jamal08

Hello everyone, I am a bit stuck right now. I recently purchased an 06 911 s but one of the rear tires had a blow out. It came on PES GP7 Monolite's. Rears are 19x11.5 44mm offset. It currently has 315/25r19's in the rear but it seems that everyone has discontinued that size or whoever still shows they have the proxes t1r's in that size are out of stock. Does anyone have an idea what is a different tire size I could run in the rear? Thank you in advance for all the help will be nice to be able to finally drive the car further than from the driveway into the garage

rileyracing1

315's in the rear of a 06 S?? am I missing something here ?? Why so big and what for ?? aren't those rims /size designed for a wide body 997 ?

I would start with the link below and get proper size tires and rims if need be for that car.

https://tiresize.com/tires/Porsche/911/

Chalkboss

Thread right below to address your question

https://rennlist.com/forums/997-forum/1265568-2009-4s-wheel-size.html

jamal08

lol yeah 315's in rear on an s I was amazed when I saw the car in person and that was the size. Didn't think that would fit on a narrow body but I guess it does. I am wanting to try and keep the rims it has on it but don't know much about tire sizes to know what I can change to

jamal08

Good info on that thread but mostly they are talking about a 4s it seems unless I am misreading. I did see the chart showing for an s stock setup one option is 305/30r19 for rear. Maybe that will be best option to switch to it seems

jamesinger

I would run 305s.
I had 305s on the lobster forks for my 06 C2S. I run 305s now on OEM GT3 wheels with the 19x12s.
NB cars can fit 325s even but that doesn't mean one should, especially on 19x11.5 wheels. Porsche picked their tire sizes pretty well. My friend was running Cup 2 315s on his OEM GT3 wheels and they did not look as good or corner as good as the same tire in OEM 305 sizes IMO and to his...he ended up going back to the 305s.
From my understanding the C4S wheels are the same width as on the C2S but with a lower offset.

Petza914

The next set of tires on my C2S will be 245/40-19s on the front and 325/30-19 on the rear. This results in a 26.73 / 26.77 diameter ratio or a 1.0. Stock sizes of 235/35-19 and 305/30-19 give a 25.5 / 26.2 ratio or 0.97. They are slightly taller which will eliminate the 2 MPH too high speedometer reading all of our cars have (your spoilers actually go up at 75 MPH even though it shows 77 MPH on your speedo).

OP, if your fronts are still good, just put on 305/30-19s until it's time to replace fronts and rears then analyze the ratios again. My rears are 12" wide, but your 11.5s will be fine too.

Khloesdad

I'm running 305's very happily. Non WB.

Ironman88

I just ordered 245/35-19's for the front, and 325/30-19's for the rear. Surprisingly longer wait to get them than I had anticipated. Fronts will be about 2 weeks. The rears won't be in until the end of Sept.

My car is a C2S.

I've been waiting to get the new wheels / tires on the car since January. (Wheels had to be restored / rebuilt.) Can't wait to get them!

Khloesdad

^^^^^^^^^^^Jeez, for a second I thought I clicked on ****.

Petza914

Those are going to look great. Loved the brushed silver centers and polished lips.

A 245/35-19 has a diameter of 24.3. paired with the 325/30 that's going to give you a R:F ratio of 26.77 / 24.3 = 1.10 or the other way 0.91 - that's a 9% difference in front tire diameter vs rear tire diameter. I think this is going to cause you problems with the ABS & PSM systems - the target to keep those happy is around 3%. That's even more important on AWD cars so the transfer case doesn't get destroyed (but know yours isn't).

For that size rear, I think you need to go with the larger front I mentioned of a 245/40 at 26.73 diameter. That compared to the rear of 26.77 is almost a 1:1 relationship and much better match. 26.73 / 26.77 = 0.999

Since there's a delay in getting the tires shipped, maybe you have time to adjust the order if you think you should. Otherwise, I'll be interested to see how this pairing works and whether the PSM is frequently intervening or not.

Ironman88

Thanks Pete.

I think GTS Sully is running these sizes on his car (the sizes I relayed.) I'll verify with him if he's having any issues or not. Otherwise, I'll see about changing the order for the fronts.

I'll reply back after I contact GTS Sully.

Thanks again.

Ironman88

Pete,

I checked with GTS Sully and he has the 245/35's on the front, with the 325/30's on the rear. He's not had any issues with them.

That being said, I did go ahead based on your message above and changed my tire order for the fronts to the 245/40 - 19's. (I know you have researched this thoroughly.)

Hopefully everything will work out ok with this.

Thanks.

Petza914

Great info. Thanks

jamal08

Thank you everyone for all of the information. I ended up going with stock size of 305/30r19 rear and 235/35r19 fronts. Fronts are low so thought may as well switch out all around since I wasn't getting same tire in rear as what is currently in front. Definitely not a lot of options out there for these sizes if you want tires anytime soon as others have experienced. This on going logistics issue and adding the rubber shortage on top is for sure making things not easy. Most places I called said they wouldn't have ps4's for over a month and supposedly Michelin has slowed down production (not sure how much I believe this statement lol)