Wheel fasteners
The Porsche Carerra GT’s center nuts are color coded (red for the left side and blue for the right side).
If you look closely, this red nut (on the driver side of the car) is labeled with an arrow for direction to loosen. Each nut is so-marked to avoid confusion between thread directions. This red nut features right-hand threads, requiring counterclockwise rotation to loosen.
are hard plastic and are available to cover both inch and metric sizes) and two thread pitch gauges (one inch and one metric). That’s all you need to quickly and accurately read any wheel bolt or nut without any guesswork. Common wheel fastener thread sizes: 7/16-20 1-20 9/16-18 M12 X 1.25 M12 X 1.5 M12 X 1.75 M14 X 1.5 M14 X 2.0
Head/drive styles
Note the spline-drive design of the alloy nut. This requires the use of a special Porsche nut driver tool.
32
The “head” of a wheel bolt or nut features a specific drive design and appearance approach. The most conventional drive style involves a hex (six-sided) that requires the use of a six-point wrench. However, other styles do exist, although not encountered as often. These include female hex drive “tuner” nuts which feature a relatively small and smooth outer body
diameter (to ft into small-diameter fastener recesses in some wheels), and a female hex drive hole, requiring a male hex bit for service. Yet another drive style is the spline-drive head which features a symmetric pattern of straight-cut external splines instead of hex walls. Splined fasteners require a dedicated female spline socket, available from the maker of the splined fasteners. In terms of appearance, nuts may be either open (the threaded hole runs all the way through the nut) or closed (threads terminate inside the nut). Closed head styles are varied, and include fush tops, raised conical domes, raised fattop domes, extended hex walls (for easier reach and handling and greater wrench contact area) and radiused domes.
Body and thread length All of the wheel nut and wheel bolt styles that we’ve mentioned are available in a wide variety of lengths, in terms of drive area or thread engagement area. Drive
