• Sign Up! To view all forums and unlock additional cool features

    Welcome to the #1 Fiesta ST Forum and Fiesta ST community dedicated to Fiesta ST owners and enthusiasts. Register for an account, it's free and it's easy, so don't hesitate to join the Fiesta ST Forum today!


What's the biggest tire we can fit without issues?

Messages
37
Likes
12
Location
Tuckahoe
#1
So I'm coming to the end of my warranty and I'm looking at mild upgrades. Mountune MP215, Thermal exhaust, Quaif lsd. I like the stock suspensions ride/ height compromise so I'm not looking to change there as all the options I've seen lower the car. However I'd like a little more grip. Again, because it's my daily I want to keep the aspect ratio as close to stock as possible. What's been the widest tire, tire/wheel combo you folks have been able to get on without issues?
 


Messages
404
Likes
574
Location
Anchorage
#2
225/45R15 RT660s on 15x8" Team Dynamics 1.2s- these work for me, and I'm lowered, so you should be fine. Bilstein B6s will give you a more comfortable, more controlled ride without changing your ride height.
 


OP
Scootny
Messages
37
Likes
12
Location
Tuckahoe
Thread Starter #3
I'm curious, why the switch to a 15 inch rim? What do you think I can get away with on the stock 17 inch rim?
 


Messages
404
Likes
574
Location
Anchorage
#5
I'm curious, why the switch to a 15 inch rim? What do you think I can get away with on the stock 17 inch rim?
I think folks have had difficulty getting a 225 under there without going to a 15- I could be wrong.

Also, cheaper and lighter.

One issue I hadn't thought of for a stock height car would be how it looks, if that is a concern for you.
 


ronmcdon

Active member
Messages
560
Likes
677
Location
Beverly Hills
#6
currently on 205/50/16. Hoping to get 225/45/16 with fender rolling, or failing that throw on m2 fender flares (sitting in garage). Eventually will experiment with 17x9 +35 wheels (on order already and will arrive Jul-Aug) and try to go wide as possible, 235 or 245 fingers crossed.

oh and I think you can get very close to stock height with coilovers. Fortune Auto should be able to get you that but you would have to contact them and specify. I have 200 mm Swift springs used in conjunction with Meister R GT1 coilovers and drop might be somewhere around stock to 1/4 inch drop. With the stock coilover springs barely 1/2 inch when maxing ride height.

I go for stock height too as my goal is to fit in as much rubber as possible. It's my understanding height of the front fenders remains a clearance issue. If the tyre is too tall, may rub top of wheel well.

I will say the tall ride height at times is kinda scary with track events as at times I worry if Im going to roll the car. Have not experienced this with other cars Ive driven.
 


Last edited:
OP
Scootny
Messages
37
Likes
12
Location
Tuckahoe
Thread Starter #7
Much love and thanks to all of those who dropped their knowledge. Does anyone have experience with a 215/35 18? I'm am loathe to lose any sidewall but I have to wonder and ask. Thanks!
 


kevinatfms

Senior Member
Messages
873
Likes
923
Location
Germantown
#8
16x8 and a 215/45R16 is the closest to the stock tire height as you can get with the widest wheel offering. Its a 23.5-23.6" tire which is .1 larger than the OE 205/40R17.

Going down to a 15" wheel you can get a 225/45R15 under the car but its 0.5" shorter than stock. Sticking with a 17" wheel gets you a 215/40R17 which is a bit taller than stock at 23.8".

Going to an 18" just looks odd and weights on anything but the most expensive wheels is significantly more than the 15/16/17 inch offerings.
 


ronmcdon

Active member
Messages
560
Likes
677
Location
Beverly Hills
#9
what determines a tire being too high? guessing ride height and how soft springs are.

also not sure how high is too high
 


kevinatfms

Senior Member
Messages
873
Likes
923
Location
Germantown
#10
what determines a tire being too high? guessing ride height and how soft springs are.

also not sure how high is too high
Stock tire is 23.4" tall. Fenders have enough clearance at stock height for right at/under 23.8" tall tire. Lowering can bring up challenges with this size.

