Stock Front and Rear Suspension Changes Between Early/Late Production

[RKTFiST]

I couldn't find a dedicated thread for this, so I wanted to post the information and the sources for future reference. My apologies if this already exists somewhere and my search-fu was weak. There is spec'd change in rear beam thickness, despite the part numbers I found via Tasca to be the same for the rear beam from 2014-2017. Cutoff dates below are culled from the date of supplement revision, not actual production job information. Having a more reliable set of cut off dates would be great for future junkyard hunters.

2014-2016 (through 9/16 production) Fiesta ST Suspension specs:

Suspension Specifications
Item Description
MacPherson strut with L-arm front
suspension and revised knuckle
Front suspension
Rear suspension Twist beam (7.5 mm thick)
Front spring rate 30 N/mm (171 lb/in)

At a Glance
Item Description
Rear spring rate 25 N/mm (143 lb/in)
Front stabilizer bar 19 mm (0.75 in) diameter
Rear stabilizer bar Not applicable

Source:
http://www.fordservicecontent.com/Ford_Content/catalog/owner_guides/14fstst1e.pdf - 2014 Fiesta ST Supplement
http://www.fordservicecontent.com/F...-ST-Supplement-version-2_st_EN-US_10_2014.pdf - 2015 Fiesta ST Supplement
http://www.fordservicecontent.com/F...-ST-Supplement-version-1_st_EN-US_05_2015.pdf - 2016 Fiesta ST Supplement

2017 (2/16/16 Production+)-2018 Fiesta ST suspension specs:

Suspension Specifications
Item Description
MacPherson strut with L-arm front suspension and revised
knuckle
Front suspension
Rear suspension Twist beam 0.3 in (8.5 mm) thick
Front spring rate 154 lb/in (27N/mm)
Rear spring rate 131 lb/in (23N/mm)
Front stabilizer bar 0.83 in (21 mm)
Rear stabilizer bar Not applicable

http://www.fordservicecontent.com/F...pplement-version-1_su_EN-US-EN-CA_10_2016.pdf - 2017 Fiesta ST supplement
http://www.fordservicecontent.com/F...&div=f&vFilteringEnabled=False&userMarket=USA - 2018 Fiesta ST supplement

If anyone could provide more clarity on build cutoffs for US spec production changing from the old rates to new, that would be awesome. Most people wouldn't notice a difference between relatively minute changes like these, but I haven't checked yet on what the old vs new damper part numbers (and maybe bump stops) are. Someone looking to bolt ST parts onto a non-ST may find this useful.

Edit: thanks for the updates in the thread. I've updated this post accordingly.

 

[CB022481]

02/16/2016 seems to be the magic cutoff date.

 

[Meowoosh]

For H Street purposes, could one with a 2017 bolt on springs from the earlier models or would that not be allowed? Sad to see such a shift in spring rates..

 

[Truth in Ruin]

I can tell a big difference between the two.

 

[KKaWing]

I can tell a big difference between the two.

Curious which one you prefer?

 

[KKaWing]

I can tell a big difference between the two.

Curious which one you prefer?

 

[felopr]

so, later models have bigger front sway bar and bigger rear twist beam but softer spring rate? (only 20lbs apart tho)
later models should be "more rigid" but slightly.
We still dont know 1 variable, damper rating. Are they the same?

 

[Truth in Ruin]

Curious which one you prefer?

The 2016, by far.

 

[Truth in Ruin]

Curious which one you prefer?

Double post. The turn-in and reduced body roll on the 16 is way better.

 

[BRGT350]

There are multiple reports that the 2014 bushings are stiffer than the ones used on 2015+. The 2014 cars used the bushings from Europe, but those were deemed too harsh for the US market. I have driven both a 2014 and 2015 and couldn't tell the difference.

 

[Capri to ST]

This thread touched on suspension and other changes-

http://www.fiestastforum.com/forum/...hanges-Improvements-to-FiST-Through-the-Years

 

[TrickSTer]

The 2016, by far.

With the cutoff date being 02/16/2016, the "2016" you drove, could be either spec.
You don't happen to know if your "2016" was pre or post change date do you?

 

[Truth in Ruin]

With the cutoff date being 02/16/2016, the "2016" you drove, could be either spec.
You don't happen to know if your "2016" was pre or post change date do you?

I’d have to look, but I’m willing to bet the springs are stiffer in my 16. It’s a night and day difference.

 

[danbfree]

The '14-'16 are stiffer out of the box with thinner bars, and even though the '17+ goes from 19mm to 21mm for the FSB and a mm thicker on the rear beam to help against bump steer it does have a bit of extra body roll from the softer shocks but is still pretty harsh as a daily... for best of both worlds at reasonable refinement, you can do the Eibach springs which lower an inch, provide a less harsh but still nice and firm ride with progressive springs along with their matching beefy front (25mm over 22 stock) and rear sway bar (22mm, no rear stock) kit, Whoosh has the best price anywhere on the Eibach kit. For all out performance, the Swift Spec-R are the best springs, I believe they have the right balance being linear in the front and slightly progressive in the rear.

 

[RKTFiST]

Now that I've owned an early 2014 and have over 10k miles on my 2018, the 2014 was the sharper car, but the 2016 is a better balanced daily driver. The 2014 transitions with more immediacy on track, and from the factory, the alignment was spot on. My 2018 arrived with a maximum allowable toe-in and still feels more sluggish on turn in despite having less body roll. In the city or on any road with less than perfect pavement, the 2018 has a less jarring ride due to what feels like less rebound to my un-calibrated butt. I somewhat miss how frenetic the ride was in the 2014.

 

[danbfree]

Now that I've owned an early 2014 and have over 10k miles on my 2018, the 2014 was the sharper car, but the 2016 is a better balanced daily driver. The 2014 transitions with more immediacy on track, and from the factory, the alignment was spot on. My 2018 arrived with a maximum allowable toe-in and still feels more sluggish on turn in despite having less body roll. In the city or on any road with less than perfect pavement, the 2018 has a less jarring ride due to what feels like less rebound to my un-calibrated butt. I somewhat miss how frenetic the ride was in the 2014.

Exactly, with softer shocks, the '17+ does have a touch more body roll and a little less sharpness, even with a fatter stock front sway bar than previous years but is more tolerable as a daily... but also keep in mind that going with an even fatter sway bar will reduce body roll further and provide more sharpness to offset the softer shocks.

 

[Ford ST]

From 2/16/16 have the suspension update.

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[haste]

Yeah, my '17(built 11/17) feels like a Cadillac compared to my '15(built 8/14).

 

[danbfree]

From 2/16/16 have the suspension update.

Fronts were updated starting 2/16/16 and rear update started 6/14/16, for MY '17... So late '16's will have the front changed but not rear, kinda weird, they must have realized they needed to match up the rear to the front...

2016 Model Year
FRONT SUSPENSION
-4/1/2015 and 2/15/2016= original spec
-Updated on vehicle Build Date starting: 2/16/2016
REAR SUSPENSION
-Vehicle Build Date between: 2/16/2016 and 6/13/2016= original spec
-Updated on vehicle Build Date starting: 6/14/2016

This is condensed from the thread HERE

The front includes jump from 19mm to 21mm FSB as well, otherwise the main change in part# is 10% softer rate shocks/struts. and rear includes thicker rear beam.

Edit: As @Ford ST mentions below, all replacement part sites now show the rear updated as of 2/16/16 so maybe they really did front and rear at the same time, which makes more sense.

 

[Ford ST]

That's not how the OEM replacement parts are sold. You will see from the picture below about the rear axle beam.


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