The standard axle on the Matrix 3 Truck is 50mm long, if you want to fit smaller skate style wheels then you need smaller diameter than teh standard 12mm.
For years MBS's customers have asked if it was possible to fit standard size urethane wheels (i.e. longboard / esk8 wheels) onto Matrix trucks. Well, now you finally can with MBS new Matrix III 10mm axles and a set of 6900 bearings (10x22mm). Whether you're looking for the ultimate street carving machine or just wanting to go the extra mile thanks to urethane's lower rolling resistance now you can!
Fits all standard skateboard, longboard, and esk8 wheels (with 22mm bearing holes) using 6900 bearings (10x22mm).
They are sold each and you would need two for a truck. To change them you remove the small grubscrew near the end and then insert an allen key in the end of the axle and unscrew (it is tight to start with). Then screw in the new axle tight and add in the grubscrew again to lock in place.
The axle is suppled with a 16mm spacer and new wheel nut so you can fit straight on there. See the drawing below showing the size difference.