[wam22]

Has anyone gone with larger tires on the 20" Carrera S rims? I am thinking of swapping to the Michelin PS4S from the P Zeros and I have been struggling with grip after getting an APR tune. My previous BMW M4 had 305s (IIRC 285 was standard) on the back and traction was fantastic.

235/35 and 275/35
235/35 and 285/35
245/35 and 285/35

Curious if anyone has any experience with increasing the tire size from the stock 235s and 265s using the combos above.

 

[Hal H]

I have a CGTS 4.0 - which comes with the Carrera Sport 20" wheels 8.5" front / 10.5" rear widths

OEM tires are 235/35 front - 265/35 rear and when the time comes around (summer spec Pirellis are OEM) to replace the tires, I'll go with the GT4 OEM sizes of 245/35 front - 295/30 rear.

They fall right in the middle of the measured rim width specs and will fit the wheels just fine
(the GT4 wheels have a few mm offset differences and the rear wheels are .5" wider (11")

 

[marco_polo]

Assuming my car comes with 10.5”J rear wheels (nobody seems to know the spec of Style Edition rear wheels) I’ll be fitting 295/30/20 asap, mainly for rim protection.

 

[Scrounger]

I emailed Porsche GB about this a couple of weeks ago as I'd like a bit more rim protection on the 10.5J width that the 265s lack. Their response was to speak to my local OPC who would be able to give me a definitive answer. I haven't spoken to my OPC yet though.

 

[marco_polo]

This is where my money will hopefully go

Michelin Tyres / Car / Michelin Pilot Sport 4S PS4S - 295/30 R20 (101Y) XL (N0) TL Fuel Eff.: D Wet Grip: B NoiseClass: B Noise: 73dB Car Tyres - MPV Tyres - People Carrier Tyres - 20" R20" - 295/30/20, 295/30R20 <span class="col00f">OE Porsche</span>

Buy online cheap Michelin Tyres / Car / Michelin Pilot Sport 4S PS4S - 295/30 R20 (101Y) XL (N0) TL Fuel Eff.: D Wet Grip: B NoiseClass: B Noise: 73dB

www.camskill.co.uk

I’ll probably stick with the standard 235 fronts. It’s a lightweight car, I don’t want to encourage the nose to aquaplane.

 

[Treemagnet]

I have a CGTS 4.0 - which comes with the Carrera Sport 20" wheels 8.5" front / 10.5" rear widths

OEM tires are 235/35 front - 265/35 rear and when the time comes around (summer spec Pirellis are OEM) to replace the tires, I'll go with the GT4 OEM sizes of 245/35 front - 295/30 rear.

They fall right in the middle of the measured rim width specs and will fit the wheels just fine
(the GT4 wheels have a few mm offset differences and the rear wheels are .5" wider (11")

Would like to do the same with our BGTS Turbo wheels, but worry about fit...especially the rear. Will you be doing this with a completely stock front and rear GTS 4.0 suspension? If so, can't wait to learn the results. If not, what suspension mods have you made...still want to know your results.

 

[wam22]

I have a CGTS 4.0 - which comes with the Carrera Sport 20" wheels 8.5" front / 10.5" rear widths

This is where my money will hopefully go

Michelin Tyres / Car / Michelin Pilot Sport 4S PS4S - 295/30 R20 (101Y) XL (N0) TL Fuel Eff.: D Wet Grip: B NoiseClass: B Noise: 73dB Car Tyres - MPV Tyres - People Carrier Tyres - 20" R20" - 295/30/20, 295/30R20 <span class="col00f">OE Porsche</span>

Buy online cheap Michelin Tyres / Car / Michelin Pilot Sport 4S PS4S - 295/30 R20 (101Y) XL (N0) TL Fuel Eff.: D Wet Grip: B NoiseClass: B Noise: 73dB

www.camskill.co.uk

I should specify it is a Cayman S with Carrera S wheels, so the wheel width is .5" smaller:

• Front: 8J x 20 ET57 wheels with 235/35 R20 tires
• Rear: 10J x 20 ET45 wheels with 265/35 R20 tires

285 will be pushing the max size with 275 sitting comfortably for a 10" rim.

 

[Hal H]

Would like to do the same with our BGTS Turbo wheels, but worry about fit...especially the rear. Will you be doing this with a completely stock front and rear GTS 4.0 suspension? If so, can't wait to learn the results. If not, what suspension mods have you made...still want to know your results.

No suspension mods - at the end are pictures I shot (with my 20 Carrera Sports) - plenty of room around the suspension in the rear.

