Sprint Filter P08 Air Filter for Road & Track – Triumph Bonneville Speedmaster (2018–2021) SM225S

The Speedmaster carries two people and their luggage. The Bobber it shares an engine with carries one rider and nothing more. Same 1200 twin, same airbox, same element — and a workload that can differ by a wide margin over the same stretch of road. That matters for a part whose life is measured in the air pulled through it. The interval printed for this platform is one figure covering both extremes: a solo rider on a dry evening road, and a Speedmaster two-up with panniers on a summer route. It is an average, and an average is wrong for everybody in a particular direction. The Sprint Filter SM225S settles it by inspection instead: a dry polyester element you clean and refit, rather than a paper panel you replace on a schedule written for someone else's riding.

Key Features

• A single woven layer of polyester, run completely dry — no oil to dose, wash out or leave behind
• 80 µm filtration at a rated 5,050 l/m²/sec, Sprint Filter's standard for road and track use
• The ø 22 micron figure is the thread of the weave, not the width of the opening between threads
• About double the filtering surface of other performance elements, in the unmodified airbox
• Takes the factory panel's place in the standard airbox — no modification, no remap
• Washable and reusable for the life of the motorcycle, two years of warranty from purchase

Loaded and unloaded are two different machines

Air is drawn in proportion to the work the engine does, not to the distance the wheel covers. Two-up with luggage and a headwind, the throttle sits further open at the same road speed; a long climb is taken at a wide opening and low revs. The moments that feel least fast are the ones moving the most air. Two Speedmasters with matching odometers can therefore hold elements in different condition, and nothing in a parts catalogue can know which of the two is yours.

What a filter can and cannot do

It cannot make a loaded Speedmaster quicker. A drop-in element adds no meaningful power to a homologated 1200 twin, and a description suggesting otherwise is selling something a filter is not. What it offers is an intake restriction that returns to the same low value every time it is cleaned, instead of one that only ever rises between purchases — and a part answering to a condition you can look at, rather than to a mileage figure averaged across riders who load their motorcycles very differently.

Care and cleaning

Normal service for the SM225S is compressed air on the clean side, blown outwards through the media. A season of two-up touring earns the longer version: lukewarm water with a mild detergent, rinsed until the water runs clear, then a full dry in open air, with heat and flame ruled out. It goes back in dry and is never oiled. The maintenance sheet sits in the Downloads tab.

Fitment & Compatibility

Made for the Triumph Bonneville Speedmaster built from 2018 to 2021. The Bobber came first in 2017 and ran to 2021 on the same engine and airbox, so this one element serves both — two machines on this part number. Model years are listed in the Fitment tab.