Too high is anything over 23.8" from what ive seen. Hence why people either go shorter at 23" or so(205/50R15, 225/45R15, 205/45R16) or slightly above at 23.6"(215/45R16). The tallest i think that we can run currently is 215/40R17 at 23.8" tall without rubbing(depending on wheel offset and lowering amount). 24"+ tall tires are just too tall/wide(most are 235+ in width) to fit under the stock fenders but some have made them fit with flares and some cutting. Some have tried the 225/45R16 size and either had zero issues or rubbed badly. So that is up for debate.

The widest tire that I know fits without rubbing, without flares or beating the interior of the wheel wells up is a 225/45R15 on a 15x8 +35mm.

I haven't seen anyone try a 245/40R15 yet but it could fit knowing its a 23" tall tire that can fit on an 8" wheel. Offset and camber would be key to ensuring it does not rub the strut housing, spring or fender liners.

Most track guys run 205/50R15, 225/45R15, 215/45R16, 205/40R17 or 215/40R17 as they are commonly available extreme performance tire sizes. Wheels are 15x7(common), 15x8(hard to get), 16x7(common), 16x7.5(a few choices), 16x8(Dekagrams), 17x7(good amount of choices), 17x7.5(a few choices) and 17x8(a few choices).

If i have something wrong someone will correct me but i think that encapsulates alot of it.
 


ronmcdon

Active member
Messages
560
Likes
677
Location
Beverly Hills
#11
thanks for detailed explanation!

only inquiring the limits, maybe obsessively at times, as trying to run wider rubber and wheels and seeing what I can get away with.

currently running 205/50/16 Z3 @ 24.2” as per tirerack. wheels 16x8 +35. Iirc, with different tires there are slight variances with height and width of tire.

this actually rubbed a little on my stock suspension, but only in sweepers with marked incline and decline on some streets. Otherwise was ok and rubbing not so severe. Maybe thats getting close to the limit, height wise of the tire is my guess.

Moving to coilovers with slightly stiffer 5/3k rates and 1/2 drop (now closer to 1/4 to stock height and 8/6k) did not get rubbing. also have -2 camber front, -0.8 rear.

clearance with the outer fender not as concerned about. fender rolling is pretty easy. had mine done this weekend. I think the inner clearance to the suspension and height maybe a bit trickier.

going to test out a set of 225/45/16 just ordered from tirerack and will report if that rubs. its under 24” but wider.

also my later objective is to fit as wide rubber as possible w 17x9 +35 wheels. Thankfully have some really old 245/40 z2 tires I never put on an another car. sadly not a lot of ppl have gone beyond 215/17 tires even with 17x9 wheels
 


M-Sport fan

9000 Post Club
Messages
14,101
Likes
6,755
Location
Princeton, N.J.
#12
Wheels are 15x7(common), 15x8(hard to get), 16x7(common), 16x7.5(a few choices), 16x8(Dekagrams), 17x7(good amount of choices), 17x7.5(a few choices) and 17x8(a few choices).

If I have said something wrong someone will correct me, but I think that encapsulates a lot of it.
NOTHING 'wrong', but just that Braid will make you any of the above wheels sizes, with the proper center bore, but, they will co$t you a good portion of what the best condition/lowest miles examples of these cars are even worth. [wink] [:(] LOL
 


ronmcdon

Active member
Messages
560
Likes
677
Location
Beverly Hills
#13
yeah I think the more affordable braid fullrace a’s are going to run close to $1,300 for a set of 4, plus around $200 shipping, which I believe includes 17x8 and 16x8 sizes.

gets lot more expensive when you’re shooting for more custom sizes like say 17x8.5 or wider
 


M-Sport fan

9000 Post Club
Messages
14,101
Likes
6,755
Location
Princeton, N.J.
#14
yeah I think the more affordable braid fullrace a’s are going to run close to $1,300 for a set of 4, plus around $200 shipping, which I believe includes 17x8 and 16x8 sizes.

