Fiesta ST Owners: Anyone drop to 16 inch wheels?

My 2015 Fiesta ST has now reached the ripe old age of 102k miles.  It's due for new tires again, and the stock size Bridgestone RE50a's are leaving a little to be desired.  I live in New England, home to car swallowing potholes, which has done a great job of beating my OE wheels up pretty badly.  The 205-40-17s don't have a lot of sidewall, so I am considering going -1 on the wheel size, which should get me into a 205-45-16.  

Has anyone done this? The Fiesta forums and Reddit have tons of pictures of people who have, but no one really has answered the question of how much of a performance deficit there is, if there is one at all. Are there any downsides I am not thinking of? This is a daily driver and it only gets pushed on side roads.  No track days, no autocross, no 150 MPH highway pulls.

Tire buying always gives me analysis paralysis as it is, so the adding in new decisions is not helping any.

And because threads are useless without pics (fisheye lens, don't panic):

I did that with my MINI Cooper for potholes and ride quality reasons here in Michigan.  I went from 17" run-flats to 16" conventional tires. Short of doing a track day I don't notice any performance deficit. Modern cars are so competent that the performance deficit is at a point well beyond where you would normally be driving on public roads anyway. A quality set of 16" tires and wheels will work fine on an ST I would think.

I dropped from 17" to 16" rims with my Mazdaspeed Miata and noticed the performance deficit that the 17" rims had.  Reducing weight made a much bigger difference than the loss of sidewall stiffness.  One concern with 16s is fewer choices in tires, so know what tire you want before buying rims.

Yeah there's no problems with it. Most people autocrossing them are running 16s as well. Mine has had 16s (or smaller) for all but the first ~10k of its now almost 90k miles.

Would 15s fit over the brakes?

At least some do. I had a set of first gen focus 15s as winter wheels for a couple of years. That's getting into a ridiculous amount of sidewall though. It's entertaining but in a very different way.

My FiST came with 16s, but I didn't notice a difference compared to other FiSTs I drove with 17" wheels. This obviously isn't as good of a comparison as if I'd lived with the car in both configurations. I wouldn't hesitate to do it for a daily driver.

GRM recently posted an older article where they compared the performance of tires with smaller vs. larger wheels. The best lap difference was small, while the average was substantial.

My winter wheels are 15". Very different type of tire obviously, but I would hesitate to go that small. The FiST's party trick is turn in and it lost a lot of it. Again, it might be fine with a proper summer tire.

I run 15" winter tires, can't really say there is any improvement in the ride.

dps214 said:

At least some do. I had a set of first gen focus 15s as winter wheels for a couple of years. That's getting into a ridiculous amount of sidewall though. It's entertaining but in a very different way.

205/50-15 is not ridiculous in the least.

It's slightly shorter than ideal, but it's also really REALLY available because it's the +1 size for Miatas, as well as the +1 or +2 for lots of other Fiesta sized cars.

It's still not enough sidewall to prevent septadecagonal wheels after a while, of course, but way better than a 205/45.

It's almost an inch shorter than stock on a car that already has almost comically short gearing. If you want more sidewall 195/50 or 205/50 16s are totally fine and are what I usually run. (Currently debating between the two sizes for the next set) I even had 205/55s for a little while but the fender liners did not appreciate them and they looked a bit silly.

^ Stock 205/40/17 is 23.5" tall.

205/45/16 is 23.3" tall.

205/50/15 is 23.1" tall.

205/50/16 is 24.1" tall.

For the OP - The sidewall on 205/40/17 is 3.2" vs 205/45/16 is 3.6". It's a pretty small difference

iceracer said:

I run 15" winter tires, can't really say there is any improvement in the ride.

I too run 15's for my snow tires, but I feel 2 things in the butt dyno: bumps don't want to shake my teeth out, and the steelies with Blizzaks are noticebly lighter than stock.

Snrub said:

^ Stock 205/40/17 is 23.5" tall.

205/45/16 is 23.3" tall.

205/50/15 is 23.1" tall.

205/50/16 is 24.1" tall.

