This part of ISO 4209 specifies the designation, dimensions and load ratings of the metric series of tyres primarily intended for trucks and buses. It is applicable to bias-belted, diagonal and radial tyres for trucks and buses, mounted on 5° tapered rims and on 15° tapered (drop-centre) rims. It is also applicable to different concepts and types of tyres and rims; in these cases, however, appropriate rim/section ratios K1, K4, coefficients K2, K3, CR and construction codes have been added to Tables 3, 4 and 5. ISO 4209-2 deals with requirements for rims.