How to Measure

How to Properly Measure Lug Nuts for Torque-Tight™ Indicators

Proper measuring techniques are critical to ensure your Torque-Tight™ lug nut indicators fit correctly. The easiest method is to use a high-quality 6-point socket wrench, but there are some important things to keep in mind:

1. Metric vs. Inch Sizes

Always confirm whether your vehicle uses metric or standard (inch) nuts. For example, a 1-5/16” socket may appear to fit a 32 mm nut, but only a true 32 mm socket provides the proper fit. Always choose the smallest socket that fits snugly to avoid measurement errors.

2. Check Multiple Nuts

If wheel nuts have been replaced over time, they may not all be uniform. The ASME B18.2.2 specification for heavy hex nuts allows for a wide variation in the “across the flats” dimension. Be sure to check several nuts across your truck or trailer to confirm consistent sizing.

3. Using Calipers

If you don’t have a socket large enough, use a pair of calipers to measure directly across the flats of the nut, as shown below:

How to measure across the flats of a lug nut for Torque-Tight indicators

Tip: Accurate measurement ensures you order the correct Torque-Tight™ size, preventing loose fitment and maximizing safety during operation.