GTC 18" wheels are 7.5J x 18 ET 41... 235 50 18
5dr J wheels are 8.0J x 18 ET 46... 235 45 18
There is no real determinable difference to be worried about, you would be doing 38.3mph when your speedo reads 37.2mph. Scrub radius is the same.
If the tyres on the GTC wheels were 235 35 18 you would be doing 34.6mph when your speedo reads 37.2. Positive scrub radius (about 13 mm). Scrub radius will be changed by 13 mm, this may affect the car's handling.
Use this tool to compare different wheel/ tyres... http://www.wheel-size.com/calc/?wheel1=2...0mm&sr=0mm
5dr J wheels are 8.0J x 18 ET 46... 235 45 18
There is no real determinable difference to be worried about, you would be doing 38.3mph when your speedo reads 37.2mph. Scrub radius is the same.
If the tyres on the GTC wheels were 235 35 18 you would be doing 34.6mph when your speedo reads 37.2. Positive scrub radius (about 13 mm). Scrub radius will be changed by 13 mm, this may affect the car's handling.
Use this tool to compare different wheel/ tyres... http://www.wheel-size.com/calc/?wheel1=2...0mm&sr=0mm