that's not a tragedy for the Veloster. A lot of car companies use equal-length driveshafts on their V6 models and unequal designs on the 4-cylinder versions because, as someone else pointed out, you have to have a certain amount of horsepower and torque to have torque steer. Also, 4-cylinder models are built to a lower price target and the unequal-length design is clearly less expensive.
Equal-length driveshafts in 4-cylinder applications are becoming more prevalent now that turbocharging is coming back into wider use. The Veloster hasn't got a turbo (so far, anyway) so an unequal-length design would not surprise me in this car.
The time to start worrying about torque steer is if and when Hyundai puts a stouter turbo mill in the thing. At that point they'd probably step up to an equal-length design to handle it properly.
occadriver says:
11:25 PM, 06/ 5/11
Interesting read about the suspension and brakes.
I rented a small Citroen. The steering rack was located at the top of the firewall, the rack end was attached to the upper portion of the strut. This arrangement saved a lot of space around the front knuckle and presumably reduced the amount of weight at the wheel. Wonder why we don't see that arrangement these days, especially with electronic power steering?
phonebook says:
11:59 AM, 06/ 7/11
It's a shame that the brake design will make upgrades difficult/unlikely... was really hoping to see the the aftermarket of the Veloster.
arfdog3 says:
05:17 PM, 12/ 1/11
A couple things:
"The inertia effect might be significantly lessened by putting them closer together. Here the separation distance is just 1 or 2 inches instead of the usual 9 or 10 inches."
It doesn't matter whether the caliper is mounted front or rear, the lever arm length from the steering axis is the same, therefore the rotational inertia will be the same. If it was mounted at the 12 o'clock position, that would reduce the inertia and the steering could conceivably feel lighter or more direct.
"One thing that I would like find out is if the Veloster (and other FWD cars that you do walkarounds on in the future) has equal length half shafts from the transaxle or not."
Actually, it doesn't matter if the half-shafts are equal length if the goal is to eliminate torque steer. They only have to be *equal torsional stiffness* to accomplish that. Therefore, you can have a short and long half shaft but still have no torque steer. By making the long half shaft adequately thicker, it will have a higher torsional stiffness and can be made equal to the shorter shaft.
Viola, no need for an intermediate shaft then.
Technically, the shafts need to be equal mass (and therefore inertia) too, to avoid differential rotational acceleration, but no car with an intermediate shaft will feature that.