With 295s on my wheels, they'll probably be similar - here's the offsets on the wheels GTS = ET47 vs GT4 = ET50 (remember than the GTS rear wheel is 10.5" and GT4 / Spyder wheel is 11" the offset difference is very minor being 3mm)

the optional 20" 911 Turbo wheels are the same spec as my GTS 20" Carrera Sport wheels - so a 295/30 will fit

Heres images of the OEM rear 265/35 tire - there's plenty of room around the tire/wheel and suspension

 

[Treemagnet]

No suspension mods - at the end are pictures I shot (with my 20 Carrera Sports) - plenty of room around the suspension in the rear.

With 295s on my wheels, they'll probably be similar - here's the offsets on the wheels GTS = ET47 vs GT4 = ET50 (remember than the GTS rear wheel is 10.5" and GT4 / Spyder wheel is 11" the offset difference is very minor being 3mm)

the optional 20" 911 Turbo wheels are the same spec as my GTS 20" Carrera Sport wheels - so a 295/30 will fit

View attachment 54103

Heres images of the OEM rear 265/35 tire - there's plenty of room around the tire/wheel and suspension
View attachment 54104
View attachment 54105
View attachment 54106

This is awesome news! Thanks Hal for all your efforts to get those pics....looking forward to upping the ante with a larger footprint.

The info below came from using Tire Size Calculator. The only real negative is the sidewall is reduced by 0.2" or 5.4%.

265/35R20	295/30R20	Difference
Diameter : 27.3"	Diameter : 27.0"	-1.1%
Width : 10.4"	Width : 11.6"	11.5%
Wheel : 20" x 9-10.5"	Wheel : 20" x 10-11"	1.1%
Sidewall : 3.7"	Sidewall : 3.5"	-5.4%
Circum. : 85.7"	Circum. : 84.7"	-1.1%
Revs/Mile : 739	Revs/Mile : 748	9
Spedo @ 60 MPH = 60	Spedo @ 60 MPH = 58.5	-1.0%
Spedo @ 60 MPH = 90	Spedo @ 60 MPH = 87.9	-1.0%

 

[Bourneo549]

I’ve done the gt4/spyder sizes. 245/295 and can confirm I am much happier now with this setup.

8.5/10.5 wheels

 

[Treemagnet]

I’ve done the gt4/spyder sizes. 245/295 and can confirm I am much happier now with this setup.

8.5/10.5 wheels

...on a stock 718 GTS suspension?

 

[Scrounger]

It's well documented on Rennlist that the 245/295 option is aesthetically better and offers more rim protection however the 245 does give slightly more understeer. The stance does change slightly by raising the nose and lowering the rear but only by mms.

For thise interested, heres my old 718 running Carrera Classics which are an 8J & 10J with the standard 235/265 setup

 

[Bourneo549]

...on a stock 718 GTS suspension?

On S-pasm.

-1.6 camber front, -2 rear.

Looking for lower arms next but it is better on track with this setup than stock. N rated PS4S also in these sizes. Not the regular ones

 

[Bob V]

Spedo @ 60 MPH = 90

what does Spedo @ 60 MPH = 90 mean? the tire size site does not explain it.

 

[Wiscombe64]

what does Spedo @ 60 MPH = 90 mean? the tire size site does not explain it.

I suspect it means 60 was a typo? Guess it should be 90.

 

[Hal H]

I’ve done the gt4/spyder sizes. 245/295 and can confirm I am much happier now with this setup.

8.5/10.5 wheels

you'll have to post close-up pictures

its looks so silly with the wheel face protruding further than the sidewall and the tire looks stretched
with the 235 / 265 setup on the GTS

 

[Bourneo549]

you'll have to post close-up pictures

its looks so silly with the wheel face protruding further than the sidewall and the tire looks stretched
with the 235 / 265 setup on the GTS

just looks normal imo now!

 

[Scrounger]

Did you notify your insurance about the tyre size change? Did it cause you any issues?

 

[Treemagnet]

On S-pasm.

-1.6 camber front, -2 rear.

Looking for lower arms next but it is better on track with this setup than stock. N rated PS4S also in these sizes. Not the regular ones

That's all the negative camber we were able to dial into our GTS, so it's great to learn you made it work without any interference or rubbing.

I suspect it means 60 was a typo? Guess it should be 90.

Thanks....edited to 90 MPH.

 

[Bourneo549]

Did you notify your insurance about the tyre size change? Did it cause you any issues?

Yes. I am in the uk. A-plan Thatcham is the broker. The underwriter they used doesn’t mind mods. You just need to notify them of the changes.