SD: sintered Off-Road. Good efficiency and stability under all operating conditions. Suitably resistant to wear, even when exposed to water and mud. Less aggressive than the SX, giving more flexible control."
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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...