Pinewood Pro Machined Polished and Nickel Plated Speed Axles for Derby Cars - Over Sized Shaft (includes 4 axles) Slightly oversized .91" diameter for a tighter fit in the wheel bore helps reduce wheel wobble Machined, Polished and Nickel Plated mirror finish minimizes friction to give you a super fast axle Under side of axle head is angled to reduce friction on wheel contact area. Less friction means more speed. Machined axles are perfectly straight Machined axles may not be legal in Cub Scout races. Check your rules.