Side Skirt Extensions & Splitters | Any Size | Street Aero

Side skirt extensions, side splitters, rocker extensions. Whatever you call them, they are the piece that finishes the profile of a lowered car, and we cut them to any length from 60 to 86 inches, and 87 on the cross faded, so they fit yours properly instead of approximately. Every set is CNC cut from 6 mm aluminum composite, ships as a complete driver and passenger pair with stainless hardware, and runs from $172.

Front splitters get the attention, but the side profile is what people actually see when your car goes past them. A set of side skirt splitters drops the visual line of the car, ties the front splitter and rear diffuser together into one design, and turns a factory rocker panel into something that looks intentional. We build 144 vehicle-specific side splitter applications, and for anything not on that list we cut custom sets to your exact measurement.

Order any size: custom side skirt splitter sets

If your car is not in our vehicle-specific lineup, or your side skirts have been changed, you can order a set cut to your measurement. Both options fit all makes and models, and both come as a complete pair.

• Custom Straight Faded Side Skirt Splitter Set gives you a clean tapered profile that eases into the bodywork at each end. It is the subtler of the two and the easier one to live with on a daily driver. 23 lengths available.
• Custom Cross Faded Side Skirt Splitter Set uses a sharper angular transition for a more aggressive look. This is the one to pick if the car is already built and you want the side profile to match. 24 sizes available.

Both run from 60 inches to 86 inches (87 on the cross faded), priced from $172 to $289 depending on length and options. Fitment and function are identical between the two styles. The difference is purely the shape of the outer profile, so pick on looks.

How to measure your side skirts

This takes about five minutes and it is the only step that decides whether your set fits. Custom cut sets are made to your number, so measure carefully before you order.

1. Park on level ground. A sloped driveway will throw the reading off. You do not need to lift the car to measure.
2. Find the usable mounting length underneath the side skirt. This is the flat, supported area along the underside of the factory side skirt, running front to rear. It is not the same as the visible length of the bodywork, and it is usually shorter.
3. Start where the skirt becomes flat and supported behind the front wheel arch, and run your tape back to where it stops being flat and supported ahead of the rear wheel arch. Do not include curved sections at either end, and do not include anything the splitter could not be bolted to.
4. Measure both sides. Cars are not always symmetrical, especially if one side has had bodywork. If the two differ, use the shorter measurement.
5. Round down to the nearest available size. If you measure 74.6 inches, order 74. A set slightly shorter than the available surface mounts cleanly. A set that is too long has nowhere to go.

Two things not to do. Do not use your wheelbase, and do not use a measurement you found on a forum for the same car as yours. Trim levels, appearance packages and aftermarket side skirts all change the usable length, and a number that was right for someone else's car is not a substitute for measuring your own.

If your measurement falls between two sizes, or your side skirts are aftermarket, email us at info@streetaero.com with your year, make, model and trim, a clear photo of the full side of the car, and a close photo of the underside mounting area. We will tell you which size to order. Custom cut sets are final sale, so it is worth the message.

Why buy your side splitters from us

We cut every one of these ourselves in Garden Grove, California. Not sourced, not drop-shipped, not a rebadged overseas panel with our sticker on it. That is the reason we can offer 23 and 24 sizes instead of small, medium and large, and it is the reason we can cut a set to your number at all.

• The best value in the category, and we will say it plainly. A complete two-panel set with stainless hardware and fins available, cut to your measurement, starting at $172. Compare that against what a vehicle-specific set costs elsewhere and then check whether theirs includes both sides.
• The highest quality build we know how to produce. 6 mm aluminum composite, CNC cut with a clean machined edge, stainless fasteners because these live in tire spray, and jack stand cutouts designed in rather than drilled as an afterthought.
• The best packaging in the industry. Long flat panels are the hardest thing in aero to ship without damage, so we over-engineered the boxes on purpose. Every set is wrapped and boxed to arrive looking exactly like it did when it left the shop.
• A real person answers your fitment email. Send us photos and a measurement and you get a straight answer from someone who cuts these, usually the same day.

Fins and winglets

Every custom set can be ordered with fins, and this is the one decision you cannot change later. The fin holes are cut at the same time as the panel, so a set ordered without them cannot have winglets added afterward. Pick now if there is any chance you will want them.

• No Fin/Winglets. The clean look. Straight profile, nothing protruding.
• Ankle Biter. 2.5 inches tall by 7 inches long. The subtle option, with a straight angled rise that adds definition without dominating the side profile.
• Ankle Destroyer. 2.77 inches tall by 7 inches long. Slightly taller than the Ankle Biter with a sharper leading angle. Clearly visible, still street friendly.
• Ankle Destroyer XL. 4.75 inches tall by 11.97 inches long, and by a wide margin the largest fin we make. This is the one for a build where the side profile is meant to be the statement.
• Kankle. 2.5 inches tall by 7 inches long, the same footprint as the Ankle Biter but with a swept, rounded profile instead of a hard angle. Pick this one if you want the fin to look like it belongs to the bodywork rather than bolted to it.

Custom engraving is also available at checkout. Engraved sets are final sale, so check your spelling, capitalization and spacing before you submit the order.

What you get

Every side skirt splitter set ships complete:

• Driver and passenger side panels. A set is always both sides. You are not ordering one and buying the other separately.
• Stainless steel mounting hardware. Stainless because these live directly in the spray off your front tires.
• Installation instructions written for the part you actually ordered.
• Jack stand cutouts in the standard design, so you keep access to your lift points after the set is on the car.

Tools you will need: a drill, a screwdriver, a 10 mm wrench, and a properly rated jack with jack stands.

