^ Nerds R-U-L-E

+ 1 for Nerds. Although we may be alone in that sentiment. We should wake up a few members and ask.

Geeks are the "new chic" LMAO

erubin - the problem with the wheels you currently have they are so damn light they are hard to beat anywhere. I have the same ones!!!! It is the lightest wheel Porsche has offered in 18-19"

18s over 19s but the 19s look pretty damn good : )

Definitely makes the choice more difficult.

The weight/radius density of the tire construction has been negated in some of the "goesintas" here. Porsche has figure out that the 19" is a faster set up. Extrapolating on the caculations and conclusions here the 17' wheel set up would be even lighter - hummm... Let's see those slide rules prove me (and Porsche) wrong! - (all in fun)

I think you are referring to the following formula:

Y= 2(X+Z)+3(goesintas-1.333)

Y= fastest Wheel
X= Weight of wheel 1
Z= Weight of wheel 2

you forgot to divide by pie - the all encompassing factor!

You are absolutely correct but I could'nt get the symbol for Pi to come up in the reply to thread panel so I just left it out. Secondly I could'nt decide which flavor.

I don't think so. Even the 996 GT3 came with 18's stock.

If you look at the 997 GT3 it does come from the factory with 19's, but if you reall want to know what's faster take a look at the race car (997 GT3 Cup).

Wanna guess what that rolls on???? 18's.......

I have not looked, but part of that could be impacted by the availability of 19" race compound tires from their sponsor.

Here's the pie for your equation (cherry):

Beyond weight, I don't think the 17" wheels with higher apect ratio tires will be as stiff as an 18" wheel with its lower aspect ratio tires. This could affect the overall lap times. 19" seems to move the weight further from the center so the 18" wheels seem like best compromise.

Your really stretching here. Race rubber is plentiful in multiple sizes in 18" and 19" diameters. Furthermore, Porsche could certainly ask tire manufacturers to make whatever size tire they wanted (just look at all the "N" spec tires Porsche has them build).

Perhaps, Porsche put's 18's on the 997 GT3 Cup because that is what's fast. Still not convinced. What do you this the fastest 911 Porsche makes wears (the 2008 GT3 RSR)????? 18's again!!

If you head out to your nearest local DE, you'll also notice that many 997 GT3 and GT3 RS owners swap the factory 19" wheels for 18's.

Hmmmm, I wonder why they do that????

Tire - 285/30R18 >Search Tires Tire 1 - 305/30R19 >Search Tires Tire 2 - 285/35R18 >Search Tires Tire 3 - 305/25R19 >Search Tires Section Width:11.22 in285 mmSection Width:12.00 in305 mmSection Width:11.22 in285 mmSection Width:12.00 in305 mmRim Diameter:18 in457.2 mmRim Diameter:19 in482.6 mmRim Diameter:18 in457.2 mmRim Diameter:19 in482.6 mmRim Width Range:10 - 11 inRim Width Range:10.5 - 11.5 inRim Width Range:9.5 - 11 inRim Width Range:11.5 - 12.5 inOverall Diameter:24.73 in628.14 mmOverall Diameter:26.20 in665.48 mmOverall Diameter:25.85 in656.59 mmOverall Diameter:25.00 in635 mmSidewall Height:3.36 in85.344 mmSidewall Height:3.60 in91.44 mmSidewall Height:3.92 in99.568 mmSidewall Height:3.00 in76.2 mmRadius:12.36 in313.94 mmRadius:13.10 in332.74 mmRadius:12.92 in328.16 mmRadius:12.50 in317.5 mmCircumference:77.69 in1973.3 mmCircumference:82.30 in2090.4 mmCircumference:81.21 in2062.7 mmCircumference:78.53 in1994.6 mmRevs per Mile:841.0Revs per Mile:793.8Revs per Mile:804.6Revs per Mile:832Actual Speed:60 mph100 km/hSpeedometer1:56.6 mph94.3 km/hSpeedometer1:57.4 mph95.6 km/hSpeedometer1:59.3 mph98.9 km/hSpeedometer Difference: -Speedometer Difference: 5.946% too slowSpeedometer Difference: 4.523% too slowSpeedometer Difference: 1.081% too slowDiameter Difference: -Diameter Difference: 5.62%Diameter Difference: 4.34%Diameter Difference: 1.08%


The 25 is the best match for the stock C4S rear - why has that not been entered into the mix?