davemon

Hi All! I'm a new guy here and have done a little reading and am trying to compile a list of wheel options for my 2005 C2S. Options change over time so I am trying to see what is current.

My car has the 19" staggered S wheels and I'm considering a second set with something like a Falken RT615, Pilot Sport Cup, or similar for summer fun and autox and light track use. I've tried my car out in the rain and the dry and found that on the stock setup it understeers more than I would like even for a street car. It's got 235/35R19 front and 295/30R19 Pilot Sport 2 tires on those stock wheels and the alignment has already been dialed for more front camber (the little one seems to be able to get from stock parts) and such.

I know the best solution would be a set of custom built forged wheels from Forgeline or someone. Had those on my last race car but GAWD were they expensive and worth it... want to go much more pedestrian on this car as I won't be competing so much as just plain having fun.

Questions:
- Can my car take any 18" or do the brake calipers make it a short list of
options?
- Can I change the tire sizes on the stock wheels to get less understeer or will a wider front set just lose sidewall rigidity or pinch in despite say going with a 245?
- Assuming 17" wheels won't clear the brakes. Correct?

I know nothing! I need to look up where the jack points are on this wonderful thing!

Dave

Edgy01

Jacks points were discussed recently. Go back no more than 3 pages.

You can take 18s, but 17s will not fit due to brake caliper clearance issues. I have no idea why you would want to run 17s, considering the car was optimized for 19s. The OEM 19" rims (Carrera S) are the lightest. Here's some wheel and tire weight info:

Porsche 997 Wheels

Porsche Factory Carrera S - 100 lbs, 0 oz.

8x19" 22 lbs. 4 oz.
11x19" 27 lbs. 12 oz.

Porsche Factory Carrera Classic - 104 lbs, 10 oz.

8x19" 23 lbs. 10 oz.
11x19" 28 lbs. 11 oz.

Porsche Factory Carrera Sport Design - 104 lbs, 12 oz.

8x19" 24 lbs. 3 oz.
11x19" 28 lbs. 3 oz.

Porsche Factory Carrera Sport - 106 lbs, 12 oz.

8.5x19" 24 lbs. 2 oz.
11.5x19" 29 lbs. 4 oz.

Forged Turbo Wheels - 102 lbs, 12 ozs.

8.5x19" 23 lbs. 8 oz
11x19" 27 lbs. 14 oz.

Porsche 997 GT3 - 110 lbs, 4 ozs.

8.5x19" 24 lbs. 5 oz.
12x19" 30 lbs. 13 oz.


8x19 (987, 997 non turbo front) 23.4 pounds
8.5x19 (997 turbo front) 23.9 pounds

9.5x19 (987 rear) 25 pounds
11x19 (997 turbo rear) 28.8 pounds

19x8.5 and 19x11 HRE Monoblocks (21#, 24#)

Carrera III Wheel Weights

8x18, 22.0 lbs
10x18, 24.9 lbs

http://members.rennlist.com/911pcars/WheelWts.html

Tire Weights:

Potenza RE050A 24/32
ContiSporrtContact 2 21/29
Pilot Sport PS2 22/28
P Zero Rosso 22/28
Advan Sport 24/30


Welcome aboard!

RonCT

A search here at the 997 forum will uncover lots of threads about wheel / tire options. Honestly, unless you are a very experienced track driver (ie: White run group in PCA), I'd avoid R-compound tires like the Pilot Sport Cups. On the street you'd only utilize maybe 50% of what they have to offer, while suffering much worse wear, feedback, safety margin, and wet performance. If you end up on the track, you will see just how potent the OEM PS2s really are. I get about 1.4 G lateral on PS2s compared with 1.5 to 1.6 for R-comps.

As to 19s vs. 18s - again, debated on and on for years here. To summarize, a great cost effective new wheel is the OZ Allgeggerita from Tire Rack in 8.5x18 and 11x18 (look them up via either 997 GT3 or 997 C2 - for some reason Tire Rack won't show 18s as an option for the C2S). Very inexpensive, very strong, very light - perfect!

