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15x8" Wheels

8773 Views 19 Replies 10 Participants Last post by  Izzy
When I get my FiST I'll be looking for some smaller wheels for autocross use. Unfortunately a 205/40/17 tire doesn't leave much room for a wider tire size while retaining a similar overall diameter, so going to a smaller wheel will be needed.

Performance tire choices in 16" wheels are not as good as 15", however wider width 15" wheels are hard to find in 4x108 bolt patterns.

Anyone find some 15x8 wheels in 4x108 bolt pattern? I've got some leads but nothing yet.

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Take it you are not doing Stock or Street . Since I have not looked yet are there many 16 inch options in tires yet ?? the little bit I have looked for wheels are either rather spendy or very limited on style and weight savings but I have only looked at the big retailers so far.
16x8 wheels are easier to find, but for performance tires the common sizes are:
205/55/16 and
225/50/16 both are 1.4" larger on diameter.

Finding 205/40/17 high performance tires is just as hard. Best option is a 225/45/15 in which many companies make a high performance version.

I ran G-stock in my SVT Focus for a year before I moved to STs and ran there since. I don't think I could run Stock or the new street class (depending on the final rules) as I drive my cars all over and do everything with them. I don't want to be restricted on mods to stay in a class.

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Neat it will be interesting to see where the FiST ends up and how bad the SCCA messes up the lower end (pref wise) cars with this new classing . either way it will be what it is and the is always STF and beyond :)
Yeah, I just run in my region and have only been to one divisional, never to nationals. So I'm not hardcore, but I am competitive locally and want to run in a class that is fun and not frustrating.

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I hear ya there !!
16" options suck, 15" leaves no room for big brakes but there is the Dunlop Direzza Z2 in 215-40r17.

I doubt any new 16" options will materialize but enough cars use 17s that if the ST is really popular, we might get a BFG Rival that fits.

I think the best bet for "state of the art" compounds in street tires is 17".

In a lot of race classes, +/-1" is allowed before you get bumped a class so a -2" might make an ST uncompetitive.
Big brakes will jump you into back higher class a lot easier than smaller wheels. You also don't need big brakes in autocross like you might on a track.

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Figuring out the best way to fit wide tires under the FiST's fenders will be very important for autocross success... 255 tires are really necessary for doing well in STX, where the FiST might end up. Think there is any chance of getting 17" 255's under there?
Has anybody crunched the numbers to see where the FiST tops out at redline in second gear? That might sway my decision to go taller or not. As long as there's nothing too funny in the ECU reasonable torque should be available.

Michelin Pilot Super Sports in 215/45R17 are down to $146 each on Tire Rack. I currently have a set on the Focus on 17x8 SuperTurismos.
I think red line in second is just under 60 which is why the 0-60 times are a lot slower than a Focus ST.

The gearing seems funky to me, a taller final drive (or bigger wheels) would probably help low speed acceleration (especially with a tuned car making more power) and make 6'th a better overdrive but 5'th is spaced so close that 2,3,4 and 5 should be re-spaced.

I bet its a matter of how many teeth they can fit on each gear but that spacing just confuses me.
They may have tuned the ratios for mpg.
I think red line in second is just under 60 which is why the 0-60 times are a lot slower than a Focus ST.

The gearing seems funky to me, a taller final drive (or bigger wheels) would probably help low speed acceleration (especially with a tuned car making more power) and make 6'th a better overdrive but 5'th is spaced so close that 2,3,4 and 5 should be re-spaced.

I bet its a matter of how many teeth they can fit on each gear but that spacing just confuses me.
Would launching in 2nd be a no go because of turbo lag?
16" options suck, 15" leaves no room for big brakes but there is the Dunlop Direzza Z2 in 215-40r17.

I doubt any new 16" options will materialize but enough cars use 17s that if the ST is really popular, we might get a BFG Rival that fits.

I think the best bet for "state of the art" compounds in street tires is 17".

In a lot of race classes, +/-1" is allowed before you get bumped a class so a -2" might make an ST uncompetitive.
If you guys will go on BF Goodrich's web site they have a survey to participate in for what you would like to see. If everyone did this asking for proper 16" and 17" BFG Rivals to fit the Fiesta ST they would listen. They listened to the autocross community when they developed the Rival and R1R... Don't delay. we need them by March!!!
Per Redeker top speed is 58 mph in 2nd....
Would launching in 2nd be a no go because of turbo lag?
I think the Viper has a 60 mph first gear but it also has 8l of V-10 to pull it.

Lag isn't the problem, its torque.

Lag is like a Ford Probe 2.2 turbo, nothing-nothing-nothing-BAM!

The Fiesta ST has essentially no lag, if the rpm is close to 2,000 just give it throttle and it pulls pretty good, even in sixth.

With slightly taller tires like a 215/40r17, that will act like a slightly taller gear and I think Cobb has already figured out how to raise the redline so a 60mph second gear is very doable, we just don't have quite enough torque to get fast acceleration times while skipping first.

Maybe a heavily tuned ST with ~300 ft-lbs at the wheels might pull second from a stop but then you have essentially a 4-speed transmission because first isn't needed and sixth is almost the same ratio as fifth.
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I will have an option. Stay tuned.
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Will that option be a 16x8 in a flush offset please! I know that will let me run a 225 comfortably front & back, but once I put a bigger turbo I'll try a 245 in front only.
Will that option be a 16x8 in a flush offset please! I know that will let me run a 225 comfortably front & back, but once I put a bigger turbo I'll try a 245 in front only.
Team Dynamics does not have a 16x8 :/ .
Then they need to...a 4x100 conversion is ever more near...:headbang:
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