Tyre sizes for FI

[Daninplymouth 61]

Hi, I just wondered what size tyres people are running with turbos fitted?

my car is a daily but is going on a few track days this year. Getting the TD kit fitted in a couple of weeks.

at the moment I’m running 225/40/18 on an 8” wheel, will this be enough tyre for the increase in power?

I’m not sure about fitting 235/40 as I feel the tyres will be getting to big overall 245/35 I would be ok with but would this work on an 8j wheel?

any input appreciated 

 

[VAD17 479]

8" is probably the minimum you can get away with. 8.5" was suggested when I was getting my FI kit from TD couple years back (mind you I was planning also to track it occasionally).

I ended up with 9.5, but tbh think its a bit too wide (I am on 245/40 18).

Hope this helps

Sent from my SM-G973F using Tapatalk

[MartinT 514]

Turbo is not the only type of FI.  I'm running 8" wheels with 225/45 17 Michelin PS4 on my supercharged BRZ.  The balance between grip and agility is pretty much perfect.

[Kodename47 446]

I run 215 45 17 Primacys. Don't see any need to go wider.

[GravelRash 62]

Running 225/45/r17 PS4. Doesn’t seem to be too worried by the turbo.

[Lauren 2259]

I really don't understand why you'd feel a need to change the width. Get the turbo fitted, drive it, see what you think. 👍 

FWIW, I think it's a pity that so many feel a need to totally over-tyre their cars, add huge amounts of rotational mass and unsprung weight. All of these contribute to ruining how the car drives and more so how it handles. 

[Church 209]

It's just subconsciousness at work, with associating F1/lambo countach and alike supercars barrel wide tyres as something required to go fast, or as something that fitted to car will make it "fast"/"supercar-like cool". In most cases result is neither and even have several illeffects, but it "feels" that it's right thing to do by hunch. And that's what often guides purchase decisions.

[Daninplymouth 61]

This was part of the reason why I asked. Of course I will be seeing how my current tyres go but was just after others feed back who have already gone forced induction.
My previous car handled more power fine on these tyres but that could’ve been helped by having more weight above the driven wheels. 

[Church 209]

At 8" wheel going wider then 235 imho will compromise steering feel sharpness a bit due excessive sidewall flex resulting in less responsive steer-in. If one wants go for wider tires, worth upping also wheel width .. though that of course will up spendings/budget. Not sure i'd wish to go for wider then 9, as in some cases with some tires at some alignment setups 9.5 is on verge of rubbing.

Then again 245/35 is a bit closer to stock wheel-tire overall diameter thus will change gearing ratio less then 235/40. Wider tires in general might be more suspect of aquaplaning even at lesser speeds, and of less profile height may cost more, though later is more attributable how common some specific sizing in general is, as that often governs specific sizing cost more. You haven't specified what tire model you are running now, only their size, but imho tire compound matters by far more then width. If your current tires already are grippy, i'd first check if current tires might actually be sufficient. Also, winter is not completely ended, and if it's still happen to be cold & dump outside, it may reduce grip of most summer tires, so i wouldn't write off that lesser grip as "insufficient". IIRC TD stage1 turbo kit wasn't some overkill insane one, but of mild gains. If current tires are some chosen by cheaper price and maybe high threadwear, then already mentioned MPS4S (also GY Eagle F1 Supersport and Contis Sport Contact 6) might be nice upgrade in grip, even in same sizing.

[Rich196 103]

If you over tyre the car you will kill the fun!

I run a 235/35/18 MPSS. Cosworth Charged and the car remains playful. I would get the turbo on, get used to it and see how you get on. Id be looking at a decent quality 225/235 section tyre.

[mart86 9]

I'm running 245/40/17 PS4's on a 9" wheel. Running TD stage 1 turbo.  Went with a lightweight wheel to keep unsprung mass down and still shaved 1-2lbs off a corner.  I was going to change from the primacy's no matter what as they didn't give the levels of grip I wanted especially on wet roads even at low speeds.  It now sticks like sh!t on a dry road and will have to push it past 9/10 to break traction.  It will still get tail happy on wet roads when pushing it but it's very predictable.  I think that's more down to the PS4's compound than the size.  You won't have any problem on an 8" wheel or 225 tyre.  Like others have suggested I'd stick with what you have and see if you're happy with it.  I changed mine at the same time as I was still running stock wheels and tyres.