IP67 vs IP68 for motorcycle lights: what the ratings actually test

Both ratings sound like "waterproof", and neither of them covers the thing most likely to wreck your lights. Here's what the numbers mean and where they stop.

IP stands for Ingress Protection, and the standard is IEC 60529. A light written up as IP67 or IP68 has been through a lab test, which is more than you can say for the ones sold with no rating at all. The problem is that riders read the number as a promise about real life, and it isn't one.

How to read the two digits

The first digit is solids, the second is liquids. An X in either place means that one wasn't tested.

So IP67 and IP68 share the same dust rating. The whole difference is in the water test.

What separates 67 from 68

IP67 is a fixed test: 1 metre, 30 minutes, still water. Every IP67 light passed the same thing.

IP68 isn't fixed. The standard says the conditions have to be more severe than IP67 and that the manufacturer has to state them, so one maker's IP68 might mean 2 metres for an hour and another's might mean 1.5 metres for 30 minutes. That's why a good product page says "IP68, 2 m for 60 minutes" rather than just IP68. If it doesn't say, the rating tells you less than it looks like it does.

Either way, both are immersion tests in clean, still, room temperature water. A bike riding through rain at 100 km/h is a different situation entirely, and so is a pressure washer held 20 cm from the lens.

What neither rating tests

These are the four that actually kill lights, and none of them appear anywhere in the IP code.

• Pressure washing. This is the single most common way a light fails. A jet at close range pushes water past seals that held fine in a 1 metre tank. IP69K is the rating that covers it, and you won't see it on a motorcycle light. Wash your bike with the lights on the machine, from 50 cm away, and not directly into the seam.
• Thermal cycling. The housing heats to 60°C or more in use, then a cold rain shower hits it. That pressure change is what draws moisture past a seal, and it happens every ride.
• Vibration. A light on a crash bar on a single cylinder bike sees a lot of it. Vibration loosens brackets and works connectors loose, and it doesn't take water to do the damage.
• UV and salt. Polycarbonate lenses haze under sun, and road salt in winter eats aluminium and fasteners. Neither is part of the test.

Why lenses fog up anyway

Sealed housings trap air, and trapped air holds moisture. Heat it and cool it and that moisture condenses on the inside of the lens, which is where the fogging comes from. It doesn't mean water got in.

The fix is a breather vent, a small membrane that lets pressure equalise without letting water through. Lights with one still fog when the air is very humid, but they clear within minutes of being switched on. Lights without one fog, stay fogged, and eventually corrode a board.

If a light does fog and doesn't clear, it's worth checking before you bin it. Most of the time it's the vent blocked with dirt or the connector letting moisture in backwards along the cable, and both are quick to put right.

What to check instead

Take the rating as a floor, not a decision. Then look at these.

• Whether there's a breather vent, and where it is. One on the underside of the housing is doing its job.
• Whether the connector is sealed. A light can be IP68 and still let water in through an unsealed plug.
• What the housing is made of. Aluminium moves heat and survives vibration better than plastic.
• Whether the bracket has any damping, or a rubber mount. On a single, this matters as much as the rating.

In our own range the 4-inch pods and the 120W combo are IP68, and the 7000LM fog light pair is IP67. Honestly, for a bike that sits in the rain, that difference is not what will decide how long they last. All three are aluminium and fanless, and removing the fan removes the part that used to fail first.

See the full range in the motorcycle driving lights collection.

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