Also, make sure you stick with the 25.5" front and 26.3" (or about that, say 26-26.5") rear tire diameter else you will impact your speedometer, odometer, PSM, possibly ABS, etc.

Regarding your understeer issue - has nothing to do with wheels and tires (ie: going with stickier tires won't help). It has everything to do with alignment and with the stock control arms you will only be able to get about -0.8 degrees of camber up front. Easy fix - GT3 Cup control arms and a better alignment. I run -2.3 degrees up front for my street / track hybrid alignment. Rides great on the street - very crisp steering response / turn in. Also minimizes the understeer. I have to ask - if you haven't been driving on the street, how would you know the car understeers? It takes a huge amount of pushing a car around a corner at full throttle to discover understeer in a stock set-up.

Good luck,
Ron

Leader

And if you want to put "pictures" to all the names/data posted above, here's a link to Wheel Enhancement's Porsche Wheels Page. Lots of good info there.

davemon

Thanks very much for the info guys and for the links where I've found a lot more info to help me get up to speed on the options out there. I've won a few autox title and road racing titles in other makes of cars and have been instructing since 2000 in cars. Background before that was dirt racing motorcycles and then road circuit motorcycle track stuff. I'm far from the fastest guy out there but I have held class track records in the past and while not as fast anymore I can put on some amusing drift shows and smoke screens at NHMS, LRP, and Tremblant. Just another amateur doing my best and having fun and marveling at the really fast guys! I'm not into racing anymore but do love track days on my motorcycles and in cars and hope to meet and learn from many of you. I yearn for those zen laps when everything is more perfect than any other lap I've ever done!

From that experience I am most likely not looking for Porsche factory wheels but it is way cool to know my S has the lightest regular factory wheels and that the car was designed for 19s. I don't know much about it but I really like the car so far.

As for the under-steer I've throttle over-steered in few fast sweepers and played with generating under-steer, then over-steer, and then back to under-steer in a single turn. It understeers much less and responds the throttle better with the sport button for the shocks on but still lacks front grip... or seems to compared to say the balance on a GT3-RS and GT3 cars I've driven on track that were still stock setups. It's ok but while teaching at an autox school I found it really plowed in the slow stuff like most stock suspended cars and I know my alignment was already tweaked by the previous owner for all the negative it could get up front (running close to zero toe to minimize tire wear).

I will look up those OZ 18s as I know how tough the track is on wheels and my stockers are GORGEOUS and the tire options are key too. I won't be aiming at Hoosier DOT slicks anymore as I don't care about lap times as much as I care about predictable wear and the ability to just be able to take the heat of 20 minute sessions for the few times I will do that with the car (most energy focused on motorcycles these days). Really liked the RT615 Azenis for driving to and from the track and on it with my last ride and would like something similar. They get a bit melted and drifty and then just stay like that and they don't make a hell of a lot of noise which I liked as I hate noisy squealing tires.

Dave

davemon

Those wheels look like the shizzle unless I find a nice set of junkyard dog wheels already sacrificed to the gods of burning brake pad bits! Have you driven a 997S with some wider rubber up front but otherwise the same? That was what I was thinking... either wider rubber or wider wheel with wider rubber. Probably not much according to my butt dyno but a bit more. I know this works wonders on M3's and some other cars with staggered setups (the BMW is staggered just to make less owners crash them I think ).

When I put in the GT3 it showed me a set of Front: Front: 235/40-18
Rear: 295/35-18 on 18x8.5 fronts and 18x12 rear O.Z. Alleggerita HLT wheels. You said 11 rears and I am guessing you probably are in the know that the 12s won't fit the C2S but the 11 is the ticket right?

