Steve, pls help me understand why the new 325/30/19 R888 is too wide for the OEM rear rim. AFAIK, the rear OEM TT wheel is 19x11.5, nice match for the 325 R888 according to their posted specs.

 

OEM rear is 11 inches wide.
toyos run SUPER wide.. a 13" wide tire on an 11" rim will make the tire look bulgy. it'll look goofy. i did this a while ago with a michelin cup 315 30 18 on an 11" wheel, and the tire looked like it was going to pop. very bulgy. like the tires of a minivan.

look at this pic. this is a 325 30 19 tire on a 12" wheel (oem gt2). this is a cup tire, which runs wide, just like the r888. in fact theyre the exact same width.
you notice how the sidewall sticks out of the rim ? well, imagine even more tire sticking out because youre putting a 13" tire on an 11" wheel. it will look really goofy and will impact the awd because mounting such a wide tire on a narrow wheel will cause the tire to have a slightly larger height.

 

Hmm, according to this widely used source, Porsche Wheel Fitting Chart, the rear wheel on 997 TT is 19x11.5?

 

you CAN fit a NITTO INVO 325 30 19 on the OEM 11" wheel. it runs 11.5 inches wide.

 

Lexart, thats strange. maybe in europe, the 997 wheel is wider , or maybe its a typo ?
our US cars have an 11" width. here's a pic of the back.

 

Yep, the picture pretty much confirms is for me. The rear wheel must be 19x11, indeed a bit too narrow for 325 R888's. They could certainly use 12" wide rim to get the sidewall to look correct. This may change my calculus again as I'm deciding between keeping OEM wheels as track set or having set of 18s build in 18x9 and 18x12 sizes and proper offsets to host a set of Nitto NT01s . . .

 

wish I knew this last year. I got 305/30zr/19 for my track (stock rims). Would the 1.8% increase have to match the front tires though?

 

yup. so you would do a 245 35 19 to match.

 

Steve, any input on offsets with a 12" wheel and 325 tire?

 

42 is perfect.
literally. it will come right to the edge of the fender without rubbing.

 

Steve

What suspension are you running lowered? Camber?

I have et47 12" 325 and wondering if I can manage a 7mm spacer. Going to check it out this weekend either way.

 

Tom im on GMG springs. rear camber is about 1 degree. front is 1.1-1.2.
et40 on a 12" wheel with a 325 (michelin or toyo) is going to be cutting it close, but i think you'll be ok. it will look SIIIICK.

 

Ok cool my rear is at -2 degrees so it should work with the PS2 which are not as wide as PSS or toyo. I'd go with 5mm but I have 7mm spacers and bolts that I use for my track wheels.

What about your fronts on 8.5" wheel with 245's?
My et is 50 so again et43 would be tight with -1.2 degrees camber?

 

fronts you'll be fine Tom. i run a 5mm spacer on my 8.5" wheel, and a 2mm on my 9" wheel.

 

What is your offset on the 8.5 wheel w/o spacer, 245 tire right?