The GB1-R42 fork bridges give your RockShox BoXXer a 42 mm offset. Combined the GB1-R42 with the RockShox BoXXer 26″ retains the original offset of 42 mm. If the GB1-R42 is combined with the RockShox BoXXer 27,5″, which has an original offset of 48 mm, the offset is reduced to 42 mm. The shorter offset will make your bike more track-stable. Driving at faster speeds becomes safer and easier. This is a great advantage on fast trails.