A motorcycle tire pair comprising a front tire and a rear tire, wherein each of the front tire and the rear tire includes a pair of beads (8, 48), a carcass (10, 50) extending on and between a first bead (8, 48) and a second bead (8, 48) out of the pair of beads (8, 48), a band (12, 52) located radially outward of the carcass (10, 50), and a tread (4, 44) located radially outward of the band (12, 52), the carcass (10, 50) includes a large number of carcass cords (24, 64) aligned with each other and each inclined relative to an equator plane (ELf, ELr), the band (12, 52) includes a band cord (28, 68) extending substantially in a circumferential direction, the tread (4, 44) has a tread surface (16, 56) that comes into contact with a road surface, in a meridian cross-section of each of the front tire and the rear tire, a contour line (TLf, TLr) of the tread surface (16, 56) is equally divided into five parts, the five parts are a center part (CLf, CLr) including an equator (Ef, Er), a pair of middle parts (MLf, MLr) connected to the center part (CLf, CLr), and a pair of shoulder parts (SLf, SLr) connected to the middle parts (MLf, MLr), an arc that passes through the equator (Ef, Er) and both ends of the center part (CLf, CLr) is a first arc, an arc that passes through an inner end and an outer end of the middle part (MLf, MLr) and a center thereof is a second arc, an arc that passes through an inner end and an outer end of the shoulder part (SLf, SLr) and a center thereof is a third arc, a ratio (R1f/R1r) of a radius R1f of the first arc of the front tire to a radius R1r of the first arc of the rear tire is a center arc index (Ac), a ratio (R2f/R2r) of a radius R2f of the second arc of the front tire to a radius R2r of the second arc of the rear tire is a middle arc index (Am), a ratio (R3f/R3r) of a radius R3f of the third arc of the front tire to a radius R3r of the third arc of the rear tire is a shoulder arc index (As), characterized in that the middle arc index (Am) is larger than the center arc index (Ac), and the shoulder arc index (As) is larger than the middle arc index (Am). each of the front tire and the rear tire includes a pair of beads (8, 48), a carcass (10, 50) extending on and between a first bead (8, 48) and a second bead (8, 48) out of the pair of beads (8, 48), a band (12, 52) located radially outward of the carcass (10, 50), and a tread (4, 44) located radially outward of the band (12, 52), the carcass (10, 50) includes a large number of carcass cords (24, 64) aligned with each other and each inclined relative to an equator plane (ELf, ELr), the band (12, 52) includes a band cord (28, 68) extending substantially in a circumferential direction, the tread (4, 44) has a tread surface (16, 56) that comes into contact with a road surface, in a meridian cross-section of each of the front tire and the rear tire, a contour line (TLf, TLr) of the tread surface (16, 56) is equally divided into five parts, the five parts are a center part (CLf, CLr) including an equator (Ef, Er), a pair of middle parts (MLf, MLr) connected to the center part (CLf, CLr), and a pair of shoulder parts (SLf, SLr) connected to the middle parts (MLf, MLr), an arc that passes through the equator (Ef, Er) and both ends of the center part (CLf, CLr) is a first arc, an arc that passes through an inner end and an outer end of the middle part (MLf, MLr) and a center thereof is a second arc, an arc that passes through an inner end and an outer end of the shoulder part (SLf, SLr) and a center thereof is a third arc, a ratio (R1f/R1r) of a radius R1f of the first arc of the front tire to a radius R1r of the first arc of the rear tire is a center arc index (Ac), a ratio (R2f/R2r) of a radius R2f of the second arc of the front tire to a radius R2r of the second arc of the rear tire is a middle arc index (Am), a ratio (R3f/R3r) of a radius R3f of the third arc of the front tire to a radius R3r of the third arc of the rear tire is a shoulder arc index (As),