>>The replaced rubber weighs more than the gained aluminium. Same OD and
LESS
unsprung weight.
I somehow doubt that.
Check the numbers:
My car stock: (phonedial weight from memory and probably a generous
approximation).
S-03 Pole Position - 22lbs 205/50-15 + ~23lbs Milano Phonedial wheels =
45lbs unsprung.
Khumo ECSTA 712 - 20lbs 205/50-15 + ~23lbs Milano Phonedial wheels =
43lbs unsprung.
My car now:
S-03 Pole Position - 25lbs 225/45-17 + 17lbs Team Dynamics DTM wheel =
42lbs unsprung.
S-03 Pole Position - 21lbs 215/40-17 + 17Lbs Team Dynamics DTM Wheel =
38lbs Unsprung.
And from Mike Nakamura's very informative posting:
6 X 15 Phone dial from 91 Spider = 23 pounds.
6.5 X 14 Montreal Turbina = 12.8 pounds (Campangolo)
7 X 17 HRE 526 that I put on Montreal = 19 pounds (will fit Spiders)
Phone dial with 195/60 P6 tires (used) = 41.5 pounds
Phone dial with 205/55 ZR 15 P7000 tires (new) = 42 pounds
Montreal Turbina with 205/60 VR 14 P600 (almost new, less than 3,500
miles) = 34 pounds
HRE 526 with Bridgestone Pole Position SO-2 (new) = 42 pounds
195/60 P6 = 18.5 pounds (used)
205/60 VR 15 P6000 Sport Veloce = 23 pounds (new)
205/60 VR 14 P600 = 21 pounds (almost new, less than 3,500 miles)
205/55 ZR 15 P7000 = 19 pounds (new)
205/50 VR 15 P700Z = 20 pounds (new)
215/40 ZR 17 Pole Position SO-2 = 23 pounds (new)
In most of these cases, the larger wheels and smaller tires weigh less that
their
stock or near stock counterparts.
-Peter
Stock wheels might just be heavy. My statement assumed similar
wheels in two different sizes. The data above just indicates that
expensive aftermarket wheels are lighter than Alfa's phonedial alloys.