A crane is not a truck with a bigger tyre
The first mistake in a crane TPMS project is treating the crane as a heavy truck. A mobile crane spends most of its life stationary, then moves with a load case that changes axle load dramatically. Tyres are large, pressures are high, and the wheel positions are rarely in a neat 4 or 6 pattern. Some cranes have 8, 10 or more positions across several axles, and the steering axles are often the ones a fitter cannot reach without a pit or a lift.
That shape of vehicle changes the installation plan in three ways. The wheel survey matters more than the hardware. Receiver placement has to be decided before anything is fitted. And the pairing sequence has to be written down, because a crane that is only moved a few times a month is a crane where nobody remembers the procedure six months later.
Step 1: Survey the wheel positions before ordering anything
Walk the crane and record every wheel position with a number, an axle reference, and a note on access. A useful record looks like this:
- Axle 1, left and right, steering
- Axle 2, left and right, drive
- Axle 3 and 4, left and right, drive or tag
- Any additional positions on the carrier or on a trailing bogie
For each position note whether the sensor can be reached from the side, from underneath, or only with the wheel removed. Note the valve type. Note whether the wheel has a band-mounting groove inside the rim. This record becomes the pairing sheet, and the pairing sheet is what prevents the most common field error: pairing sensor number 4 to the wrong wheel.
For a crane, also note which positions are duals. A dual pair looks like two sensors close together, but it is two separate pressures and two separate alarms.
If you want to see what a completed position list looks like before you start, the crane page on our installation index shows the layout we use on site: /installations/mobile-crane.
Step 2: Choose the sensor form for each axle
There are two practical forms. External sensors screw onto the valve in place of the valve cap. Internal sensors are banded to the inside of the rim.
For a crane, the decision usually follows access rather than preference. Positions a fitter can reach easily are good candidates for external sensors, because a valve-mounted sensor can be checked and replaced without removing the wheel. Positions that are hard to reach, or where the valve is exposed to impact on site, are better served by band-mounted internal sensors.
Two practical notes. First, keep the mix under control: a crane with mixed forms is fine, but record which form is on which position, because battery life and replacement procedure differ. Second, never fit an external sensor without confirming the valve itself is sound. A leaking valve under a sensor reads as a sensor fault and wastes a site visit.
The pressure range of the tyre matters too. Crane tyres run at high pressure on the road and can be adjusted for site work. Make sure the sensors you order cover the range you actually use, with headroom, rather than the range printed on the tyre sidewall.
Step 3: Decide receiver placement before fitting sensors
The receiver is the part that decides whether the system works in service. Place it by signal path, not by convenience.
Three rules work well on cranes:
1. Put the receiver high and central. Under the carrier deck, away from the engine bay and away from hydraulic tanks, is usually better than in the cab.
2. Keep the antenna clear of steel. A receiver bolted to a steel panel with the antenna flat against it will lose range.
3. Plan for the longest vehicle configuration. A crane that can be driven with a long boom or a jib has a different radio path than the same crane parked.
If the crane has more than about 10 wheel positions, or has a trailing unit, plan a repeater from the start rather than adding one after commissioning. A repeater is not a fix for a bad receiver position, but it is the correct answer for a genuinely long vehicle.
Step 4: Fit the sensors, one position at a time
Fit in axle order, and record each sensor ID against its position as you go. Do not fit all sensors and then try to identify them by signal strength; on a large crane two positions can be close enough that the wrong reading looks plausible.
For external sensors, clean the valve thread, check for leaks after fitting, and fit the locking nut if the sensor design uses one. For internal sensors, band the sensor so it cannot move under centrifugal load, and confirm the band is tight enough that the sensor does not touch the rim wall.
Record the pressure at fitting. It becomes the baseline for the first week of readings, and it is the fastest way to catch a slow leak that started during installation.
Step 5: Pair with the handheld tool, in the recorded order
Pairing is the step that gets skipped and then blamed later. Pair in the same order as the wheel survey, using a handheld tool, and confirm each position on the tool before moving to the next.
We shot the full pairing sequence on a 4-wheel and a 6-wheel bus, and the procedure on a crane is the same: one handheld tool, one position at a time, no laptop, no app. The video is here if you want to see the procedure being run on an actual vehicle: How we test and pair TPMS sensors on site.
Two things worth writing on the pairing sheet: the date, and the person. Crane TPMS projects fail quietly when nobody knows who did the commissioning.
Step 6: Verify on the display and on the data output
Commissioning is not finished when the tool shows a reading. It is finished when the reading appears where the operator will actually see it, and when the data output is correct.
Check three things:
- Operator view. Every fitted position appears with the right pressure on the display or the vehicle screen.
- Alarm test. Deflate one position by a known amount and confirm the alarm appears where it should, within the time you expect.
- Data output. If the receiver feeds a CAN bus or an RS232/RS485 link, confirm the frames arrive with the correct IDs and the cycle you specified. Our crane installations typically use a receiver with one output interface, chosen at order time, with the CAN variant running at 250 kbps and a 10 ms data cycle.
If the crane has a telematics unit, this is also the moment to confirm that the gateway passes the TPMS data through without dropping frames when the vehicle is stationary for long periods.
The three mistakes that cause callbacks
1. Receiver placed for convenience. The system works at commissioning and drops positions in service when the crane is loaded or the boom is extended.
2. Pairing order not recorded. A wheel is replaced, the sensor is refitted, and now position 7 reports position 9.
3. Valve condition ignored. External sensors get blamed for leaks that started at the valve.
What to ask a supplier before you buy
Ask whether the receiver has a single output interface or several, and which one you are ordering. Ask for the frame list and the cycle time in writing. Ask what happens to the data when the vehicle is parked for a month. Ask whether the pairing tool is included, and whether a replacement sensor can be paired in the field without returning the receiver.
If you are building a crane TPMS project and want the wheel-position sheet, the frame list, or a sample plan for your fleet, send the vehicle type and the number of positions through /contact and we will come back with a layout. For OEM and custom receiver configurations, start here: /oem-odm.