jakermc

Looking to pick up a set of 18" wheels with the intent of running NT01 for track days. Trick is I am currently running PCCB set-up so I understand my choices are a bit limited. I think I read the CCW C10 will work? If so, will the following fit on my 997.1 GT3 and clear the brakes:

18x9 +48, 19 lbs
18x11 +60, 20.5 lbs


I know the 11" in the rear is also a bit narrow, but looks like that's what Nitto used for their measured widths on their website. Thanks for any insight ...

Protocav

I use the 305/35-18 NT-01 and it fit's square on a 12" wide wheel. It wouldn't seat right on an 11" wheel, and it would look funny.

That front offset is fine, but i can tell you that it will be very close to the spring on the inside. Offset is not a good way to tell if the wheel will clear the brakes because it depends on the spoke profile and the depth/position of the drop center. The wheel mfr should be able to provide you with a 1:1 template of the wheel profile, or you could ask them.

85Gold

Just talk to John at CCW and he will steer you straight. 315's fit just fine on 11" rims.

Peter

johnwb

I was able to get an 18" OZ Challenge wheel to clear my PCCBs.
CCW should be able to make a wheel that works for you.

jakermc

I know CCW can do it but with 3 non-license plate racing cars already draining my budget I am trying very hard not to go down that slippery slope with the street car. Just looking for serviceable set of 18" wheels so I can have a better selection of track day rubber when I want to have fun in the GT3 versus moving the race rig to the track.

The OZ Challenge looks like an affordable option. What widths and offsets were you running? Where did you buy them from?

DC640

If you go to tirerack and pick Ceramic brakes on 997.1 gt3, OZ challenge wheel disappears. I asked tirerack people... they said no.

I ended up with CCW wheels on 997.2 after 5 lug conversion. Cheapest custome wheels i can find.. plus John @ CCW has great service.

mooty

any form of GT3 should run 12" rear. if not, you are defeating the purpose of changing wheels no?

if OZ fit, that's cheap and great but i am not so sure on pccb.
if not, take CCW. 28-2900/set, nothing comes close.

jakermc

Not necessarily. If you can run the same size tire on a smaller rim, you'll get the same footprint (small difference not noticeable by mere mortals) and less weight. Often times spreading a tire over a wider rim makes the sidewall less effective. So I would say no hard and fast rule, I always look to the tire manufacture's specified range first as a guide for acceptable min/max rim size for a specified tire size and go from there.

Current price for CCW C10 in our sizes is $2,950 according to website. They do make a great wheel, I run them on my 911 race car. And yes, John's service is spectacular. One day turnaround to repair 3 piece wheels!

mooty

good to know. thx for the education!

Protocav

(I don't intend to start a debate and truly only intend to steer you in the right direction) Most of the time it makes it more effective, since it triangulates the sidewall and you can more easily tune your suspension. If the tire bulges over the rim, it is more prone to rolling over and gives a mushy feeling. Having the sidewall square or slightly stretched makes it more stable. This is not a catch-all, however, because some tires have stiff, and some have soft sidewalls. More important for softer sidewalls, for sure.

997gt3north

This is my understanding as to why Porsche went from an 11" to a 12" on the 997 vs 996gt3 - most tires back when the 997gt3 were released, even on the 305 spec tire, listed an 11.5 inch rim as the MAX rim spec to use - and yet Porsche shipped the car with a 12.

You will be fine with an 11" - 12 would be better since we are not racing F1 who cares.

The 60ET 11" will also be 'fine' - but I think you are likely going to want to run a 15mm spacer if you remove the OE 5mm spacer.

mdrums

its better to square off the side wall than undersize it with a skinny wheel. This will keep any extra sidewall slop down.

jakermc

I think we are all saying the same thing, but perhaps the difference is I rely more on the tire manufacture's specified range, where the midpoint is typically ideal, rather than what Porsche spec'ed for their wheel.

As mentioned, given the same size, different tires will want different rim widths based on how sidewall was designed. Remember that the Michelin spec'ed with the car is not a true R-compound. I have not driven on one in a while, but I suspect its sidewall is softer than the other options out there. Then there is the whole change from a 19" wheel to an 18" wheel, the resulting increase in sidewall height, and suddenly there are lots of moving variables!

Porsche is in the business of selling cars, and hey, 12" rims must be cooler than 11" rims. I don't put their combination of 12" and 305 tire much beyond that. As 997GT3north says anything in the 11"-12" range will work well for a bunch of hacks in a DE.

mdrums

I have run Toyo RA1, R888 and Nitto NT01 and Michelin Sport Cups in 305s' and all say 11.5" max but I've run each tire on a 12" wide rim. Zero issues. Porsche even puts a 305 on a 12" rim from the factory.

If you feel weird about doing this you should do at least a 11.5" rim. 9" up front and 11.5" rear is fine. If you are not doing a 12" rim due to weight it makes no sense. There is more difference in tire weights than a .5" rim width difference.

jakermc

NT01 305 size has recommended rim width of 10" to 12" with 11" being used for all quoted specs, such as tread width. Check out their website for full specs.

Same tire on smaller rim if unsprung weight is a concern makes perfect sense. But yes, if switching tires brands or sizes thatalso needs to be considered.