Custom is a ladder, not a switch
Almost every enquiry opens with the same sentence: we need a custom TPMS system. A factory hears five different projects behind that sentence, and a quotation only means something once both sides agree which one is on the table.
1. Standard hardware, your identity. Receiver and sensors are catalogue parts. What changes is the label, the laser marking, the packaging and the manual.
2. Configuration. Same hardware, but the wheel map, alarm thresholds, units, language and data protocol are set for your machine.
3. Mechanical and interface work. A different housing or bracket, another connector, a longer harness, a display layout that matches your cab.
4. Electronics and firmware. A new board spin, extra inputs, behaviour the standard firmware does not implement.
5. System level. A new RF design, a new sensor format, or a protocol stack outside the supported family.
Most projects that reach production stop on rung two or three. The expensive mistake is asking for rung four before rung two has been written down.
What can actually be changed
On an industrial platform built from sensors, a receiver, repeaters, a display and a gateway, these items are normally open to change:
- Data output. CAN 2.0B, J1939, RS485, RS232, Modbus, PROFINET and UART are supported across the same hardware family, so the interface is a selection rather than a redesign. The CAN bus route and the serial route differ in who owns the polling loop.
- Behaviour. Alarm thresholds, hysteresis, rapid-leak rate, sensor-loss policy, and units in bar, psi or kPa.
- Wheel map. Every sensor identity bound to a wheel position name that matches your axle drawing, not left as a list of serial numbers.
- Sensor variant. External on the valve stem, or internal fixed to the rim with a band. The internal sensor is rated from −40 to +125 °C with a battery life of five to six years; the external CR1632 sensor is rated from −20 to +85 °C and lasts at least two years.
- Housing and connectors. Enclosure, mounting, cable entry, plug type, harness length.
- Display. A large standalone screen, a small display with a bracket, or no screen at all when the data goes straight to a controller.
- Marking and packaging. Laser marking, carton print, inserted documentation, retail or bulk packing.
- Fleet layer. A 4G CAT.1 gateway with GPS for machines that have no controller to connect to.
Write that list down and mark every line as must change, would like, or no opinion. A missing middle column is where quotations go wrong in both directions.
Configuration versus NRE
Two words decide most of the commercial argument.
Configuration is work done with settings rather than hardware: thresholds, wheel maps, units, a protocol already in the family, marking artwork, packaging, a harness length inside an existing range, the language of the manual. It normally lands in the unit price or appears as a small engineering line, and it does not change the product.
NRE, non-recurring engineering, is work that exists only because of your project: tooling for a new housing, a new PCB, a firmware branch, a display interface, a connector that does not exist yet, a protocol stack that must be written instead of selected, or documentation for a market you are the first to enter. Charging for that is legitimate. What matters is the structure around it:
- Is the NRE credited back against volume, and from which quantity?
- Is it a one-off, or a fee on every revision?
- Who owns the tooling and the artwork, and what happens to them if the relationship ends?
- Is it a lump sum, or itemised so you can drop the parts you do not need?
A factory that will not itemise NRE is asking you to buy an unknown.
The five stages from enquiry to mass production
1. Requirement sheet. Not a product name, a description of the machine: wheel count, tire size, cold inflation pressure, ambient range, washdown regime, the controller that will read the data, annual volume and target price.
2. Configuration and quotation. The factory proposes a platform, a sensor variant, a repeater plan and an interface, and separates configuration from NRE on the same page.
3. Samples and evaluation kit. A small quantity of hardware carrying the same firmware and the same protocol documents that production units will use.
4. Pilot build. A staged quantity that goes onto real machines for a full duty cycle. This is where the wheel map and the alarm thresholds are proven; a catalogue cannot prove them.
5. Mass production. Frozen configuration, batch traceability, per-unit identity, functional test and agreed packaging. Our own sensor capacity runs at 30,000 pieces a month, the number that decides whether a pilot can grow into a programme.
Samples and evaluation kits
Ask for:
- Sensors, a receiver, a repeater and a harness in one kit, so a trial does not wait on a second order
- The configuration tool and the protocol documents, DBC file or register map, that production units will use
- A wheel map template, so the trial produces a document you can keep and reuse
- A functional test record for the samples you receive, and written confirmation that sample firmware and production firmware are the same build
Six questions to ask a factory
1. Which lines of my request are configuration, and which ones need NRE?
2. What is the NRE, and is it credited against volume?
3. Who owns the tooling, the artwork and the firmware branch?
4. Is the sample firmware the production firmware?
5. What is the lead time at each stage, and the minimum quantity at each stage?
6. What documentation ships with the goods, and how is market access handled for my country?
The second half of question six is the one buyers skip. Certification and market documentation are handled per market and per project, so raise them in the requirement sheet, not in the shipping week.
How we work
GZVIA develops the sensors, receivers, repeaters, displays and cloud platform in Shenzhen. One platform covers five configuration families: a large standalone display, a small display with a bracket, an integrated module with CAN, RS232 or RS485, a 4G CAT.1 version with GPS and cloud, and a CAN bus DTU gateway for pass-through. A receiver addresses up to 256 wheel positions, pressure accuracy is ±7 kPa, the sensors use Infineon chips and are rated IP68, the display is IP65, the radio runs at 433.92 MHz, and the receiver works from DC 10–30 V.
Send us the machine rather than a part number, and we will come back with a configuration, an itemised NRE position and the documents your controller needs. Start from the TR100 receiver or tell us what you are building.