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.
manuelc says:
04:22 PM, 02/23/11
Phenomenal work, Dan!
bradjames75 says:
04:25 PM, 02/23/11
That car, is beautiful.
2b2 says:
08:05 PM, 02/23/11
Great article, Dan! THAT was In-Depth :D
jeremiahhutch says:
08:54 PM, 02/23/11
This is a perfect example of how good an Inside Line review can be
juanvera says:
09:08 PM, 02/23/11
Indeed, great article! Thanks!
sohcammer says:
10:07 PM, 02/23/11
Ford gets a bad rap for their suspension, in reality Fords display excellent Ride Quality and the Quietest Cabin Around.
kyolml says:
10:15 PM, 02/23/11
How is trailing link feels? Does it feel like it will cause the back feel more forward and backward like the old trailing arms?
throwback says:
07:05 AM, 02/24/11
Nice job Dan. Yes, you do have to remove the wheels if you really want to get at all the road salt. I do this at the end of Winter. If there is a warm day (50+) I will also do this during the Winter. You would be amazed how much salt builds up.
northsparrow says:
07:13 AM, 02/24/11
What verisimilitude! What realism! The contrast between the California sunshine veneer and the Michigan grime beneath was so moving. How could a suspension "walkaround" encapsulate the entire breadth of a nation? And the piece de resistance? It had to be the price break down of future replacement for 17' and 18' tires .
As for the suspension itself, it serves as a declaration of independence compared to those lame torsion
beams in Cruzes and Corollas.
whitey9 says:
08:25 AM, 02/24/11
Thanks so much for the "insight". I am certain we all would enjoy more of this, but it takes someone who isn't afraid to get their hands dirty to "jack 'em up". Thanks again!
carguy622 says:
08:44 AM, 02/24/11
These are great, thanks. I would love to get my hands on an SE hatch with the sport package and a stick.
actualsize says:
09:36 AM, 02/24/11
@whitey9: If you want more, I've done about 45 of these. Go to the right side navigation and look for a link to some of them under "More Categories." The rest reside in the Long-Term blog, where a similar Suspension Walkaround link appears in roughly the same place on the page. I try to add 2 per month.
hopster says:
10:22 AM, 02/24/11
"Racers will have to settle for making performance adjustments the "right" way by installing aftermarket camber plates at the top instead."
Dan, can you explain that a bit more...don't camber plates also alter your kingpin angle while the crash bolts would only affect camber?
cz_75 says:
11:04 AM, 02/24/11
Actually, single piston calipers fare pretty well w/ road salt. What doesn't are the four-piston fixed calipers that Toyota uses on their light trucks. I hope you took the Focus out for a bottom-blast carwash.
cz_75 says:
11:20 AM, 02/24/11
With summer tires, one wonders how they drove this thing enough to get it corroded with salt, since the tires/wheels are part of the factory package.
I'm not liking the need for camber plates, as that means the cost to gain camber adjustment, which is necessary on the street, not just track, if you want to achieve better handling, is going to be significant. I'd assume $250/side for a camber plate, more if they adjust caster.
I also don't like the non-replaceable ball joint, as that means you have no recourse to adjust geometry when lowering the car, at least not until someone comes out with an entire (and doubtless expensive) lower control arm with replaceable ball joint that allow use of longer ball joints. Meanwhile, the kids that slam these will be a danger on the roads (besides their usually poor driving skills) with the tricky handling issues.
csubowtie says:
11:54 AM, 02/24/11
Can you explain the roll-understeer thing? Looking at that picture, it seems like as the suspension droops, the shorter front link will pull the front of the towards the center of the car, and as it compresses it would push the front of the tire away from the car. Now in a car rolling as it goes around a corner, the inside would droop, and the outside would compress, causing the rear of the car to "steer" in a manner that would cause it to turn tighter, i.e. overtseer. Is there something I am missing?
santiagofdz says:
12:31 PM, 02/24/11
How wrong am I to say that save for different states of tune, this and the Mazda/Mazdaspeed3 are identical from this point?
http://blogs.insideline.com/roadtests/2009/11/2010-mazdaspeed3-suspension-walkaround.html
mckman says:
01:15 PM, 02/24/11
Thanks Dan! The suspension "walkaround" is always a good read.
lanceboyle says:
02:45 PM, 02/24/11
Great work! Minor technical point: all the refences to ratios in these walk-arounds look to be at the lower ball joint. Since the mid-point of the tire is outboard of that (55 mm inside of the hub face in this case), the effective ratios will be somewhat lower.
