2012 Ford Focus Titanium: Suspension Walkaround
A new 2012 Ford Focus sedan recently came our way, so we had no choice but to yank the wheels off and have a good look at the suspension. This one happens to be a Focus Titanium, the top trim level that Ford has added to the North American lineup.
Titanium Foci come with a sport-tuned suspension and 17-inch Continental all-season tires. But this example has the optional Titanium handling package, a $595 option that nets you stickier 18-inch asymmetrical summer tires and damper tuning that's dialed up another notch to get the most out of them.
Still, nearly everything we'll see is found on all Foci, be they hatchback or sedan, S, SE, SEL or Titanium. I'll point out any differences I know of as they come up.
MacPherson strut front suspension is pretty much the default in the compact segment these days, and so it is with the 2012 Ford Focus. The internal damping of the struts varies throughout the model range, but externally they look the same.
The coil spring sits high above the tire, surrounding the strut. A slender drop-link (yellow) descends from the upper reaches of the strut housing to the stabilizer bar. This direct-acting linkage produces a 1-to-1 motion ratio that gets the most of what the 23.5-mm stabilizer bar has to offer.
An aft placement of the steering rack (green) is expected in a transverse-engine machine such as this. The engine and transmission occupy the space in front so the steering rack must sit behind the front axle centerline.
Finally, the lower end of the suspension is held in place by an L-shaped lower control arm (orange) that's made of aluminum. Most Focuses will have an aluminum LCA like this one, but if I remember my notes correctly, entry-level S models and SE models without the SE sport package option will use one made of steel to help keep the price down.
Here's a look up at the same components from another angle.
Here's the suspension upri...WHAT THE HECK IS THAT CRUSTY CRUD?
My midwestern operatives tell me it's road salt. The 2012 Focus isn't for sale just yet, and we have this one thanks to a short-term loan from Ford. Mere weeks ago it was running around in Dearborn, slogging through the salt slush. The car was presented to us quite clean and spotless, but this particular area is hard to see and difficult to get at without removing the wheels.
Excuse me for a moment while I find my garden hose.
That's much better, though a toothbrush would have helped in the corners.
Anyway, the suspension upright (orange) isn't made of salt; it's an iron alloy piece. The upper end of the upright surrounds the base of the strut housing in such a way that a single bolt (white) can lock the two together. It's a cleaner and stronger design the the usual high-torque two-bolt sandwich connection we see on strut suspension most of the time.
But the other guys' two-bolt design does allow one to fake a camber adjustment by using smaller "crash bolts" to gain some slop in the connection that can be used to alter the alignment. The firm handshake of the Focus setup has no potential for such adjustment. Racers will have to settle for making performance adjustments the "right" way by installing aftermarket camber plates at the top instead.
Finally, our brake caliper (yellow) reveals itself to be a single-piston sliding caliper. The presence of the salt reminds us why the caliper sliders must be inspected to see if they need to be cleaned and lubricated when the brake pads are swapped out. No caliper I have worked on has ever been sticky or lacking in lubrication in this way, but then I don't drive on salted roads all winter, either. Frozen calipers certainly do happen, and the build-up of corrosive winter crud and grit is no help at all.
Before cleaning, the front side of the very same caliper looked great. For the record, those ventilated front rotors are 278 mm in diameter -- 10.9 inches for those of us unable to speak Canadian.
Here's another look at that aluminum L-shaped lower control arm. The ball joint is integral, so if it fails you'll be replacing the whole arm. Still, this sort of one piece design is lighter, and ball joints don't fail nearly as often today as they did on your grandad's car.
The green arrow is pointing at the stabilizer bar, which sits behind the steering rack, then loops over the top to meet the drop link.
The Ford Focus has electric power steer (EPS), but they call it EPAS because they throw the word "assisted" into their branded acronym. Ford prefers rack-mounted EPS as we see here (red) instead of the column-mounted design we saw in the walkaround of the 2011 Hyundai Sonata.
Why? Putting the assist downstream of the rack and pinion gear intersection assures that those gears will be lightly loaded. The upstream location of column EPS means all of the assist torque must be fed through those gears.
Also, rack-mount EPS retains a bit of natural mechanical steering feel because the u-joints in the steering shaft and the rack and pinion enmeshment are directly connected to the steering wheel. Column EPS utterly filters out this mechanical feel because all of those components exist "behind" the assist curtain, making it easier for column EPS to feel video-gamey.
