HenryPcar

My 997.2 needs new shoes. The original rear tire size is 295-30-19. However, Tirerack listed an additional size 305-30-19.
My question is can I use the 305 instead of 295 and what are the pros and cons. I don't track the car, but do occasionally drive like I stole it :>).

okbarnett

10mm difference

lowpue

MIne came with 305 stock from dealer....

BaileyII

Type 2

The 305/30/19 tire for your 997.2 is what used to be called a Plus One upgrade over original tire size in tire fitment. Note, however, a number of narrow body 997.2 Porsches came with 305s. On our 2012 Black Edition,997.2 Coupe, we moved from a 295 rear tire to a 305 rear tire on the 11"x19" Turbo II wheel.. There is no discernable change in handling (seat of the pants) on AutoX courses and with spirited/high speed driving. Some are of the opinion that the 305, looks better as the wheel well is fuller. If I remember correctly the 305s were cheaper than 295s on Tirerack., when our 305s were purchased several years ago.

HenryPcar

My 295 already looks pretty full within the wheel well. I'm not too sure the +1 305 give me any advantage other than, strangely enough, lower price tag. My 295 only lasted me 15K miles and the inside shoulder already went bald. If anything the 305 will wear out the inside even faster due to its wider stance. Thanks for the information.

Edgy01

When the 997 came out it was mostly equipped with the 295 rears, on 11 inch wide wheels. Then late to the 2006 model year they added the XRR option--Carrera Sport Wheel--11.5 inch rears, which came with the 305 tire. Either is fine. Most of us are simply not that sophisticated in our driving skill levels to feel a 10mm difference. I know I wouldn't be able to.

nwGTS

price for one and possibly a chubby look like someone mentioned depending on your wheel width
you mentioned no tracking but on track you can feel sidewall flex on wider tires on the same wheel width as a narrower tire... just means more preload and need to turn in earlier to account for the preload.

Petza914

A +1 upgrade signifies a change from a smaller diameter wheel to one that's a 1" larger diameter, and then a lower aspect ratio # to keep the rolling circumference the same, not to a wider tire width.

305s are a little wide for an 11" wheel. If running am 11.5" like a Champion or a 12" GT3 NB wheel, then the 305s are perfect. Will they work on an 11" wide wheel, yes - are they ideal, no. I run 305 rears on both my 997s but both have 12" wide rear wheels - GT3 & Forgeline. I also ran a 305 on my 11.5" wide Champion RS171s .

bhvrdr

Technically a 305 from michelin, perelli, and Bridgestone are speced perfectly for an 11" wide wheel. According to their manufacturers a 12" wheel is actually too wide for them but Porsche says otherwise. I agree i like them on an 11.5" wheel but no issues on an 11"

https://m.tirerack.com/tires/Spec.jsp?tireMake=Michelin&tireModel=Pilot+Sport+4S&partnum=03YR9PS4SXL

Type 2

Agreed, and my earlier post stands corrected. "Plus One fitment" from Tirerack Tech's section reads in part: " Plus Sizing dates back to the 1970s when Plus One and Plus Two fitments were the available choices. Drivers could upgrade their cars from relatively narrow 13-, 14- or 15-inch wheels and tires up to wider 14-, 15- or 16-inch combinations. While Plus One and Plus Two are still popular today, the starting point now typically begins with 15- or 16-inch wheel diameters and grows from there.

Plus Sizing supports the premise that it's important to maintain the same overall tire diameter whenever changing tires and wheel sizes to ensure sufficient ground clearance, appropriate driveline gearing and accurate speedometer readings. ...." Thanks for the correction. Type 2

Petza914

No worries. None of us knows everything and gets it right 100% of the time.

HenryPcar

Great information here. Thanks, my 997.2 comes with 295s and I'll stick with it.

BIG smoke

I have run three sets of 295 on the rear, and one rear set of 305's.
I couldn't tell the difference. 10mm on a 295, is 3% bigger.
I see, slightly more meat, maybe sticking out a little more from the rim.
AND, a little more padding from that attack curb.

Fined

running 325/30ZR-19 out back on 12" wide wheel. I'm digging it. nice meaty look and noticed a bit more stability when I first made the move a couple years ago.