Made from 6 mm aluminum composite

Our side splitters are CNC cut from 6 mm ACM, aluminum composite material. It is a sandwich panel: two aluminum skins bonded either side of a polymer core. It is not solid aluminum, it is not carbon fiber, and it is not ABS plastic, and we are specific about that because the category is full of vague material language.

The reason it suits a part like this is that a side splitter is a long unsupported span sitting inches off the road. A panel's resistance to bending grows very rapidly with thickness, so two stiff skins separated by a light core stay flat across that span far better than a single sheet of the same weight. It also shrugs off road salt, standing water and UV, which matters for a part mounted in the dirtiest airflow on the car.

Already have your car in our lineup?

We build vehicle-specific side splitters for 144 applications, cut around the exact side skirt on that car. If yours is on the list, start there, because a vehicle-specific set removes the measuring step entirely. Jump straight to the most popular:

• Ford: Mustang side skirt splitters / Focus
• Honda and Acura: Civic / Accord
• Nissan and Infiniti: 370Z / 350Z / Q50 / G35 / G37
• Subaru and Toyota: WRX / BRZ / GR86 / Camry
• Chevrolet and Dodge: Camaro / Corvette / Charger

Browse all side splitters, or build the whole car with a full kit that pairs them with a matching front splitter and rear diffuser.

Installation

Side splitters mount by drilling into the underside of the side skirt so the panel is fastened to something that can carry it. That is deliberate. It is why a properly installed set stays on the car through a winter instead of lifting at one end on the highway.

Lift the car on a properly rated jack with stands on level ground, test fit both sides and check the alignment along the full length before you drill anything. On many applications, removing the factory splash guards gives a cleaner result, though this varies by car, so test fit first. Most owners with reasonable mechanical confidence do the job at home in an afternoon, and our instruction manual walks through it step by step.

Frequently asked questions

What is the difference between side splitters and side skirt extensions?

Nothing. They are the same part under different names. You will also see them called side skirt splitters, rocker extensions, rocker panel extensions and side diffusers. All of them describe a panel that mounts under the factory side skirt and extends the lower line of the car outward and downward.

How do I know what size side splitters to order?

Measure the usable flat mounting length under your factory side skirt, front to rear, excluding the curved sections at each end. Measure both sides, use the shorter figure, and round down to the nearest size we offer. The full method is in the measuring section above.

Will the custom sets fit my car?

They are designed for broad compatibility across makes and models, which is why they are sold by length rather than by vehicle. What decides the outcome is your measurement and having a flat, supported mounting surface underneath the skirt. Universal does not mean every length and every configuration works on every car without planning, so if anything about your setup is unusual, send us photos first.

Does the set include both sides?

Yes. Every complete set includes the driver and passenger side panels, stainless steel hardware and instructions. Single side replacement pieces are available separately if you damage one and need to match an existing set.

What is the difference between straight faded and cross faded?

Purely the shape of the outer profile. Straight faded uses a cleaner tapered transition and reads as subtler on the car. Cross faded uses a more angular transition and looks more aggressive. Fitment, material, hardware and installation are identical, so choose on appearance alone.

Do side splitters require drilling?

Yes. They mount by drilling into the underside mounting area so the panel is secured to structure that can actually support it. Test fit both sides and confirm alignment along the full length before drilling anything.

Can I install side splitters at home?

Most owners with a drill, a 10 mm wrench, a properly rated jack and stands, and reasonable mechanical confidence do this at home. We recommend professional installation if you are not comfortable lifting the car or drilling. Work on level ground and use properly rated equipment.

Do they have jack stand cutouts?

Yes, the standard design includes them so you keep access to your lift points for normal service. Confirm their position against your car's lift points during the test fit.

Will they fit aftermarket side skirts?

Often yes, since the custom sets are sold by measured length rather than by vehicle. What matters is whether there is a suitable flat mounting surface underneath. Send us clear photos of the full side and the underside mounting area along with your measurement and we will confirm the right size for your car.

Can I add fins or winglets later?

No. The fin holes are cut when the panel is made, so a set ordered without them cannot take winglets afterward. Choose your fin option at the time of order if there is any chance you will want them.

Will side splitters affect my ground clearance?

They extend along the lower sides rather than the front, so they do not change your approach angle the way a front splitter does. They do sit lower than the factory rocker, so take curbs and lifts with a little more awareness, and check the hardware occasionally.

How do I clean them?

Water, mild automotive soap and a clean microfiber towel. Avoid harsh solvents and abrasive pads. Hand washing is safest for any aftermarket aero, since automatic equipment cannot be guaranteed to clear low mounted parts. Check the fasteners while you are down there and tighten if needed.

Can I return a custom cut set?

Custom cut and custom engraved sets are final sale, which is why we would much rather you email us your measurement before ordering than guess. Eligible non custom side splitters may be returned within 20 days of the tracking delivery date with prior authorization, sealed in their original packaging, uninstalled, unmodified and complete. A restocking fee may apply.

How long until my set ships?

Built inventory items generally ship within 1 to 2 business days after the order is processed, excluding weekends and holidays. Custom cut sets are made to your size and require additional production time. Shipping is free to physical addresses in the 48 contiguous United States.

Order your set

Measure your side skirts, round down to the nearest size, and choose your profile: Straight Faded for the cleaner taper, Cross Faded for the sharper angle. If your car is already in our lineup, the vehicle-specific sets skip the measuring entirely.

Want us to double check your measurement first? Email info@streetaero.com with your year, make, model, trim, your measurement and a photo of the side of the car and we will confirm your size the same day.