This is a set of 3 replacement long life tempered steel clutch springs for the UR Compak clutch system. These are optional springs that you can use to fine tune the way the clutch engages by using different tension clutch springs. The bigger the spring, the stiffer it is and the later in the RPM range the clutch will engage. The smaller the spring, the softer it is and the earlier in the RPM range the clutch will engage.
Available in 6 different spring hardness:
B8.5: 0.85mm springs for very slippery tracks.
B9: 0.9mm for slippery track.
B9.5: 0.95mm for grippy tracks.
B10: 1.0mm. for very grippy tracks.
B11: 1.1mm for very high traction or muddy conditions.
B12: 1.2mm for Rally Game class.