8202632

i have a 2011 997.2s and purchased some 18" oem wheels for my next HPDE. Having an issue finding matching fronts and rears for tires.

My stock wheels are 235/35-19 F and 295/30-19 rears.

New 18" inch wheels match the widths of the 19" wheels. Since the track wheels came from a 2005 C4S, tire rack is calling for 225/40-18 F and 295/30-18 in the rear. They have matching Toyo r888 in these sizes. Will this be adequate for the HPDE? The rolling diameters are not too far off, so I don't know if I'm overthinking this?

Or should I regroup and get rid of the 18's and find some 19's???

Thanks in advance!

J_D

Any help from the HPDE local club racers?

kisik

If you are not in advanced group, it would be fine and no need R-compound tires. You can bump fronts to 235/40. AD08R would be also great streetable tire. as well as R11, R71 from Bridgestone
If you are in > Black group, then we like NT01: 245/40 and 305/35 in 18" with at least 11" in rear and 8.5" front.

----------
997.1 C2S

cosm3os

Stick with 18s for the track

Hella-Buggin'

Won't you need spacers to adjust offsets since they came off of a C4S?
Most people in my events are running 18" track wheels because there are more advanced
high grip tire options available like NITTOS but that's changing. Like mentioned above, there's now several street tires available that offer pretty good options like the AD08R's and Michelin Sport Cups 2's.
Both come in 19".

8202632

The oem rear offsets for the 19x11s are 67 for my wheels. The 18x11s are 51 so it's like running a 16mm spacer.

Can anyone else chime in with a suggested size for the front and rears and a specific tire? Can I do 305s on the rear or should I stick with 285? Thanks?

Hella-Buggin'

For 11's wouldn't they be 295's?

8202632

Yes. 295s. Typo.

Jameshs

How much track work have you done and what suspension modifications do you currently have?

8202632

I do not have any suspension mods but have done 6 track events

Hella-Buggin'

With only six events under your belt you should stick with street tires. Sticky tire will shave a few seconds but will mask your mistakes. Also, sticky tires tend to let go less gradually then street tires. Learn to drive the snot out of street tires before moving up.

Our region breaks groups up like so:

Yellow = Student / Novice
Green = Intermediate
Blue = Experienced
Red = Instructor / Advanced

I'm in the Blue group and run AD08R's. Many in my group run NITTOS but in the lower run groups street tires are encouraged. Plus, with street tires you can track in the rain and learn a ton.

I have no suspension mods other than GT3 LCA's and a very aggressive alignment.

Alexandrius

I'm going to make it preety simple analysis since I've had a few beers and I love this topic. What I say is from experience of 20+ track days over about 2 years is as follows;

the cars were optimized with thousands of variables to go around a track as fast as possible, while providing as much comfort as possible.

this means you must consider many things when attempting to optimize "for track" by going to 18" wheels.

want to be faster on stock suspension? Use 19"s not 18's.

Why? You ask. Surely the added unsprung mass will slow me down ?

no; the 997 carera s is faster with 19s because alignment (can't get much better without making bigtime suspension changes) requires a lot of negative camber to fully take advantage of 18' wheels with a taller tire (as you must maintain overall wheel diameter).

If you dont achieve the requisite change in negative camber optimally (will cost $6k in suspension parts minimum plus labor or your own effort) the stock 19's are optimal.

after some track experience I realized that even though I was running lightweight 18' oz allegertas with super sticky r-comps, my turn in was greatly compromised and I was sacrificing a lot of potential in lap times.

so get 19' r comps as the car needs a nice stiff sidewall on a thinner tire with stock suspension.

if you achieve a lot of negative camber the "right" way, then 18s and r comps make tons of sense.

if you don't believe me watch best motorings video on the comparison of 18 to 19s on our car. It's out there on the internet. I think this is it: https://www.youtube.com/watch?v=_4pGlX12rjo

8202632

I Iove this forum. Thanks everyone for the great advice!!

Alexandrius

oh also, 19s are not THAT much more pricey than 18s.

On tire rack its $1100 for a set of R888 that will last you YEARS of casual Drivers ed events that you can swap to for driving to/from track and will give awesome grip.

They are basically the same price for 18s version.