Hubcentric wheel spacers Kits. Motorbike MX Tyres. These are precision fit 10mm & 12mm Hubcentric wheel spacers, In this kit you get 4 spacers and 20 extended wheel bolts in Black. These are easy to fit, simply remove your wheel fit the spacers onto the hub (make sure nothing is fowling it onto the hub) and refit the wheel with the longer bolts.