Strange Lightweight Pro Race Spools are forged with Strange designed tooling from premium steel. The forgings are machined on all critical surfaces by computer controlled machining centers and are fully heat-treated. Super lightweight aluminum spools are precision machined and are ideal for applications where reduction of weight is essential. Standard Series steel spools share the same material characteristics as Lightweight Pro Race Spools, without lightening holes. Standard Series steel spools are an affordable and dependable option when weight is not a primary concern. Standard Series aluminum spools are machined from 7075 forged aluminum. The "mass production" of this spool allows Strange to manufacture a quality aluminum spool at an advantageous price. Aluminum spools are ideal for oval track applications where weight is crucial. As with all Strange spools, Standard Series spools are designed to be an easy change over from OEM type units. The internal splines are left in the stock location, allowing for the use of existing stock axles.