Bicycle wheel rim

A bicycle wheel rim comprising:

• spaced left and right annular tire retaining walls adapted for retaining a bicycle tire therebetween, each of said tire retaining walls having a central axis, a radial inner edge proximate to the central axis, a radial outer edge distal to the central axis, and a brake pad contacting surface opposite to the other one of said tire retaining walls;
• and
• an annular spoke mounting wall interconnecting said radial inner edges of said tire retaining walls;
• said brake pad contacting surface of at least one of said tire retaining walls being formed with a plurality of radial grooves which are spaced apart from each other in a circumferential direction relative to the central axis and which extend along radial directions of said at least one of said tire retaining walls from said radial inner edge to said radial outer edge, each of said radial grooves having at least two opposite open ends formed respectively through said radial inner and radial outer edges of said at least one of said tire retaining walls, wherein each of said radial grooves includes a first groove portion which extends along a second curved line, the second curved line curving in a direction opposite to that of the first curved line and intersecting the first curved line at two points.