BMW G 650 Xchallenge Rider's Manual page 114

Front wheel
10
Front wheel design
112
Front-wheel rim size
Front tire designation
Rear wheel
Rear wheel design
Rear-wheel rim size
Rear tire designation
Tire pressures
Tire pressure, front
z
Tire pressure, rear
Spoke wheel
1.60" x 21"
90/90 x 21
Spoke wheel
2.50" x 18"
140/80 x 18
26.1 psi (1.8 bar), Single rider, with cold tire
27.6 psi (1.9 bar), Driver with passenger and/or
load, with cold tire
29 psi (2 bar), Single rider, with cold tire
31.9 psi (2.2 bar), Driver with passenger and/or
load, with cold tire