Anyone that wants to learn about roll-induced oversteer should drive an old Bugeye Sprite with the trailing quarter-eliptic springs that steer the rear wheels out of phase from the fronts as the car leans.
pc123456 says:
04:03 PM, 02/24/11
Nice write up.
What's with Ford and mass dampers? Whenever I see those, I think something wasn't engineered right, so they have to fudge it.
Also, in salty climes, that skinny control blade could rust out. Yikes.
06scooby says:
07:30 AM, 02/25/11
@cz_75: I was wondering that same thing... how were they driving that thing around with summer tires in detroit to gather all that road grime... I almost wonder if Ford swapped the wheels and tires before they sent it down south. I've driven cars with summer tires in the snow before... they are absolutely useless!
bodyblue says:
08:22 AM, 02/25/11
"Anyone that wants to learn about roll-induced oversteer should drive an old Bugeye Sprite with the trailing quarter-eliptic springs that steer the rear wheels out of phase from the fronts as the car leans."
EEEK I STILL have part of a Sprite seat up my kazoo from riding in one when going way too fast! GULP no kidding! Turn, lean, SNAP and there you are! BACKWARDS
6sptl says:
10:21 AM, 02/25/11
Another humdrum cheap suspension, however is nice to see that good rubber is filtering down to cheap transport. BTW tthe PS3 is not a replacement for the PS2 its a cheaper alternative for vehicles with smaller tire widths. I dont expect them to cost anywhere close to the PS2.
actualsize says:
01:08 PM, 02/25/11
@06scooby: You are correct, sir. They simply must have had other rubber on the thing in Detroit. There isn't enough grip to even drive the thing up the ramp onto the trailer.
You've seen this, right? We went out and measured exactly how bad summer tires are in snow, among other things.
http://www.insideline.com/features/tire-test-all-season-vs-snow-vs-summer.html
actualsize says:
01:26 PM, 02/25/11
@santiagofdz: kinda-sorta. The US and European first-gen Focus used the CW170 platform. The second-gen Euro Focus moved to the C-1 platform, shared with the Mazda3 and a handful of Volvos including the S40 and C70. Meanwhile, the US Focus stayed with the CW170 and we all got bent out of shape in the US and fumed "no fair!"
Now, this 3rd gen Focus has moved onto a platform shared with Europe and the rest of the Ford family. The global C-car platform is very similar to the C1 that the Mazda3 uses. I can't go as far as saying parts are interchangeable and it's all down to tuning, but I would not be surprised if that were at least partly true.
actualsize says:
01:34 PM, 02/25/11
@csubowtie: On the front end, roll toe-in leads does lead to more steering than you want, so you get roll oversteer up there. Front suspensions are therefore built to toe out with roll.
But the opposite is true on the rear axle. Rear roll-induced toe-in creates understeer. Don't see it yet? Think of a forklift, which steers from the rear. Toe out a rear tire on the loaded side and you steer out, like the forklift. In a corner, that would be oversteer as the rear tries to pass the front.
The missing element is a word you said yourself: droop. We're looking at the suspension jacked-up, in full droop. On the ground, these link will be level. From there, as the body rolls, the shorter one in front will therefore shorten to a greater degree than the longer one in the back, pulling the front of the tire in for a wee bit of roll-induced toe-in.
actualsize says:
02:25 PM, 02/25/11
@lanceboyle: The tire moves up in lock-step with the ball joint because the BJ is one with the knuckle, which is one with the wheel bearing and hub. The scrub radius doesn't much matter if the center of the contact patch is moving with the ball joint at 1:1. We're talking motion ratios, not leverage.
A bigger factor that does affect motion ratio is any lean angle of a spring, strut or shock. Art the end of the day, though, we're not designing suspensions here, we're just looking at them and having fun geeking out.
mentally says:
04:04 PM, 02/25/11
When are you showing the suspension of the new 5 series?
jrhoglund1 says:
05:44 PM, 02/25/11
THERE IS NO REASON FOR A NEW CAR TO SHOW SIGNS OF RUST ON ANY SURFACE, HIDDEN OR NOT WITH ALL THE COATINGS AVAILABLE THERE IS JUST NO REASON FOR IT ...AT ANY PRICE
cz_75 says:
09:00 PM, 02/25/11
"When are you showing the suspension of the new 5 series?"
