open to the exterior of the gripping member 34 thus the channel is nominally radial with respect to the bore 42 the gripping member 34 further includes one or more lateral bores 36 which intersect the channel 48 the bores 36 are configured to accommodate bolts 38 and captive nuts 40 the nuts 40 and bolts 38 have a complementary thread so that tightening of the bolts 38 into the nuts 40 urges the walls 48 u2032 of the channel 48 towards each other the cross sectional dimension of the bore 42 is also thereby reduced so that the wall 42 u2032 of the bores 42 is urged more tightly into engagement with the extension portions 32 a 32 b of the second side support limb 26 thus by tightening the bolts 36 into the nuts 40 the first side support limb 26 is secured and retained on the frame 14 in the above described arrangement when the first side support limb 26 has been set at the desired width to accommodate the brake calliper 10 it will be noted that the lower end 30 b remains spaced apart from its corresponding fixing point on the bicycle frame in region 6 therefore in preferred embodiments of the invention one.