is formed with a disk receiving slot 86 sized to accommodate the disk brake 26 the handgrip 70 is detachable from the mounting unit 76 by a locking mechanism 88 which by means of a key 90 may be locked and firmly attached to the mounting unit 76 by a locking pin 91 or unlocked to remove the handgrip 70 so it can facilitate as a disk brake lock in fig5 c when the handgrip 70 is mounted on the disk brake 26 it is locked in position by same locking mechanism 88 and corresponding locking pin 91 an example of a locking mechanism suitable for that purpose is illustrated with reference to fig8 b and 8c in order to prevent rotational displacement of the hand grip 70 with respect to the handlebar assembly 74 the mounting unit 76 is formed with a hole 79 engageable by the corresponding locking pin 91 of the handgrip so as to ensure correct relative positioning and to prevent said rotational displacement there between according to a particular embodiment the hand grip is an assembly wherein the span of the disk receiving slot is variable between a constricted position when attached to the mounting unit and an expanded position for locking engagement with a disk brake accordingly while attached to the mounting unit 76 the slot 86 is constricted where it is practically not noticeable fig5 a and when it is detached from the mounting unit 76 the slot 86 spontaneously expands fig5 b and 5 c to a size suited for accommodation of the disk brake.