gets lot more expensive when you’re shooting for more custom sizes like say 17x8.5 or wider
Custom (like any +1/2") sizes jump up exponentially in price, and they get ~$100.00 PER WHEEL EXTRA for any color except for 'rally white'. [crazyeye]
 


Messages
314
Likes
267
Location
Portland, OR, USA
#15
Another data point:
Stock tires are 23.5" tall
I am stock springs and run 215/40R17 so 23.8" tall
I was running 205/50R16 so 24.1" tall

Local guy here runs 245/45R16 (I assume on an 8" wheel) and he claims "barely any rub", this is a 24.7"

So a lot is possible, depending on what you do for suspension/fender rolling/wheel offset. Running a 9" wheel is going to push you outside the fender lip, meaning you need to go to flares (and cut fenders back), or sit high enough (with enough bump stop) to not hit the fenders on full compression.
 


ronmcdon

Active member
Messages
560
Likes
677
Location
Beverly Hills
#18
thats pretty far out if it's ty
Another data point:
Stock tires are 23.5" tall
I am stock springs and run 215/40R17 so 23.8" tall
I was running 205/50R16 so 24.1" tall

Local guy here runs 245/45R16 (I assume on an 8" wheel) and he claims "barely any rub", this is a 24.7"

So a lot is possible, depending on what you do for suspension/fender rolling/wheel offset. Running a 9" wheel is going to push you outside the fender lip, meaning you need to go to flares (and cut fenders back), or sit high enough (with enough bump stop) to not hit the fenders on full compression.
that's impressive the guy can run 245/45/16 no rub.

I think the tyre is toyo r888r's and yes indeed there's a 245/45/16 size. Tire rack state sect width being 9.6. Tread width 8.5. Overall Diameter 24.6. promising to know he doesn't rub anything at all.
hard to say what wheels those are. I think the brand is Motegi. Dont see that design wheel on their site. However they do have some 16x7 in 4x108 at +35. Would be unconventional setup to say the least with stock suspension, 16x7 wheels, 245 tires (would think it'd be too wide for wheels) and on 100tw track tyres no less haha. Crossing my fingers he really doesn't rub. Even better if he runs more aggressive camber than -2 fronts.

anyhow will do some experimenting on my end. Have spare tyres I have in my garage, confirmed are antique Dunlop Z1 star specs actually 255/40/17. Was hoping they were 245/40's but sadly not. Don't have stats on that, but newest Dunlop Z3 in same size is sect width 9.7. Tread width 9.0. Overall Diameter 25.1. The height will be most risky is my guess. Sect and tread width similar enough to the r888r's in 245/45/16 size that my guess is it's not something flares can't address. If this works, car would look great.

should find out if this fits, maybe closer to Aug when my wheels arrive from europe by container. I already have fenders pushed out inch or so according to reputable body shop. Also have m2 flares on hand in case needed. Will go buy a pair of skinnier 235/40 or 245/40 if the 255's don't fit.
 


Last edited:

felopr

Senior Member
Messages
815
Likes
370
Location
JD
#19
i have used for years 205/45/17 on the stock wheel and rota titans with stock springs and B6 and tires have never scrape anywhere on the plastics
that is 24.26"
some people here have tried 215/45/17 and some say that it touches at full lock with stock springs and stock shocks but some say it doesn't touch so.
215/45/17 is 24.62"
people have run here 225/40/17 and it works fine on stock wheels/stock height and it works fines also. maybe a slight touch on full lock? don't know
225/40/17 is 24.09"
In my opinion, the most you can get away is 24.40
 


Intuit

3000 Post Club
Messages
3,650
Likes
2,254
Location
South West Ohio
#20
I too have stock suspension and wheels with 215/45R17. (stock tire is 205/40R17)
Only time I've gotten rub is when bottoming out the suspension or when the dealership screwed-up the alignment after having screwed up the diagnosis. (must be part of their evil plan - screw up the car so you'll come back and buy another -- (plan failed 😆))
When bottoming or *very* nearly-bottoming out, the tire hits the spring plate for the strut assembly.

The car very much notices the additional tire weight. But it's also good to be able to get far more of that stock power down. Spinning is not going anywhere.
 




Top