Combo beam

Also called combination beam, combo pattern, driving/combo, combo lens, combo light bar

A combo beam is one lamp or bar carrying two different optics at once, usually a narrow spot for distance blended with a wider pattern for the near ground, so a single housing covers both jobs without doing either at full strength.

What is a combo beam?

Mixed optics behind one lens. Rather than every reflector in the housing being cut to the same shape, some are cut narrow and some wide, and what leaves the lamp is the two patterns laid over each other. KC HiLiTES puts it in a line: a combo beam combines different optics to create a balance of distance and width, such as with light bars. Baja Designs sells the same idea as Driving/Combo, a lens carrying a 42 degree driving optic and a 9 degree spot optic together, which the company calls maximum trail coverage in a single light.

On a bar the mixing is between separate reflectors rather than inside one lens. KC described its discontinued 30 inch FLEX Array combo bar as angled spot and spread reflectors together, for forward distance and for peripheral light along the road edges. On a pod it happens inside one lens instead, which is why a pod can change from combo to spot by changing a piece of plastic.

Baja Designs treats it as the pattern a lighting package is built around. Its Zone 3 is named driving combo, sits at the centre of the vehicle on the bumper or in the grille, is meant to be noticeably brighter than the near-field zones either side of it, and is where the company says a combo lens belongs, because it combines wide and spot elements in one lens.

What the blend costs

Peak intensity, by a measurable amount. KC's FLEX ERA 4 ships two lenses for the same 7,912 lumen pod, and the maker's own table gives the combo lens 161,000 candela against the spot lens's 180,000. That is about eleven percent more peak intensity, which is under six percent more reach, traded for the width the combo adds. A fair trade for a lamp that has to do both jobs, and a poor one for a lamp bought only to see a long way.

The larger cost is control. Two patterns behind one lens share one switch and one aim. You cannot turn the wide half off when the dust comes up, and you cannot point the narrow half further down the trail than the wide half. Separate pods on separate circuits keep both of those choices, which is the real argument for pods over a combo bar and the reason builds with the space for it run several patterns rather than one blended one.

When a combo is the right answer

When you are fitting one pair of lamps rather than four, when the ground you drive changes pace within a single evening, and when there is one place on the bumper to mount anything at all. Those are the ordinary conditions of most vehicles, which is why combo is the pattern most auxiliary lamps ship in.

It is the wrong answer when the wide half becomes a liability. In dust, fog and falling snow the fix is switching off the lamp lighting the air in front of your eyes, and a combo gives you no way to switch off half a lens.