L.93mm Hub - Standard hub that comes with the chassis. (Please note they are now laser etched on hub as L.93 due to the way they are measured but are the exact same hub as L.98 we have always used.)
L.88mm Hub - Used to free up the rear of kart slightly giving more axle flex.
L.78mm Hub - Used to free up the rear of the kart more significantly by giving most axle.