Hubcentric wheel spacers Kits. Motorbike MX Tyres. These are precision fit 15mm Hubcentric wheel spacers, In this kit you get 4 spacers and 16 extended wheel bolts and 4 Locking 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.