 

For the OP - The sidewall on 205/40/17 is 3.2" vs 205/45/16 is 3.6". It's a pretty small difference

More reading has netted that a lot of people go to 205/50/16, and love the turn in response... Analysis paralysis ...killin me...

I will say, brake dust will be a nightmare, but this looks pretty nice:

If you want better turn in response, set the front toe a little bit more aggressive. Going from whatever stock is to ever so slightly less than zero toe is probably the most noticeable individual change I've made to mine. (and while you're at it, loosen up the strut tops and slam them all the way in for the extra couple tenths of a degree of camber)

In reply to jpaturzo :

Wax the wheels before you start using them, and use a toilet brush and water to clean them.  It's amazing.

In reply to Pete. (l33t FS) :

If I do go down the white wheel path, I am going to give this a try:
https://www.hotrod.com/articles/does-it-really-work-armor-all-brake-dust-repellent-tested/

It's worth a shot at least.

jpaturzo said:

In reply to Pete. (l33t FS) :

If I do go down the white wheel path, I am going to give this a try:
https://www.hotrod.com/articles/does-it-really-work-armor-all-brake-dust-repellent-tested/

It's worth a shot at least.

Interesting!

I also wouldn't worry about short gearing.  For 100k miles, I mostly highway-drove a (stock, large engined) car where 75mph in 5th gear was 4000rpm, and I survived to tell the tale.  What was funny was that the engine was pretty much dead over 5000, so even a full-tilt 0-60 run involved three upshifts, since 3rd gear ran out of juice about 55-58mph.  (It's going to be FUN with boost)

jpaturzo said:

In reply to Pete. (l33t FS) :

If I do go down the white wheel path, I am going to give this a try:
https://www.hotrod.com/articles/does-it-really-work-armor-all-brake-dust-repellent-tested/

It's worth a shot at least.

I've been using that stuff for a while now. Not sure it quite lives up to expectations on actually keeping the wheels clean, but it definitely makes them much easier to clean. My wheels still build up dust quicker than I would like, but I can't remember the last time they took more than a quick wipe with a rag to clean off. One interesting effect of it is that you'll know right away if you miss any spots when applying the stuff, because ALL the brake dust will accumulate in that one spot.

I run 185/60 x 15 winter tires on '97 Contour rims, the ones with caps. They probably are not very light. 

They ar slightly taller but not enough to bother.

At 35 psi, I guess there is slightly less crash on harsh bumps.

At normal highway speeds they handle OK.   Hey, they are WINTER tires.

 Won't be long before I can put the summers on, then the fun begins.

Currently running 16x8 Konig Dekagrams on 215/45R16 Azeni 615k+ for track days and autocross on my 2015 Fiesta ST. Also have 15x8 Dekagrams on order and will run 225/45R15's shortly.

The 16x8's are a glorious setup if you run 215's. IF you go for 205's they will wear the outside shoulders if you dont add a ton of camber(i was at -1.7ish and it would scrub the shoulders badly).

Here is a picture.

Pete. (l33t FS) said:

Would 15s fit over the brakes?

Here is mine with 15x7's and 205/50R15 RS-RR's. They fit over the brakes perfectly fine.

Nothing to add on the Fiesta side of this.  But I talked a friend into downsizing his 20' Golf R from 19" to 17" OZ Rally wheels, he loves the ride improvement and its more pothole friendly. 

My autocross setup is 16" wheels, with a 205/50 or 215/45 series tire it is great. 

 

I went for more width and tried a 225/50-16 but that was way too tall.  Killed transitional response. 

I also tried a 40-series and it was so short that 1st gear was useless and I had to go to third even on short courses. 

You can go to a 15" wheel, that's what the spare is IIRC. That's a lot of sidewall and many people do that, especially in pothole prone areas.  

As for tires, I was actually impressed with the OEMs but they didn't last long. I'm on Kumhos now and so far so good. 

In reply to pinchvalve (Forum Supporter) :

The Bridgestone's that came on the car were great...for like 12k miles.  The next 20k miles aren't that fun.

I am rapidly homing in on the Sparco's with 205/50/16s.....

This may be a terrible idea, or it might be great.  All I know is that my new hobby will be cleaning wheels.

205-50-16 Firestones.