Of course tire self-aligning torque that's created through caster, dynamic cornering loads and the tire's own internal construction is still in danger of being masked by rack EPS, but the Focus team has done a good job of carefully tuning the EPS assist levels to allow the driver to get a good sense of it all. On top of that Ford's EPS system is programmed to auto-correct for crosswinds and extreme road crown so you don't have to crank in any steering to drive straight in such conditions.
Here's a close-up of the upper attachment point (yellow) of the stabilizer bar drop link. The view is somewhat crowded by the presence of a mass damper (black) that's been installed to quell an unwanted resonant vibration in the system.
The rubber insulator between the spring and the strut is far from unique--all strut cars have one. What is interesting (to me anyway) is the obvious gap that provided an ample escape route for the slush and crud I rinsed out with my garden hose.
At the rear we find Ford's so-called Control-Blade multilink rear suspension, which is comprised of a trailing arm (black) and three lateral links.
A long lower link (white) carries the spring and the vertical suspension loads. This link shares lateral cornering loads with a second lower link (red), which is a much shorter "toe link" that pulls the front of the tire inwards as this link swings through a tighter arc. Up top is the camber link (yellow) which, as the name implies, holds the tire at the proper camber angle relative to the two lower links.
In concept this is very similar to our last 2008 Ford Focus long-term car, but the components are quite a bit beefier here and the track width of the suspension is greater by 2.6 inches in front and 2.3 inches here in the back.
This view from below shows how skinny the "blade" trailing arm really is. The trailing arm is tasked with fore-aft wheel location, so it doesn't need to be laterally stiff. In fact, a little sideways flexibility here is a good thing as the long primary lower link (white) and the shorter toe link (red) swing through vastly different arcs to create the desired amount of dynamic toe-in, sometimes referred to as roll understeer.
Meanwhile, our upper camber link (yellow) is characterized by an obvious curve that allows it to loop under the unibody and still maintain a favorable high-mount position at the pivot points.
Here's another view of the curved top link (yellow). Since it's all made from steel, the Control-Blade trailing arm (black) is welded directly to the rear suspension upright.
The shock absorber's lower mount ties directly to the rear suspension upright for a 1-to-1 motion ratio, a move that allows for precise and efficient damping.
That damping varies in about three steps throughout the Focus lineup, and our Titanium with the handling package has the most aggressive of them all. But you can't tell from the outside, where they all look like black-painted shocks.
Our rear spring is sandwiched between the stationary rear subframe and the moving lower link. It acts at a point 70-percent of the way out from the inner pivot, so the spring will compress about 0.7 inch for every full inch of wheel movement. The stabilizer bar's end link sits further inboard at a point that will move less than half an inch for every inch of wheel movement. Our eyeball estimate of the stab bar's motion ratio is about 0.45-to-1.
The only rear suspension adjustment is an eccentric cam on the inner pivot of the main lower link. Mostly, this will change toe-in as this link grows longer or shorter.
Meanwhile, the rear suspension bump stop is a hard rubber bullet (green) positioned out at the end where it can smack into the subframe and cushion the blow when things get really rough.
Same stuff, another angle. No arrows this time.
A stubby end link (yellow) connects the 19-mm rear stabilizer bar to the lower link. All Foci have the same 19-mm bar.
In Titanium trim, the Focus uses a single-piston sliding rear calipers and 10.6-inch (271-mm) solid rotors. The same is true of the Focus SEL and any Focus SE that's equipped with the sport package. Rear drum brakes appear on the Focus S and on SE models that lack the sport package.
Several wheel and tire packages exist on the 2012 Focus line, including 15-, 16-, 17- and 18-inch wheels, which are fabricated from steel, painted aluminum alloy or polished aluminum alloy.
A standard Focus Titanium wears the 17-by-7-inch wheels shod with 215/50R17 Continental all-season tires, but ours has the Titanium Handling Package, so it comes with these 18-by-8-inch alloys. Looks like the offset is 55 mm.
The real payoff with the Titanium Handling Package, a good deal at $595, are these Michelin Pilot Sport 3 summer tires with asymmetrical tread. The 17-inch all season's work impressively, but this 235/40R18 rubber grips better to the tune of nearly 2 seconds a lap on an autocross course we tried. The ride isn't quite as polished, however, and they're not the tire of choice in places where it snows or gets cold.
They'll cost more to replace, too. The 17-inch Continental's cost $146 apiece on Tire Rack. No prices yet appear for the Michelin PS3 tires, put Pilot Sport PS2 rubber in the same size costs $286 per tire.