I just noticed you're car list and hobbies! Nice! You clearly already understand a messed up character like me and we are probably both attending the same 12 step program unsuccessfully. (my wife and the judge sent me but I still bought the C2S and have a collection of extra wheels and tires for my track bike ).

I totally hear you on the PS2s as they ROCK as tires but would like some cheaper skins for the track and preferably something like the RT615 with way less tread squirm and longer wear on track. Haven't tried the PS2 on this car but they did blister and tear up when I last drove a car in anger on track with them (fairly stock E46 M3 with suspension) although they were predictable and loud.

Dave

RonCT

Dave,
The jury is still out on 11 or 12" for the tires on the GT3 / C2S. Both cars are the same narrow body design. I still don't understand why Porsche put a big, wide, heavy wheel on the GT3 (I had one). When you look at the tires you plan to use, you'll see what wheel width is suggested. For me, the widest I go with on the rear is 305, so the 11" is a great fit for it and is clearly a lighter wheel than a 12".

I've run 235/305 19" Cups, 245/305 18" RA1s, and now 245/305 19" R888. All on 8.5" front wheels and 11" rears and have been very happy with the setups.

mdrums

+1, Ron you beat me to it!

davemon

Thanks again! I am learning and boy oh boy do I need it. It sounds like you are way fast at the helm and have lots of days so your advice is extra good for me.

Cool, that makes sense and given that my car has more understeer than I desire already... 12" on the rear would make no sense, 11s are for me. On top of that this is the first car I've owned in a long time with a limited slip differential so it seems like it would be extra silly to add larger wheels and tires to the back end.

If you wanted nice, non-squeally, predictable, fun tires to drive to and from the track and wanted to get say 6-8+ days out of them what would you pick out of the ones you've tried?

Are these the GT3 front control arms?
http://e-partssales.com/Merchant2/me...de=986996FrACA

OH how I wish I had paid attention in the many 997s I've driven on track that weren't mine!! I was focused on the students and making sure they had fun and learned some new stuff safely though. I've got to knock that off!

Dave

obsessedone

Ron

Most recommend 18" track wheels. Looked at tire rack and don't see tire combinations for 18" wheels that maintain stock tire diameters for 2006 C2S in mich Sport Cups or Hoosier R6, am I missing something, or for the CS2 do I need to stick with 19" to use Cups or Hoosiers?

RonCT

Those look like the right control arms, but I'd trust the decision to my local Porsche race shop who would be installing and getting the parts.

There aren't many (if any) rear tires at Tire Rack that have the right diameter for 997 / 987 Porsche products because for some unknown reason Porsche decided they wanted to change from a 25.5" rear wheel diameter (like the rest of the world uses) to a 26.3". But of course the N-specification Porsche approved Michelin and Pirelli tires have the right diameter...

For somebody not in the advanced group, I'd strongly suggest a set of max-performance summer tires for track use. Learn the car and have some great feedback from the tires (vs. having them snap on you if R-compound). There are plenty of tires, at tire rack as well, that have the 26.3" rear diameter.

Looking for that 1-st DOT specification R-compound, the Toyo R888 (or the RA1 if you can find them still) have the 245/305 combination that are about 25.5 front and 26.3 rear diameter in both 18 and 19".

MikeBat

Another two choices of tire worth looking into are the Dunlop Dierzza Star Spec and the Yoko Neovo 07/08.

Both are just a notch under R compounds in terms of grip but have better wear (around 200 vs 100 for R's).

obsessedone

Ron

Thanks for input. Running white group on PS2s and after 15-20 minutes they are very "oily" making the end of 20 & 30 minute sessions interesting. Plan to go Cups or Hoosiers but trying to make wheel size decision. Most recommend 18" for more tire choices and cheaper tires, but for 997S seems like very few 18" options, maybe getting second set of 19" wheels makes more sense, could run the Cups or Hoosiers on dry track and my PS2s if hit rain.

luisimo

Lots of great info here, thank you everyone!