I decided to buy a set of wheels and tires for the track. I went with Forgeline and ToyoR888 for the track. There are a lot more tires for 18" than 19". For the front I bought the Toyo R888 255/35-R18 and for the rear Toyo R888 335/30-R18.

I weighted all tires and wheels before installation. In the table below is a summary of the data.

The 19" factory wheels and tires look better and weight less. The factory tires (as many of you already know) are Michelin Pilot Sport Cup (MSPC) 245/35-R19 and 325/30-R19 for the front and rear respectively.

Data and pictures below.

 

looking good!

 

So your track wheel/tire package weights 18lbs more than stock?

 

Good looking wheels. Surprising how much lighter the OE wheel/tire is.

 

The short answer is yes. But it is a combination of tires and wheels. Basically the tires are the main responsible of the weight increased. Please look at the updated table below.

The factory front tires weight 20 lbs, the toyo R888 255/35-18 weight 26 lbs. SIX pounds more per tire for a total of 12 additional pounds in the front.

The factory rear tires weight 28 lbs, the toyo R 888 335/30-18 weight 32 lbs. Four pounds more per tire for a total of 8 pounds more in the back.

In the end, the front and rear tires add 20 (TWENTY) pounds to the package. The Forgeline front wheels weight 23 pounds, exactly the same as the front factory wheels. The Forgeline rear wheel weight 27 pounds, two pound less than the original rear factory wheel.

Conclusion: The tires add 20 pounds, and the wheels save 4 pounds. In the end, the added weight is 16 pounds.

 

First997,

FYI: The front OEM Centerlock wheel (Part # 997.362.157.95) weights 23.1 Lbs, and the rear OEM Centerlock wheel (Part # 997.362.165.90) weighs 29.0 Lbs from other Rennlist/Porsche sources. So the weight stated in your chart for the front seems anomalously low at 19.5 Lbs. In fact many aftermarket monoblock CL wheels (18" or 19") aren't this low either (3-piece units are heavier in general). Perhaps re-check the total weight of one front OEM wheel and tire combination, this maybe the reason for the large discrepency.

Thanks for putting together this info for everyone. Another pro of your set up is the increased contact patch, but as you mention, at the expense of weight.

Cheers!
Doug N.

 

Doug,

You are right! I weighted the front tire+wheel factory package. They weighted 43 pounds. The Michelin pilot sport cup 245/35-19 weights 20 pounds. The calculated weight for the front factory wheel is 23 pounds. It is the same as the value you mentioned. Thanks for the observation. The data was corrected.

 

first997 what size R888's are you running?

BTW, those Forgelines look awesome!

 

mdrums,

Thanks for the comment. The Toyo R888's are the following:

Front tires:
255/35-18

Rear Tires:
335/30-18

 

Friends, help me understand!
+ Based on this analysis, the only upside in going to 18" setup is having a bigger choice in track tires,
- The downside is increased unsprung mass.
Someone, please correct me if I am wrong!
Many thanks,
wurlie

 

That assumes the width measurement is contact patch width as opposed to the widest point on the tire, which would be shoulder. first997, can you confirm?

 

Nizer: you are correct on max width....however, one would hope tread width/contact patch width is increased on the up-with 255/335 sized tires. Especially, at the expense of all that extra tire weight!!!

Wurlie: one does not have to up size from OEM widths, you can stay 235/305 on 997 GT3s or 245/325 on the new RS......this will keep you away from chubby weight gains and save some unspung weight overall.

Cheers!
Doug N.

 

Nizer,
Your assumption is correct.

Wurlie,
We need lighter 18" tires. There is no weight advantages unless you go with very light 18" wheels. The tires are the worst weight you can add because they are far from the center of rotation.

 

Doug, First - many thanks for your replies.
I understand the issue (did before also, but was pretty shocked to be honest).
I will have to find out the different tyre weights to make my decision. Is there a trustworthy source?
Thanks again,
wurlie