Very specific Porsche wheel sizing question

[KRAM36]

Originally Posted by geetee

^^ sure

Can you elaborate more?

[Acast94]

I just purchased 12mm & 20mm hubcentric spacers
I think the tires I will run are 235/35R19 and 275/30R19

[KRAM36]

Originally Posted by Acast94

I just purchased 12mm & 20mm hubcentric spacers
I think the tires I will run are 235/35R19 and 275/30R19

Did you get the correct length lug bolts also?

[Nine8Six]

If you can get the rear tire in the 265 I'd say go for that instead. Those 19"x10 will be heavy for that little flat 6, Porsche wheels or not. If you can find any ways to save weight on the rear wheels, do it.

Not that it would make a huge difference compared with the 275, but it will sure help a bit

[KRAM36]

Originally Posted by Nine8Six

If you can get the rear tire in the 265 I'd say go for that instead. Those 19"x10 will be heavy for that little flat 6, Porsche wheels or not. If you can find any ways to save weight on the rear wheels, do it.

Not that it would make a huge difference compared with the 275, but it will sure help a bit

That makes a big change in the driving characteristics. Takes away the near identical ration speed between the front and rear tires, less sidewall on the 265, which would ride rougher and possibly make the car feel not near as planted in the rear while cornering and hitting bumps. Just doesn't seem worth it to me to give up better handling for a little weight saving in the tire. Like I said before, plenty of ways to add power then to give up the better handling. These cars were not rocket ships in the first place. If you want that, do some mods!

[Nine8Six]

I see, was just trying to save our friend here 1~2kg on the rear end. Dunno about handling... my forged ADV6 (V1 SL Series) are lighter than the stock wheels that came with that car. So light I can do wheelies when passing over speed bumps.

Grip, ah that. the trick is to find the cheapest possible tires you can find(in China!) and warm them up real good before hitting it. The rubber "melts" basically: Velcro-mode-ON! Excellent for the dusty Shanghai industrial Park, early Sunday morning, 0400am, cops & kids sleeping....

Is that what you meant by driving characteristic?

[JayG]

If you don't have PSM, why would the rotational speed of the front vs rear matter?

[KRAM36]

Originally Posted by JayG

If you don't have PSM, why would the rotational speed of the front vs rear matter?

If your front tires are rotating at a different speed then the rear, you will get a unbalanced feeling when turning. I can feel it when I go from my summer tires to my winter tires. On my winter tires the front and rear tires spin at much different speeds and steering input needed is way more then I like. It just doesn't feel as stable and balanced with you constantly having more input into the steering wheel. My front winter and summer tires rotate at the same speed (so I am used to the rotation speed of the front tires) the summer and winter rear tires do not rotate at the same speed. With my summer tires rotating at near identical speeds (1km per rotation difference in rotation speed) the unbalanced feeling is gone and rolling thru corners is a breeze with less input needed to the steering wheel. Completely different feeling of security while cornering. I can even feel this when changing lanes on the highway, just not a good balanced feeling to me.

That's my personal experience and I will always try to get the front and rear tires spinning at the closest speeds possible.

[KRAM36]

Originally Posted by Nine8Six

I see, was just trying to save our friend here 1~2kg on the rear end. Dunno about handling... my forged ADV6 (V1 SL Series) are lighter than the stock wheels that came with that car. So light I can do wheelies when passing over speed bumps.

Grip, ah that. the trick is to find the cheapest possible tires you can find(in China!) and warm them up real good before hitting it. The rubber "melts" basically: Velcro-mode-ON! Excellent for the dusty Shanghai industrial Park, early Sunday morning, 0400am, cops & kids sleeping....

Is that what you meant by driving characteristic?

I think the weight difference actually depends on the tire manufacture and performance series.

Looking at General Tires G-MAX AS-03 tire, Tirerack shows the 265 weighs 1 lbs less then the 275, but their 275 weighs only 24 lbs. Click on specs.

https://www.tirerack.com/tires/tires.jsp?tireMake=General&tireModel=G-MAX+AS-03&frontTire=63WR9GMAS03XL&rearTire=73WR9GMAS03XL&vehicleSearch=false&fromCompare1=yes

Looking at Sumitomo HTR Z III tires, Tirerack shows the 265 weighs 1 lbs more then the 275 series. Click on specs.

https://www.tirerack.com/tires/tires.jsp?tireMake=Sumitomo&tireModel=HTR+Z+III&frontTire=63YR9HTRZ3&rearTire=73YR9HTRZ3XL&vehicleSearch=false&fromCompare1=yes

Looking at Goodyear Eagle F1 Asymmetric 2, Tirerack shows the 265 weighs 1 lbs more then the 275 series. Click on specs.

https://www.tirerack.com/tires/tires.jsp?tireMake=Goodyear&tireModel=Eagle+F1+Asymmetric+2&frontTire=63YR9F1A2XL&rearTire=73YR9F1A2XL&vehicleSearch=false&fromCompare1=yes

Looking at Yokohama S.DRIVE tires, Tirerack shows both tires weigh the same at 26 lbs each. Click on specs.

https://www.tirerack.com/tires/tires.jsp?tireMake=Yokohama&tireModel=S.drive&frontTire=63YR9SXL&rearTire=73YR9SXL&vehicleSearch=false&fromCompare1=yes

Looking at Continental EXTREMECONTACT DW tires, Tirerack shows the 275 weighs 3 lbs more then the 265 series. Click on specs.

https://www.tirerack.com/tires/tires.jsp?tireMake=Continental&tireModel=ExtremeContact+DW&frontTire=63YR9ECDWXL&rearTire=73YR9ECDWXL&vehicleSearch=false&fromCompare1=yes

Is Tirerack correct on the weights?


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[Anker]

Your brake bias will also change resulting in diminished braking performance. The smaller diameter wheels will tend to lock up before the larger diameter ones.