Correct tire size question

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Originally Posted by KRAM36

Well you learned something today again then. On a alignment for street car, the tire rotation makes a big difference when you decide to go for a spirited drive. No my car does not need an alignment as I can fell the twitchyness changing the front tire to a smaller faster rotating speed.

People that race, align their cars much different then street cars. Alignments good for race cars are not good for street cars, if you want to have proper tire wear.

"All 987, 997, 981, 991 run 1" smaller diameter in front than the rear."? You are completely wrong in this statement.

Negative ghostrider, stock 981 Boxsters typically run 26" diameter in front and 27" diameter in rear. I ride right seat in a LOT of 987/997/981/991 cars at the race track as an instructor. No twitch, no unusual tire wear as long as the alignment was set up for the type of driving they do.

I drove my street 986 for 10 years and 100 track days experimenting with a lot of different tire sizes, no twitch unless I had too much rear sway bar.

Here are stock sizes for a 2013 Boxster. Note the difference F/R in diameter and revs per mi. Different sizes, no twitch.
https://www.tirerack.com/tires/tires.jsp?tireMake=Bridgestone&tireModel=Potenza+RE-71R&frontTire=345WR8RE71R&rearTire=645WR8RE71RXL&vehicleSearch=true&fromCompare1=yes&autoMake=Porsche&autoYear=2013&autoModel=Boxster&autoModClar=


My 2009 Cayman runs 25"F, 26"R as stock sizes.
https://www.tirerack.com/tires/tires.jsp?tireMake=Michelin&tireModel=Pilot+Sport+4S&frontTire=34YR8PS4SXL&rearTire=64YR8PS4SXL&vehicleSearch=true&fromCompare1=yes&autoMake=Porsche&autoYear=2009&autoModel=Cayman&autoModClar=

Here are stock sizes for a 987.2 Carrera. 25"F, 26" R
https://www.tirerack.com/tires/tires.jsp?tireMake=Michelin&tireModel=Pilot+Sport+PS2&frontTire=34YR8SPTPS2XLN4&rearTire=64YR8SPORTPS2XLN4&vehicleSearch=true&fromCompare1=yes&autoMake=Porsche&autoYear=2009&autoModel=911%20Carrera%20Coupe&autoModClar=

I think somebody has been yanking your chain a bit KRAM.