265/285 width tires on stock PP wheels?

[tlr3715]

Anyone try to fit 265/285 width tires on stock GT performance pack wheels? (Comes with 255F/275R width) if so, what did it look like and how did the car handle?

When it’s time to replace tires thinking of moving from the Pirelli P Zero 255/275 to Michelin Pilot Sport 4S 265/285. Wanted to see if anyone tried it and if it does crazy stuff to the stability control system.

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[wesg79]

id imagine theyd be a bit bulge looking i did a 275 on the fron in s 20x10 and it looked great, a 265 on the narrow wheels i think would look odd

 

[AZ_Ryan]

What's your goal of doing this? The added width to the street surface will be minimal, and your tires will have some bulge.

 

[tlr3715]

Just looking for a little extra grip without having to pay for a new set of wheels. If cost were no option I’d probably get 305 width tires for the rear. I think that tire width would match the power and gearing well.

 

[AZ_Ryan]

Just looking for a little extra grip without having to pay for a new set of wheels. If cost were no option I’d probably get 305 width tires for the rear. I think that tire width would match the power and gearing well.

You're only gaining. 4" in width assuming you keep the profile size of 40. You will never feel that on the road. Not to mention bulging sidewalls may flex more in corners. If you want more grip, get wider wheels.

 

[Sofa King]

I prefer the wheels are wider than the tires... in fact, Ford does too... they use the same 255 F and 275 R on the DH with wider wheels than the GT.

 

[jml]

I have the same question, so I asked CGPT. Here’s the answer:

“Your STOCK PP wheels + 265/285 =
near-ideal fit.

Front wheel: 19×9.0J

• Recommended tire widths: 245–265 mm (275 is the max you should go)
• A 265/40R19 fits perfectly.
  Not stretched, not bulged → just fully supported.

Rear wheel: 19×9.5J

• Recommended tire widths: 265–285 mm (295 is pushing it)
• A 285/40R19 fits perfectly.
  Again → not stretched, not bulged → ideal support.

So NO bulging at all.
These are factory-friendly fitments”

For what it’s worth…

 

[Junkyard Dog]

I prefer the wheels are wider than the tires... in fact, Ford does too... they use the same 255 F and 275 R on the DH with wider wheels than the GT.

It is not just a preference. I posted a YouTube video somewhere here where the proved it using different tires and wheels.

Wider tires on a narrow wheel (pinched) actually slow the car down on track.

Found it! See next post.

 

[Junkyard Dog]

9 tests in total, three different tire widths on three different wheel widths.

Adding tire width reduces lap times, up to a point. Increasing wheel width for the same tread width reduces lap times again.

Watch this and see what you think.



Which tire size was fastest?

What was more significant, tire width or wheel support (wheel width)?

They also test in the wet toward the end of the video.

 

[AZ_Ryan]

I have the same question, so I asked CGPT. Here’s the answer:

“Your STOCK PP wheels + 265/285 =
near-ideal fit.

Front wheel: 19×9.0J

• Recommended tire widths: 245–265 mm (275 is the max you should go)
• A 265/40R19 fits perfectly.
  Not stretched, not bulged → just fully supported.

Rear wheel: 19×9.5J

• Recommended tire widths: 265–285 mm (295 is pushing it)
• A 285/40R19 fits perfectly.
  Again → not stretched, not bulged → ideal support.

So NO bulging at all.
These are factory-friendly fitments”

For what it’s worth…

Definitely take chat GPTs word for it.

 

[jml]

You are probably right, Gemini 3 says the opposite

 

[MidwayJ]

What was more significant, tire width or wheel support (wheel width)?

The test showed either extreme (pinched or too stretched) was slower.

 

[GooberDH]

Anyone try to fit 265/285 width tires on stock GT performance pack wheels? (Comes with 255F/275R width) if so, what did it look like and how did the car handle?

When it’s time to replace tires thinking of moving from the Pirelli P Zero 255/275 to Michelin Pilot Sport 4S 265/285. Wanted to see if anyone tried it and if it does crazy stuff to the stability control system.

I would just keep it simple and stick with stock sizes, my S550 GTPP had the same tire sizes. No hard launches but with hard acceleration and taking highway clover leaves aggressively I never broke traction with PS4Ss.

 

[GooberDH]

Definitely take chat GPTs word for it.

Gotta love GPT.

"This is good and works well"

But isn't that totally wrong?

"You are absolutely correct"

 

[Junkyard Dog]

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