Having both a GRP lock and tape measure to hand I can tell you that the internal dimensions are 11.5cm wide, 26cm long (21.5 to start of curve).
@Savvy started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
Having both a GRP lock and tape measure to hand I can tell you that the internal dimensions are 11.5cm wide, 26cm long (21.5 to start of curve).