gerbjones

guys i have a 2000 gs 300 and i took off my stock 16 x 7.5 offset 50 mm rims and put on 17x7 offset 50mm IS 300 wheels. Everything drives great however my original OEM tire calls for 225/55/16 or 215 55 16 but I have 215 45 17 on them since they came with the IS 300 rims. THey look narrower, but I've driven it quite a bit and it handles fine for me. How much off will the speedo and odo be? Also, could I put a new 225 55 17 tire on it or would that fit?

mitsuguy

iTrader: (2)

not only narrower, but shorter too...

the math is simple:

tire width x aspect ratio x 2 /25.4 + rim diameter

so, 215x.45x2/25.4 + 17 = 24.6" pi x diameter = 77.28" circumference

225x.55.2/25.4 +16 = 25.7" 80.74" circumference

4.3% speedo difference, so, at an indicated 70 mph, you are really traveling 67 mph...