17x8 Hypergrams with 205/40R17 RT660s?

[JasonB]

After reading about wheels and tires for about 3 days straight this is what I am thinking of.

I don't want to downsize the wheels because I have done that on other platforms and it feels less sharp in terms of turn it and feedback. That is specially why I bought this car. I don't need it to ride softer.

I just want do double check the width of the tires matches the wheels.

Tire rack says the tread width is 7.9" and according to this article, a tread width slightly less than the wheel width is good for performance.
“For ideal handling: when sizing a wheel for a given tire, I usually target the WHEEL to be the same width as the tire’s TREAD width, or 0.5” wider.”
-https://motoiq.com/how-to-properly-select-and-size-tires-for-performance/2/

These tires will be for daily driving in summer / warm weather and maybe a track day or two. I am prioritizing stiff sidewall, small sidewall, and bigger wheel size to preserve sharpness and feedback. Im not sure convinced I am going to reduce much unsprung weight from downsizing from here since these wheels are 16.33lbs. Maybe another 1.5lbs but thats diminishing returns coming from 22.5lbs stock. I would rather save 6.17lbs and keep the sharpness than save 7.5lbs on a 16 inch wheel.

Curious to hear the community's thoughts and if I might be missing something.

Thanks!

 

[Zala]

After reading about wheels and tires for about 3 days straight this is what I am thinking of.

I don't want to downsize the wheels because I have done that on other platforms and it feels less sharp in terms of turn it and feedback. That is specially why I bought this car. I don't need it to ride softer.

I just want do double check the width of the tires matches the wheels.

Tire rack says the tread width is 7.9" and according to this article, a tread width slightly less than the wheel width is good for performance.
“For ideal handling: when sizing a wheel for a given tire, I usually target the WHEEL to be the same width as the tire’s TREAD width, or 0.5” wider.”
-https://motoiq.com/how-to-properly-select-and-size-tires-for-performance/2/

These tires will be for daily driving in summer / warm weather and maybe a track day or two. I am prioritizing stiff sidewall, small sidewall, and bigger wheel size to preserve sharpness and feedback. Im not sure convinced I am going to reduce much unsprung weight from downsizing from here since these wheels are 16.33lbs. Maybe another 1.5lbs but thats diminishing returns coming from 22.5lbs stock. I would rather save 6.17lbs and keep the sharpness than save 7.5lbs on a 16 inch wheel.

Curious to hear the community's thoughts and if I might be missing something.

Thanks!

I just took delivery of a 17k mile loaded Fiesta ST myself. The OEM tires on OEM wheels are nearing 6 years too, but it looks like they were stored indoors since they seem to be holding air and gripping well enough in 50° weather.

I make it a practice to pick up a spare set of wheels and just get tires mounted separate of the car. This removes the potential factor for the shop to damage my car improperly lifting the car or over torquing the wheels on. With all that said, I just placed an order for 17x8 Hypergrams as well.

I expect your tread width quote of 7.9" is a typo (probably actually 6.9") for the 205. I too have been deliberating what size and I think I'll be going to a 215/40/17 Yokohama V701. Tread with at 7.5", definitely less wide from the wheel, so I expect it should be responsive since the overall wheel/tire package will be about 15 lbs less over stock. I do expect with the extra tread width all around that the steering might feel only a tad heavier, but I typically only notice that when turning the wheel while stationary.

 

[esp_martin]

to answer your question, the OEM Potenzas fit those wheels with some stretch. from what i've read, most tire shops will have no qualms with mounting that size tire on an 8in wide rim but i've never personally done that. i'm not sure if NT660s need to be stretched but others on this forum have said the Fiesta likes tires with a little stretch.

most who race the Fiesta that write about it here do so on 16in or 15in rims. a big reason is better tire selection but just as much of a reason is the decrease in unsprung weight/smaller moment arm (the weight of the rim is closer to the center, yay physics). another reason is the best dollar- to -perfomance flow formed wheels only come in 16in and 15in (konig dekagram, the td pro, etc). you've probably read all this already.

there is a handful of people who argue you should always fit AS BIG a forged/flow-formed rim as possible for the reasons you state and so you can fit as big a brake kit inside the wheel as you can. i don't know how/if negative camber closes this gap or if it improves handling the same regardless of sidewall height. the best argument though is Ford engineers designed the Fiesta ST with 17in wheels on 205/40R17 tires.

we can all make assumptions as to whether Ford engrs did that strictly b/c of suspension geometry, b/c someone in marketing was like "big wheels sell cars. i want big ol' wheels! not stupid tiny wheels" or some mix of the two. what i do know is that no Ford engr who worked on the design of the car is in this forum answering our questions. there is an infamous story of one FiST who changed the springs and 15in wheel/tire combo so drastically the car actually rolled at an autoX event. edit: that setup was pretty dumb but it's still a cautionary tale.

i'm a bit hypocritical because i have 215/45R17 for summers and will need to get aftermarket springs to bring the center of gravity back to/below OEM...which probably means i'll need to introduce a lot of negative camber to prevent rubbing.

everyone has their own approach to how they want their FiST shoes to fit. just keep it safe.

 

[M-Sport fan]

I expect your tread width quote of 7.9" is a typo (probably actually 6.9") for the 205.

The RT660s in 205/40-17 are 7.6" wide at the tread.

It is the 215/40-17s which are 7.9" in tread width.

 

[JasonB]

7.6 still seems doable for 17x8, right?
On the Falken website it says they can support wheels 7-8"

 

[M-Sport fan]

7.6 still seems doable for 17x8, right?
On the Falken website it says they can support wheels 7-8"

They will be perfectly fine on those wheels, with maybe even a hair better turn-in response than the 215s.

The only problem I can see is that they will leave the wheels a bit more susceptible to dings/damage from bad roads due to the more stretched, very very short side walls.
IF you can avoid the craters, etc., you will be fine.

 

[Zala]

The RT660s in 205/40-17 are 7.6" wide at the tread.

It is the 215/40-17s which are 7.9" in tread width.

Wow, that's very attractive for a 205. I figured only the Yoko A052s were on the wider side, but that's just me not remembering the Falkens. Now I just have to decide if I can make adequate use of a 200TW for summer street duty. I normally opt for a 300TW just because they tend to be more reasonable tread depth longevity wise for mixed weather (rain here) driving on my local hill country roads and tend to last me a strong 3-5 years (I don't put a ton of miles on tires per car since I try to drive all my 7-8 cars as frequently as possible). Due to the lower expected mileage I wonder if a 200TW tire will last me as long. I don't require the extra grip for my application as I can drive plenty fast on 300TW and some of my driving peers pump out the same level of driving on UHP all seasons (obviously higher skill sets than I).

I still run an extra set of A/S in the winter for the FWD cars to account for days were temps creep into the 30-40° range for 1-2 months. I too feel the OP will be just fine with the Falkens.

I'm staring a good bit at some Pirelli P Zero Neros on DTDirect right now due to active promotions: https://www.discounttiredirect.com/buy-tires/pirelli-p-zero-nero/p/101689

• Tire Rack's stats on these tires look odd: 6.9" tread width (this seems closer to spec), 23.7" diameter (closer to a 215), and max wheel width range of 7.5"
  • Promotional net price: ~$510
  • Cons: According to Tire Rack won't fit on the 17x8 wheel.
• DTDirect: 23.46" diameter, and max wheel width range of 8.5"
  • Promotional net price: ~$460

I think the best next step for me to just verify with DTDirect that the tire will fit a 17x8 and get a guarantee that they'll make right if they get it wrong (ie. giving me a 215/40 tire for the same promotional price).