They did the 7-series already - same thing only shorter.
kosmo69 says:
05:05 PM, 02/26/11
wait a min. the focus has a indy rear suspension but the more $$$ mustang does not? !!!
exinobel102 says:
09:38 AM, 02/28/11
This is the same suspension setup that is on the current and previous gen Mazda3. This setup handles great, but I wonder if Ford addressed the negative camber issue on the rear wheels. The negative camber makes the car's rear handle more aggressively, but also causes way more premature tire wear.
santiagofdz says:
12:40 PM, 02/28/11
Thanks for the answer Dan!
Keep up the good work.
power6 says:
08:44 PM, 03/ 2/11
Dan,
Why is a camber plate the "right" way to adjust camber? When you adjust it up at the top like that, you are altering the SAI, usually for the worse to get more negative camber.
Modifying camber at the clevis bolts lets you alter it without
I wouldn't expect one with your automotive engineer background to make such a statement. There are no models that I know of now or ever with adjustable SAI from the factory as a means of adjusting camber. But there are probably millions (practically every Subaru ever made for example) with adjustable clevis bolts. And millions more with camber "crash bolts"(every Toyota strut car ever made) specified as a replacement for adjusting camber.
Even from a racer's point of view, they may love their camber plates for ease of alignment and tire clearance, but their alignment sheet probably don't have their "included angle" on it either.
As I understand it, if free from the limitations of a strut suspension, engineers choose much milder SAI.
stretchsje says:
05:41 AM, 03/ 8/11
I just wanted to reiterate what power6 said: not only are camber plates generally considered the wrong way to adjust camber due to the SAI change, but Ford created its "RevoKnuckle" suspension just to move SAI in the other direction. Ford's RevoKnuckle seems cheap/easy to implement, so I wonder why they don't use it more often.
I agree with what others have said in that it looks like the Mazda3 suspension, in use since 2004. It's impossible to tell from the photos if any mounting points have changed that would give it higher/lower roll centers, more/less anti dive/squat, etc.
bc1960 says:
08:50 PM, 03/ 8/11
@kosmo69, the Focus is a FWD car, so IRS is fairly trivial to implement, even though some manufacturers choose to go the cheaper route and put money elsewhere; the Focus is going to cost more, close to comparably equipped, than many competitors. IRS on the drive wheels, even when they don't also steer, is a bit more complex, plus the Mustang's live axle is intentionally part of its retro image and charm. If the Challenger and Camaro were smaller and lighter then Ford might have a problem, but currently they don't seem to.
rexster says:
08:26 AM, 03/11/11
First of all, this walkthrough is great! Does anyone know what the bolt pattern is? The current Focus is 4x something, but this is clearly 5x something. If anyone knows that would be cool to know. I'm hoping it's 5x100 but I'm guessing it's not.
Second thing, I tried posting to this site using Firefox 3.16.15 and it doesn't work. After signing in the comment box never renders. That needs to be fixed...
rexster says:
08:59 AM, 03/11/11
I think I answer my own question. The Fusion is 5x113, so I'm betting that's what this is...
hopster says:
03:39 PM, 03/11/11
The bolt pattern is 5x108, the same as the C1 Focus & Volvo.
The wheel choice isn't as good as if they used the Mazda3 pattern of 5x114.3. But this is an improvement over the C170 Focus pattern of 4x108. Ferrari uses 5x108 also, but the offset wouldn't work. ;)
sconger says:
06:01 PM, 04/19/11
I have a 2008 Ford Focus SES and have had to put rear camber arms and front camber plates to try to get it to stop cupping the outside edges of the tires. I had hoped Ford would make this one adjustable, but it seems it is the same. The Bilstein website says they have struts and shocks for my car but it is instead for the European Focus which shares the chassis with the Volvo S40 and Mazda 3.
norm_peterson says:
09:22 AM, 05/ 6/11
"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."
I know I'm a bit late . . . but this bit of over-engineering will likely make for poorer drivers even as the car gets smarter. One should know when conditions tend to cause the car to drift away from the intended heading, as it's a pretty good hint that slowing down might just be a good thing to do.
power and stretch - "crash bolts" with their reduced shank and non-uniform shape are poor choices for high torque applications such as strut to knuckle attachment, and are particularly non-applicable for hard driving. If you can't clamp the stack of strut tabs and knuckle tightly enough, the knuckle itself can fail. If you overtorque the crash bolts to help keep that from happening (as in beyond their spec, which may only be half of the OE bolt torque spec), you can very easily yield them, making them worthless for anything that's any more critical than desktop ornamentation.
It's not the concept that's bad. Just the usual execution
Norm