Track wheels

[franky]

Hi guys,

I am thinking of putting a set of wheels to my 718 GTS 4.0 for track use.

The current setting is 
Front: 235/35 20 8.5 +57
Rear: 265/35 20 10.5+47

If I want to change it to 18 inches wheels will it be too small to fit?

Whats the max spacer width you will put on your rear wheel?

Also anyone have experience to change the width of the tyres and find that mess up the handling? 

Thanks

[Peter John]

Great move- go for some koya’s- give them a call. Stick with same width without spacers. They’ll know the offset. 

[Ian718]

Hey Franky,

Great idea with the track focussed 18” wheels. Here is a good starting point/summary page: https://apexwheels.com/fitment-guides/porsche/cayman/porsche-718-cayman-wheel-and-tire-fitment-guide#hardcore-track

My own personal experience (and that of my friend with a 718 GTS 2.5L): Yes, they will fit the 718 GTS 4.0 as the front rotors are 350mm (I have 350mm gyrodisc). 18s don’t work on the GT4 unless you change the brakes (OEM is 380mm steel or 410mm ceramic).

I use 18” forged Koyas for the track. 18x9” ET46 front  18x10.5” ET 36 rear

18” wheels unlock much much faster tyres than regular Cup2s. My personal preference is Yokohama A050s (medium) 265/35/18 front  295/35/18 rear

Those width tyres won’t fit with stock suspension. I have 2.5deg neg camber at the front to make the 265s fit (front camber plates + Ohlins R&T coilovers). They recommend 3 degrees, but my car is a dual purpose daily driver/track car. I don’t think it’s possible to fit any wider in the front.

The rear is 2.0deg neg camber due to the lowering from the Ohlins and 295s are getting pretty close to the limit of what can fit. (But they don’t make any wider A050s)

Wider sticker tyre handling is night and day improvement over OEM sized Cup 2s. Lap times have improved so much that in a base Boxster with no power mods I now sit right in the middle of the GT4 pack at the PCNSW sprints.

Are you planning to join PCNSW? It would be great to see you at the sprints

[franky]

Hey Ian, 

Thanks for all the information! I am newbie to the track and it help a lot.

I join PCNSW last year and def interesting to get to know more about the sprints. I might tag along with you next time you there!

I am looking at a set of used wheels with the following settings

Front:18 x 9 / Tyre 265/35 / Off Set 50
Rear:18 x 10 / Tyre 295/35 / Off Set 35

Do you think I will have to set 2.5 degree neg camber for the front to fit with standard suspensions?

Cheers,

[Ian718]

Hey Franky,

It would be great to see/meet you at the PCNSW sprints! The next one is at Pheasant Wood (Marulan) track on Sat 3.2.24. There are some relatively minor barriers to entry to the sprints, you need a fire extinguisher (+ bracket to affix it to the car), 2 tow hooks for front and rear (car comes with one, but you need to buy another), and you need an appropriate helmet. Contacting a place like PR Tech in Brookvale can easily get all of this sorted.

You won't be able to fit a 265 width front tyre on the 718 platform with OEM suspension. The OEM suspension will not adjust to 2.5 deg neg camber in the front.

However just taking it back one step, when you say you are a newbie to the track... exactly how many track days have you done, and what are your current times on any of the NSW tracks (and in what car)? I reckon if you are a true newbie to the track, you shouldn't worry about maximising the width on your track tyres just yet. I would just go with your current suspension and tyres and learn the correct racing line, braking points, turn in points, apexes, etc. Then after you get the racing line, you work on your balancing your throttle/brake inputs to your steering inputs to constantly be on the limits of your tyres traction.

Even better if you can get an instructor in the car to help you. PR Tech are running a driver training day at Pheasant Wood the day before the supersprint (Fri 2.2.24) where you can do this. In my opinion you don't need an instructor in the car all the time. But you need to know what you are aiming to execute, and then you can just practise practise practise execution to your heart's content.

Once you get skilled enough at track driving, that you feel the OEM suspension and tyres are holding you back, then go for min/maxxed track wheels/tyres with the appropriate suspension changes to allow them.