Maxton Design Gloss Black Side Skirt Diffusers for BMW 1 Series F21 3-Door (3dr) Pre-Facelift 2011-2019 | M Sport/M-Power ABS Side Skirt Extensions (Pair) with Fitting Kit

Maxton Design Gloss Black Sill Diffusers for BMW 1 Series F21 3dr Pre‑Facelift

Give your BMW 1 Series F21 3 door hatch a sharper, lower and wider look with these Maxton Design gloss black sill diffusers. Precision made for pre‑facelift models with the M Sport exterior pack, these rocker extensions sit neatly along the factory side sills to add an aggressive OEM plus aesthetic and clean, purposeful side aero. Manufactured from tough automotive ABS, they are built for daily driving on UK roads while delivering premium styling that ties in perfectly with other Maxton aero parts.

Vehicle fitment

Fits only: BMW 1 Series F21 3‑door pre‑facelift with M Sport styling package. Also searched as BMW F21 3dr hatch pre‑LCI with M Performance style exterior.

Why enthusiasts choose this upgrade

• Real Maxton Design side aero for the F21 1 Series 3dr
• Deep gloss black finish for a premium, factory‑plus appearance
• Automotive‑grade ABS for strength, impact resistance and durability
• Visual lowering effect and enhanced side profile for a stronger stance
• Complements M Sport bumpers and other Maxton add‑ons for a cohesive look
• Straightforward bolt‑on fitting with included hardware and instruction guide

What’s in the box

• Left and right sill diffusers side splitters
• Mounting hardware fixings
• Fitting manual

Fitting manual: Download here

Material and finish

Constructed from ABS for the ideal balance of light weight and toughness. Supplied in a high gloss black finish protected by a thin vacuum‑sealed film. Remove the protective film after installation to reveal a pristine, mirror‑like shine.

Tried and trusted by us

We run Maxton side aero on our own builds and our customers consistently praise the fit, finish and transformation in road presence. A simple styling mod that makes a big visual impact without looking overdone.

Fitting and support

Professional fitting is recommended for best alignment and secure mounting. MJ Modifications offers supply and installation at our Warwickshire workshop. To request a fitting quote, email info@mjmodifications.co.uk.

Good to know

• Test fit before drilling or final mounting
• Designed as a styling enhancement for the side sills
• Suitable for pre‑facelift F21 3‑door with the M Sport pack

Popular search terms

BMW F21 side splitters 3 door, BMW 1 Series F21 sill extensions, rocker panel extensions gloss black, side blades for BMW 1er 3dr, BMW F21 M Sport side aero, Maxton side skirts F21 3dr, BMW 1 Series pre‑facelift side splitters, F21 3dr hatch side diffusers, gloss black sill blades UK, BMW 1 Series F21 body kit upgrades, BMW 1 Series rocker extensions, BMW F21 3dr styling parts, BMW 1 Series 2011 2012 2013 2014 2015 2016 2017 2018 2019 side splitters.