If you own or work on a 1999 Mazda Miata, one of the most common questions is what size the lug nuts are. Knowing the proper lug nut size is crucial for changing a tire or doing any wheel maintenance. In this article, we’ll cover everything you need to know about 99 Miata lug nuts.

The factory lug nuts on a 1999 Miata are 12mm x 1.50. This means they have a 12mm diameter thread with a 1.50mm pitch. Nearly all OEM Mazda Miata lug nuts from 1990-2005 used this same 12×1.50 size.

Aftermarket lug nuts can vary in size, so always check the specifications if you are replacing the stock lugs. Many aftermarket lug nuts meant for Miatas will also be 12×1.50mm. Make sure you get lugs meant for a Miata, as using the wrong size can damage the wheels or cause the lugs to not secure properly.

What Size Socket for 99 Miata Lug Nuts?

To remove or install the factory lug nuts, you’ll need a 17mm socket. A standard 6-point 17mm socket is preferred over a 12-point socket. The 6-point grips the nuts better and is less likely to round them off.

Most lug wrenches that come with Miatas only fit the smaller 12mm auxiliary spare tire nut. So you’ll need a socket wrench, breaker bar, or impact wrench to remove the 17mm wheel lug nuts. For heavy rusty lug nuts, an impact wrench with a 17mm socket makes quick work of removal.

What Tightening Torque for 99 Miata Lug Nuts?

Proper torque specifications are important when installing lug nuts. Torque refers to how tight the lug nut is, measured in foot-pounds or Newton-meters. Under-torqued lugs can loosen over time and cause a wheel to fall off. Over-tightening can damage the threads and make the lugs impossible to remove.

The factory torque spec for 1999 Miata 17mm lug nuts is:

  • Steel wheels – 65-85 ft-lbs (88-115 Nm)
  • Aluminum wheels – 75-90 ft-lbs (102-122 Nm)

Always use a torque wrench when tightening lug nuts. Ratchet or impact wrenches often over-tighten. Tighten the lugs in a star pattern and double-check the torque after 50-100 miles. This ensures even contact and proper torque after the wheel initially seats against the hub.

What size are the lug nuts on a 99 Miata?

Why BONOSS Aftermarket Lug Nuts Are Best for 99 Miata?

When it’s time to replace worn or rusted stock lug nuts, consider upgrading to a set of BONOSS aftermarket 99 Miata lug nuts. Here’s why they are the best choice for a 99 Miata

  • Forged 50BV30 steel for high-strength
  • Special surface finish to resist rust and corrosion
  • Available in OEM size for factory fit and aftermarket wheels
  • Wrenching flats provide maximum grip for installation/removal
  • Perfect upgrade for modified Miatas making more power

BONOSS lug nuts look great and provide superior durability compared to stock. With proper torque, they will help keep your Miata wheels safely secured for the long haul. Their competitive pricing, quality construction, and range of options make BONOSS the top choice for 99 Miata lug nut upgrades.

So if you’ve been wondering “what size are the lug nuts on my 1999 Mazda Miata?” now you have the complete answer. Whether you need to change a flat or are upgrading your wheels, this guide covers the OEM Miata lug nut size, proper sockets, torque values, and why BONOSS makes the best aftermarket replacement nuts. Knowing the correct 12mm x 1.5 nut size and using quality tools and components ensures safe installation. Your Miata’s wheels and lug bolts will thank you!