911F1

I have the stock Pirelli Pzero 295 30 20 in the rear right now. They're pretty much shot from doing Autocross events. Thinking of going to 305's on the rear and keeping the 245's up front. Has anyone gone to 305's from 295 and noticed any difference in handling? I know some sport wheels already have 305's as a standard tire. I have the 20" Carrera S wheels. Thanks for responding!

chuckbdc

The 305s that Porsche delivers are on half inch wider wheels with different offsets (on the SportTechno wheels and on your style wheels that come with the C4S).

I have no idea if going from 295 to 305 will be better or worse in your case, but it is not a sure thing it will be better.

robsc2s

If you refer to recent post " spacers on 50th", all porsche oem wheels are listed ( courtesy Suzy). Appears c2s and c4s rear wheels are 11" ( albeit with different offsets )however have different tire width. Includes both classic and s style.

Team Plutonium

I went from 295 (20") to 305's (19", and back again to 295's because I switched rims yet again. No difference in handling one way or the other.

Hammer911

You will notice $ difference when you wear out tires!

chuck911

94 is right. 305 is 3.49% wider than 295. Are your tire pressures, and driving skills, so perfect that you will notice 3.49%? Yes theoretically there will be more grip. They will also roll a bit more, feel a bit less responsive, and store (and release) a bit more lateral energy in transitions. Which I hear there are a lot of in autocross. But to put in perspective, aside from the 3.49% angle, a new set of tires always feels different (and being newer rubber grips better) than old, differences that are almost certainly much greater than the difference between these two tire sizes. My guess is you might feel the difference. But which one you prefer is anyone's guess.

DallasDave

On my .2 I went from 295 to 305 and was very happy with the grip of the Super Sports vs PS2's. I will be up-sizing to 305 Super Sports on the 991 when the Pirellis get worn.

Dave in Dallas

LexVan

One of the main reasons I wanted Sport Techno wheels..... you get the 305 rear tire automatically. I did not want to have rear tire envy.

Slantnose!

Good choice!
I want 335's

lunarx

^^ Yup.
I noticed 305 are not wide enough.
The 991 still oversteers.

John's 991

It is unlikely that you will notice any difference in mechanical grip between a 295 and 305. It is also desirable to have the tire sidewall in line with the rim, and not wider as this makes the sidewall stiffer. When the tire is much wider than the rim, it can "bow" out and introduce flex. Not sure that a 305 is wide enough for this to be a problem though.

The MPSS do seem to grip much better than the P0, at least in my personal experience. That is a worthwhile performance upgrade.

However, if you have tire envy or just like the look, I have heard the wider tires fit, but that's second hand info.

911F1

Thats a good point. I think I'm going to stick with the 295's. I'm ok with the way it looks and handling benefits are probably minimal. I run in a stock class and bumping up to 305s might be a penalty.

chuckbdc

Good move. Contrary to popular belief, wider tires do not equal more contact patch. You can easily "tune to driving style" with tire pressure differences front to rear. PS I just went from P0s to MSS and am loving the Supersports.

John's 991

Chuck, yeah I found the same thing. Significantly better, especially when under 40psi hot.

Buck366

I guess the 305 will work fine? No rubbing? Thinking of bumping up from the 295.