delta3

Hi, is it ok to run 305/30/19 rear tires on 7.2RS? does anyone have experience? all else is stock (wheels, front tires, chassis), with -2 front and rear camber.
1. does the smaller circumference throw off any electronics?
2. does it alter handling characteristics for better or worse?
3. if I were to use this smaller size, does it require a different tire pressure? (less tire supporting the same weight)
thanks in advance!

Burren

305s on a 7.2 non-rs fit just fine.

RAudi Driver

The real question is.... WHY?

delta3

tire choice. in my area i currently only have ps4s, cup2 and trofeoR available for 325 rears. I'd like to use other tires if possible, but some only go up to 305 or 315.

vma1788

If you are going to be running the same wheels, going down to a 305 will result is a really stretched looking sidewall which will look odd all things constant. Maybe bump down to a 10.5 rear wheel and get some weight savings while youre at it.

ngng

305 should be fine. Not all 305s are the same "real" width though, so be sure to measure. I've run 335 RA1s before running a smaller NT01.

mezgermischief

I recently ran into the same issue, I couldn't find a tire for my street setup where the front and rear were square (245=9, 325=12). I ended up going with Yokohama v601s as I adore them for the road, and they are cheap enough that I could wait out the backorders with an albeit goofy looking setup. The largest rear they have in stock is 305/30r19 so I got 235/35r19 for the fronts to match the predictable stretch of the rears.
I was surprised with how it turned out. Looks very OEM+, with a minor stretch.
Greatly improved road/steering/brake feel, far more engaging and enjoyable compared to the square PS4S setup I ran prior.

F: 19x9 235/35R19 R:19x12 305/30R19
Yokohama Advan Apex v601

jason95R

Interesting to hear your review of the Yokohama's compared to the PS4S. When my Cup2's wear out I was set on the 4S since I only street drive my car. I'll have to look into those.

I see you're from CT. Me too. Maybe I'll see you around.

mezgermischief

If you are ever in Fairfield County I'd be glad to let you drive and see how you like them. I also have a set of lightly used PS4S N0 spec if you are interested (325/30r19 & 245/35r19).
The v601 is a really special tire to me. Soul/character is what makes driving enjoyable, and I find the sidewalls of PS4S greatly take away engagement. They a numb, subdued, they distance the driver from the road, they lack the sidewall rigidity adorned with 200 tread-wear tires. And as much as I adore running 200 UTQG tires, I adore being able to rip around wherever and whenever, and I have finally matured enough to realize Cup 2s, rt660s etc take away from the feasibility of that.
The v601 is what I feel as being a hybrid between the track day specials (trofeo, cup 2 etc) and the "sporty" street category to the likes of PS4S. Tire manufacturers want to appeal to the largest audience and by that, the sector of "enthusiast, who enjoys emotion and some sliding during the wet" has largely remained empty. Either you have to choose to forgo all hydroplaning forgiveness that comes with a 200 UTQG or forgo feedback and character when going with 300+ UTQG. The v601 may not be as "comfy" or "composed" as the PS4S but is that what we really want for a GT car. You can dance a little more and thats what I love, the tire doesn't pretend to take the kids to school and rip around backroads on the way home, it knows what it wants to be and is great at doing so. Hope this helps.

CRex

Don't forget the 997.1 RS actually ran a stretched 305 tire on 12J rims. I remember reading an interview that mentioned it was a conscious decision back then--the stretching (marginally) increased the contact patch of the 305 and the car didn't need the extra weight of the 325 tire.

So if you're okay with the "bubble" look, go with the compound of your choice!

delta3

thanks for the replies! the stretched tire looks don't matter. i'm more concerned about and unsure if there will be any interference with electronic safety systems or changes to handling characteristics.

theoretically, with smaller circumference rears, it will require more revs than before compared with the same front tires and the tcs might interpret that as slippage and cut power. but since the difference is only 2%, maybe it's not enough to trigger any systems. with less grip in the rear, i wonder if the rear will be too unstable?

people with experience or expertise, please chime in, thanks! i'm hoping i can do 245/305.

mezgermischief

This is a tricky one as I don't want to make assumptions and put you in a bad position.... but, I have had zero issues, and my general experience has been again much better than PS4S 325/30 & 245/35. I do however run the car with TC and PSM turned off. The difference in angular rotation from this slight downsize is insignificant in terms of an increase in inertia, that isn't to be said that there are zero differences, where some very sensitive AWD systems etc in some cars may result in marginal changes in characteristics, the 997s suspension geometry and drivetrain/diff setup is arguably unaffected.
I would experience somewhat significant wheel-hop in mixed-weather conditions when driving hard with my prior PS4S setup (which is never good!), the new setup does not result in this. Whether the change in diameter is resulting in a better relation between the cars suspension and its ability to put power down, or rather simply in result of a change in compound, that I am unsure of. Hope this helps.

jason95R

Thanks! All great info. If I'm down in Fairfield County I'll let you know. I live just west of the Farmington Valley and not down there much.

My Cup 2's only have about 3,000 miles on them at this point and are only 2 years old. So going to be a while till I wear them out.

Breakthru

I'm running 325s on my rears. Prefer it over the stretched 305s (which were on when I purchased the car)...just my preference.

bweSteve

Question: Do the 997.2 3RS cars have 12" rear rims just like the narrow body cars? (just with a different offset)