Maxton Design Racing Durability 10mm ABS Side Skirt Diffusers with Gloss Flaps - Black - BMW 1 Series F21 M135i M140i M-Pack 3-Door 2011-2019

Rocker Panel Extensions with Gloss Accent Flaps for BMW 1 Series F21 3 Door M135i M140i

Give your F21 hatch a sharper, lower look with these Maxton Design side splitters. Precision cut from tough 10 mm ABS and supplied with high-gloss add-on flaps, they deliver a purposeful street and track aesthetic while keeping that clean OEM plus vibe. We have fitted these on customer cars and our own builds and the fit, finish and durability have been superb. Owners consistently report that the visual drop and wider stance transform the car in minutes.

Why enthusiasts choose these sill extensions

• Robust 10 mm ABS construction for serious toughness and daily-drive resilience
• UV protected and scratch resistant surface that is easy to maintain
• Weatherproof material suitable for all seasons in the UK
• Gloss flaps included for a motorsport-inspired detail and premium contrast
• Factory-like alignment with a performance styling upgrade
• No painting required out of the box
• Arrives sealed with protective film and authenticity labelling
• Material is TUV MATERIALGUTACHTEN certified for quality assurance

Vehicle compatibility

Fits the following only:

• BMW 1 Series F21 3 door hatchback with M Sport styling
• BMW M135i F21 2011 to 2019
• BMW M140i F21 2016 to 2019

What is included

• Pair of Maxton side skirt extensions
• Gloss finish flaps
• Mounting hardware

Finish options

• 10 mm matte black
• 10 mm matte black with red core

If you choose to paint, apply an appropriate primer before colour.

Trusted by us and our customers

We have installed these Maxton Design rocker extensions multiple times and they continue to impress. The alignment, material quality and overall look are spot on, and customer feedback highlights the aggressive stance and tough build.

Fitting service

Professional installation recommended. For expert fitment, book with MJ Modifications in Warwickshire. Request a quote at info@mjmodifications.co.uk.

Certification and authenticity

Manufactured from TUV MATERIALGUTACHTEN certified ABS and supplied with Maxton authenticity verification.

Search-friendly terms

BMW F21 side splitters, BMW 1 Series sill extensions, M Sport side blades, M135i side extensions, M140i side blades, BMW 1 Series 3 door aero kit, F21 rocker extensions, BMW 1 Series ground effects, Maxton Design skirts, Racing Durability series ABS, gloss flap side trims, black side splitters, BMW F21 body styling, OEM plus side skirts, M Performance look side extensions, 2011 2012 2013 2014 2015 2016 2017 2018 2019 BMW 1 Series 3dr, hatchback side splitters, BMW F21 M-Pack styling, performance aero side panels, track style side skirts, UK fitting Warwickshire.