Two digits, two different tests
IP68 is two ratings in one line:
- 6 — dust tight. No dust ingress under test conditions.
- 8 — protected against continuous immersion in water, at a depth and duration agreed between the
maker and the buyer.
The second digit is where the arguments happen, because "8" without a depth and a duration is not a
statement. Our sensors are tested by immersion:
What the test does to the sensor
The sensor goes under water, stays there, and comes out working: pressure and temperature still
reported, no water in the housing. That is what the video shows, and it is the whole claim. The test
is a production check, not a demonstration — a body that fails it does not ship.
Where the IP rating matters on a machine
| Location | What attacks the sensor | Why the rating matters |
|---|---|---|
| Wheel on a port machine | Wash-down, standing water, salt spray | The sensor is the lowest point on a wet machine |
| Mining haul truck | Mud, pressure washing, slurry | High-pressure cleaning is the usual ingress path |
| Forklift in a food or cold store | Wash-down, condensation cycles | Thermal cycling pulls moisture past a poor seal |
| Trailer parked outside | Rain, standing water in the rim | Long dwell times, low airflow |
What IP68 does not cover — three things
1. High-pressure jets. Immersion and a pressure washer are different tests. If a machine is cleaned
with a lance close to the wheel, say so; the fitting and the seal are chosen for it.
2. Chemical attack. Solvents, acids and some cleaning agents attack the seal material without any
water ingress at all.
3. Mechanical damage. A sensor crushed by a bead or hit by debris fails regardless of its rating.
This is one reason the internal version exists.
The internal versus external question, again
An internal sensor sits inside the tyre: it is protected from jets and debris by the tyre itself, and
the rating matters less for cleaning and more for the bead area. An external sensor is exposed on the
valve stem, so the rating does the work. Neither is "better" — the answer follows where the wheel is
and how it is cleaned.
What we will not claim
We will not quote a depth and duration we have not tested, and we will not describe IP68 as
"waterproof forever". It is a rating under defined conditions; a damaged seal is a damaged seal at
any rating.
FAQ
Is IP68 enough for a wheel that is pressure-washed? Ask us with the cleaning method — high-pressure
jets are a different condition from immersion, and we will say what fits rather than let the rating
imply an answer.
Do the receivers carry the same rating? The receiver is IP68 as well; the display is IP65, which is
jet-resistant but not immersion-rated.
Does salt water change anything? It is harsher on the seal and on the housing; if the machine works
in a salt environment, say so at the RFQ.
Is the rating tested on every unit? The sealing test is a production check on the body; the
published immersion test shows the condition it is checked against.