WTB Proterra Light i25 Rear Wheel - 700 12 x 142mm Center-Lock Black XDR 28HWTB Proterra Light i25 Rear Wheel 700 12 x 142mm Center Lock Black XDR 28H. Proterra Light i25 wheels are for all you gravel riders out there. Proterra Light i25 wheels feature an open cavity profile to minimize weight and maximize efficiency as you get lost out where the pavement ends. Like all other Proterra wheels the responsive 6 pawl freehub offers 5 degrees of reliable engagement whether youre crushing a gravel ride or have your frame bag