The welding wire size and type determines the drive roll to obtain smooth, consistent wire feeding. There are three common choices: V-knurled, U-groove and V-groove. Pair gas- or self-shielded wires with V-knurled drive rolls. These welding wires are soft due to their tubular design; the teeth on the drive rolls grab the wire and pushes it through the feeder drive. Use U-groove drive rolls for feeding aluminum welding wire. The shape of these drive rolls prevents marring of this soft wire. V-groove drive rolls are the best choice for solid wire. To set the drive roll tension, first release the drive rolls. Slowly increase the tension while feeding the wire into your gloved hand. Continue until the tension is one half-turn past wire slippage. During the process, keep the gun as straight as possible to avoid kinking the cable, which could lead to poor wire feeding. Following some key best practices related to welding wire, drive rolls and shielding gas can help ensure good results in the MIG welding process.