A road sweeper uses three different brush types, and each wears at a different rate.
The side brush (also called a gutter broom) is the small disc mounted on an arm
that reaches kerbs, corners and around obstacles — it does the most visible work and is
usually the first part replaced. The wafer brush is the stack of individual
segments bolted along a shaft to build the full-width main broom underneath the
machine; because each segment is separate, a worn section can be replaced on its own
instead of buying a complete broom. Above the main broom, a strip brush acts as a
dust skirt, sealing the suction hood so the fan captures fines rather than blowing them
back into the street.

Choosing the right filament matters more than most buyers expect. Polypropylene is the
general-purpose choice: it will not scratch coated or decorative surfaces and it holds
its shape well in wet conditions. Crimped steel wire removes compacted debris and
construction spoil far faster and typically lasts two to three times longer on abrasive
ground, but it can mark soft asphalt and is not suitable where surface appearance
matters. Most municipal fleets settle on a poly/steel combo, which sweeps aggressively
while protecting the surface.

Because brush life depends on sweeping hours, surface abrasiveness and down-pressure,
there is no universal replacement interval. Fleet operators typically inspect side
brushes weekly and replace when filament length falls below roughly two-thirds of the
original, and inspect wafer segments at the same time for loose rings or missing pins.
Replacing at the right moment protects the brush disc and drive motor from the vibration
and imbalance that a worn, unevenly loaded brush produces.