You can use a yellow grease pencil/shoe polish to mark a tread block near the arror which will help you see where the tires are wearing. You can see in the pic where Bill's are wearing. About 1/2-3/4" above the arrow. Measure your tire pressure COLD.
Your 18's will take a bit more pressure than the book states for the 16" Fuchs. This is where the fun begins as I run totally different pressures than Bill's recommendation. I'll run higher pressure in front than the rear.
So follow the procedure above and when you find where the wear indicator is good start experimenting with 1-2lb increments until you like what you feel when the car drives. There is no 'perfect' pressure. Just one that is acceptable in most situations you will encounter.
Enjoy!
-Michael
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Michael
'82 Euro SC 'Track Rat' 22/29 Hollows, 22/22 Tarrets, Full ERPB F/R, Rennline Tri Brace, Glass bumpers, Pro 2000's, 5 pts, blah blah blah
'13 Cayenne GTS