Disc brake rotor adapter, disc brake rotor including adapter, magnetism generation device

A disc brake rotor comprising:

• a plurality of first coupling portions attachable to a hub of a bicycle with bolts;
• a second coupling portion provided at a position that differs from positions of the first coupling portions;
• a magnetism generation portion;
• and
• an attaching portion that couples the magnetism generation portion to the second coupling portion so that the magnetism generation portion is attachable to and removable from the second coupling portion.

A magnetism generation device attachable to a disc brake rotor including a hub connector configured to be coupled to a bicycle hub, a main body located at a radially outer side of the hub connector, and a plurality of arms extending radially and connecting the hub connector and the main body, the magnetism generation device comprising:

• a magnetism generation portion;
• a holder holding the magnetism generation portion;
• and
• a third coupling portion formed integrally with the holder, the third coupling portion being attachable to a first side surface of the disc brake rotor in an axial direction,
• the holder being configured so that in a state where the third coupling portion is attached to the first side surface, the magnetism generation portion at least partially projecting from the first side surface into a cavity defined between adjacent ones of the arms in a circumferential direction of the disc brake rotor.

A magnetism generation device attached to an adapter main body including an inner portion having a spline configured to be engaged with a spline provided on a bicycle hub, and an outer portion configured to be coupled to a disc brake rotor main body, the outer portion including a projection projecting radially outward, the magnetism generation device comprising:

• a magnetism generation portion;
• and
• an attaching portion attaching the magnetism generation portion to the adapter main body in a manner irrelevant to a fixing function of a fixing member, the fixing member being configured to fix the adapter main body to the hub,
• the attaching portion including a holder holding the magnetism generation portion, and a plurality of engagement portions,
• the holder including a first portion and a second portion that is located at opposite sides of the projection, and
• the plurality of engagement portions being coupled to the first portion and the second portion.