Renthal Ultralight™ rear chainwheels are manufactured to extremely tight tolerances from  7075 T6 aluminium alloy which is 66% lighter than steel, yet incredibly durable. Their advanced tooth profile, concentricity and accuracy of fit provide maximum power transfer and long-life.
Renthal’s combination of a high strength base material and exceptionally hardwearing surface result in significantly increased chainwheel life over other brands.
All modern Trials bikes GASGAS PRO, BETA, MONTESA 4RT, SHERCO, SCORPA, VERTIGO, TRS have the same 4 bolt fitment. 141U 520