Every SPEEDHUB supplied directly from the Rohloff factory are to date, equipped with a splined sprocket system. This system enables the easy, tool-free replacement of sprockets. Every SPEEDHUB version ever produced can be retrofitted to run this new splined sprocket system as opposed to the original threaded sprockets. All Rohloff splined sprockets (13 - 19 & 21 tooth) are reversible and use a 57mm chainline. These sprockets require the Splined Carrier Adaptor if your hub doesn't have one.