Place the Rohloff HG-Check on each sprocket of the HG-IG cassette block that you want to check.
Sprockets with tooth numbers between 12 and 21 should be measured as follows: place the last link of the measurement chain (2) on the sprocket with the test roller (5) inclining slightly outwards and press it against the measurement chain (Figure I). With the other hand forcefully press the handle (approx. 10kg/22lb) in the drive direction and swing the test roller (5) into the tooth pocket while the measurement chain (1) is under load.
If the test roller (5) moves freely in the tooth pocket (Figure II), your HG-IG sprocket is still working well. This indicates that even a new chain will run well on this used sprocket.
If the test roller (5) hooks on the tip of the tooth or if you need to use some force to move it into the tooth pocket, the sprocket should be replaced.
If the measurement chain (1) slides from the sprocket profile while the handle (6) is under pressure (Fig. III), the amount of wear is excessive. Sprockets with more than 21 teeth are rarely worn out, so they should not cause any problems while in use. Therefore, a check up is normally not necessary. Nevertheless, you can check whether the measurement chain (1) slips off the tooth profile while putting pressure on the grip (6) (Figure III).