RGR NB Small Tupperware ''Ultra'' Aero Sideskirt

$395.00 - $455.00


Have you ever encountered CFD analysis for a Miata side skirt?

Have you ever seen billet aluminum hardware used in one?

Have you ever seen a side skirt designed and validated to work together with a splitter and a diffuser for a Miata?

Now you have.

Ever since we started RGR, one of our goals has been to apply our professional motorsports and automotive aerodynamic experience to create a comprehensive, yet friendly aerodynamics solution for this platform. Now we are one step closer.

The design:

With our Front Splitter and Spats/Wickers, we managed to greatly increase the low-pressure zone at the front of the car. The spats also created a quasi-evacuating effect behind the front tire but flow separation in that area hindered further potential benefits. Just like in the front, wider rear tires are also in the way, creating extra drag.

This meant that even though the front of the car was making downforce when the air reached the middle of the car, it lost its low-pressure properties. Our rear diffuser helped create a second low-pressure zone in the rear, but the issue remained.

The goal was to manage the air exiting the front wheel well and traveling around the car, as well as to deflect air away from the rear tire to not only reduce drag but also create a difference of pressure that would help "seal" the middle of the car.

We worked hard to design and properly locate a front fin, and we also designed an integrated wicker (spat) that benefited greatly, but one of the best features (and one that you will only find here) of our side skirts is our underskirt airfoils.

Each full side skirt gets 2 underskirt airfoils, one helps deflect the air coming from the front tire away from the car while working together with the fin, and the other airfoil deflects air away from the rear tire while working together with the rear wicker (spat).

Every single element of these side skirts has been designed with function in mind.

All these elements resulted in a significant increase in low pressure under the car as shown in picture #4, effectively achieving the goal of "sealing" the middle of the car. This means more downforce all around.

The next step of our aero solutions will be a flat floor that we expect will increase the efficacy of every single one of our aero parts.


Our side skirts are 100% made in the USA. They employ a combination of lightweight powder-coated sheet aluminum, billet aluminum, machined Delrin, and carbon fiber elements. They are designed to be durable yet light.


Our side skirts have been designed to be functional, but easy to install. They attach in the front to the existing front fender lower mounting points, in the middle by a bracket that gets bolted to the pinch welds (thus allowing access to both sides of the bolt to prevent rust creation), and in the rear to the area just in front of the rear tire with the help of the integrated rear wicker (spat). A combination of stainless steel hardware and double-sided tape holds the side skirt in place.

- Underskirt Airfoils are an optional item, available only with the Full variant
- The Base Side Skirts include everything but the underskirt airfoils
- These Side Skirts are made to order, please allow 2 weeks for processing
- Designed to fit NA and NB Miatas
- The Side Skirts are powder-coated black
- Sold as a set of two
- Includes hardware

Instructions are available here: