Pneumatic tire having a rim interfacing bead profile for improved fit

A pneumatic tire, whose nominal tire width in the tire size designation is in the range of 135 to 275 millimeters, for mounting on a rim comprising

• a pair of axially spaced bead portions, each of said pair of bead portions having, in cross section including the tire axis, a bead profile, said bead profile interfacing with the rim,
• a tread portion with axial edges, and
• a pair of sidewall portions extending from the tread edges to the bead portions,
• said bead profile including a curved line being within a range between a locus of
• Y=f(x)+1 mm
• and a locus of
• y=f(x)-1 mm
• which are made when x-=value is varied from -15.29 to 0.523 mm, wherein ##EQU5## f(x) is a function of x, x is a variable indicating a relative radial distance in millimeter based on a reference point, said reference point being set at the heel point of each said bead portion, defining the direction of increase of the x-value as being radially inward of the tire, and
• y is a variable indicating a relative axial distance in millimeter based on said reference point, defining the direction of increase of the y-value as being axially inward of the tire, wherein
• the heel point is an intersecting point between the straight bead bottom line being inclined at five degrees to the tire axial direction and the straight bead side line being parallel to the tire radial direction.