Sprint Filter P08 F1-85 Air Filter for Racing – KTM 990 RC R (2026) PM175S F1-85

A flow rate of 15,000 litres per square metre per second belongs to a condition that, on a road-legal motorcycle, lasts a few seconds at a time. Even on the sharpest machine built around this airbox, wide-open throttle high in the rev range is counted in seconds per ride rather than in minutes. For every hour in between, that rate sits idle and something else is doing the work. Which inverts the usual reason people reach for this element.

Key Features

• Sprint Filter's racing medium: dry polyester at 85 µm and 15,000 l/m²/sec
• Coarser than the standard weave by five microns, yet measured higher for retention
• Oil-free at every stage; compressed air is the entire service procedure
• Direct replacement in the series airbox — nothing cut, nothing remapped
• Costs a little over twice what the standard P08 asks for the same housing
• Warranted two years from purchase and made to last the life of the machine

The rate and the hours

An intake filter has most to say when the throttle is wide and the engine is turning hard, and least to say at every other moment. A road-legal sports machine spends its life overwhelmingly in the second category, whatever its owner intends, because that is what public roads permit. So the argument that this element flows three times what the standard one flows is true and mostly irrelevant to how the motorcycle is actually ridden.

The figure working the rest of the time

Retention is the other half, and here the numbers refuse to behave as expected: the racing weave is measured at 95.22 per cent and the standard P08 at 93.13, despite the racing weave being the coarser of the two. Both come from one comparison at a single particle size, and one hundred microns is coarse enough that neither medium struggles with it — so the measurement ranks them without describing the narrow band in which their ratings actually differ. If the PM175S F1-85 is defensible on an RC R, it is defensible on that figure rather than on the flow one. It still will not make a standard machine quicker; nothing dropped into a standard airbox does.

Care and cleaning

Air against the clean face, worked outward until light passes evenly through the weave again. A wash belongs later in the element's life: lukewarm water, a little mild detergent, rinsed until the water comes away clean. Drying happens in moving air and only there, with no heat source involved at any point, and refitting waits until the polyester is dry right through. Sprint Filter's maintenance sheet for this element is in the Downloads tab.

Fitment & Compatibility

The P08 F1-85 for the KTM 990 RC R, model year 2026. Five machines are listed against this code, joined by a housing rather than by an engine, and the RC R is the newest of them. Order by element code and model year; the complete compatibility list is in the Fitment tab.