Posted: Tue Feb 21, 2006 8:40 am
There are a million books and websites to explain this, but here goes:
225/50R15
225 = tread width in mm
50 = aspect ratio (the ratio of height to width, in percentage) ie, this tyre has a sidewall 225 x 50% = 112.5mm high
Note that it's not an absolute value, ie, a wide 40-series tyre can be taller than a narrow 60-series one!
R = radial construction (as all road tyres are now)
15 = rim diameter in inches.
OFFSET is the distance between the mounting flange of the wheel and its centreline. Lower offset means the wheels are mounted out wider.
SCRUBBING usually means that the tyre is hitting this guard/fender liner at some point in its movement range.
ROLLING/FLARING is the modification of the guards to prevent scrubbing...
The OEM 15"s are about 6kg I think... In the case of a light car like the MX-5, lighter is always better, as a wheel is unsprung weight, and more of this leads to a really bad ride quality.
I woudn't want to go bigger than 16" or the wheel starts getting too heavy (unless you have megabucks for forged rims)
Those metal discs behind the wheels are the brake rotors. Don't worry about rust on them, they're cast iron and that's what happens. The working surface of them will be polished clean the first time you use the brakes of a day.
225/50R15
225 = tread width in mm
50 = aspect ratio (the ratio of height to width, in percentage) ie, this tyre has a sidewall 225 x 50% = 112.5mm high
Note that it's not an absolute value, ie, a wide 40-series tyre can be taller than a narrow 60-series one!
R = radial construction (as all road tyres are now)
15 = rim diameter in inches.
OFFSET is the distance between the mounting flange of the wheel and its centreline. Lower offset means the wheels are mounted out wider.
SCRUBBING usually means that the tyre is hitting this guard/fender liner at some point in its movement range.
ROLLING/FLARING is the modification of the guards to prevent scrubbing...
The OEM 15"s are about 6kg I think... In the case of a light car like the MX-5, lighter is always better, as a wheel is unsprung weight, and more of this leads to a really bad ride quality.
I woudn't want to go bigger than 16" or the wheel starts getting too heavy (unless you have megabucks for forged rims)
Those metal discs behind the wheels are the brake rotors. Don't worry about rust on them, they're cast iron and that's what happens. The working surface of them will be polished clean the first time you use the brakes of a day.
