The science behind convex curvature, when it's worth the extra cost, and the brand-by-brand fitment quirks you should know before ordering.
A blind-spot mirror isn't a gimmick. UK Highway Code-recognised — and on commercial vehicles over 3.5t, legally required since 2009.
Why the wider field-of-view matters
A flat mirror gives you about 14° of viewing arc. A standard convex mirror gives you 22°. A purpose-cut blind-spot insert gives you 38° — enough to put the rear of a typical hatchback in view when it sits in your van's traditional blind spot.
The trade-off
The wider the arc, the smaller objects appear. Drivers used to flat mirrors often misjudge closing speed for the first week.
When to fit one
- Towing — your trailer hides the lane next to it
- Commercial vehicles with high sides (Berlingo Crew Van, Combo, Partner)
- Anything with a B-pillar so wide you can lose a hatchback in it
