Motorcycle TPMS Installation: Torque, Seals, Pairing A practical fitment guide for motorcycle TPMS: valve-stem and internal sensors, torque and sealing, pairing, wheel-position marking and the errors that leak.

Two mounting styles, two different jobs

Before any tool comes out, decide which kind of system you are fitting, because the two styles have almost nothing in common at the bench.

A valve-stem replacement sensor replaces the existing valve cap and core assembly. The wheel stays on the bike, the tyre stays on the rim, and the job is measured in minutes. This is the style we build, and it is the reason a two-wheeler TPMS can be sold as an accessory rather than a workshop procedure.

An internal sensor is fixed inside the tyre, strapped or bracketed to the rim, with a dedicated valve through the rim. It cannot be unscrewed by a passer-by and it is better protected, but the tyre has to come off, the wheel has to be rebalanced, and every future tyre change becomes a TPMS job.

Everything below applies to the valve-stem style unless stated otherwise. If you are fitting internal sensors, treat the wheel-balance and tyre-removal steps as mandatory rather than optional.

Before the sensor goes on

Three checks, in this order, and they save most of the problems that would otherwise appear later.

Check the valve first. The sensor measures through the valve, so a valve that leaks or a core that is not seated will produce a low reading no matter how good the sensor is. If the existing valve is old, corroded or of unknown age, replace it as part of the fitment rather than fitting a sensor on top of a suspect part.

Check the wheel and rim for damage. A bent rim or a tyre that has been run flat is not a TPMS problem, and no sensor will compensate for it.

Record the pressures before you start, cold, with a gauge you trust. That gives you a baseline to compare the app against afterwards. If the app and your gauge disagree by more than you are comfortable with at that moment, stop and find out why before fitting the second wheel.

Valve-stem replacement, step by step

1. Let the tyre cool. Do not fit sensors immediately after a ride; the pressures you record and the readings you see will be inconsistent with the cold state the alarm logic assumes.
2. Remove the existing valve cap and, where the design calls for it, the valve core, following the sensor manufacturer's instructions. Some designs replace the whole valve assembly, some replace only the cap and core — they are not interchangeable, so read the fitment sheet that came with the sensor rather than assuming.
3. Clean the valve thread. Road grit and old thread sealant cause cross-threading, and a cross-threaded valve is an air leak with a sensor on top.
4. Fit the sensor by hand until it seats, then bring it to the torque the valve or vehicle manufacturer specifies. Do not improvise a torque figure and do not judge it by feel. Over-torque is the single most common cause of a distorted seal and a slow leak; under-torque is the cause of the other kind.
5. Check for leaks at the valve, with soapy water or the leak-detection method your workshop uses, before moving on.
6. Repeat for each wheel, keeping the sensors in the position they are marked for.

Pairing and wheel-position marking

Pairing is where a straightforward job turns into a support call, so get the order right.

Fit the sensors before you pair them, or at least know which sensor is on which wheel. If the sensors are laser-marked by position — L.F, R.F, L.R, R.R — use the marking, and check it rather than trusting a guess. If they are not marked and you are fitting a set of two or four, mark them yourself before they go anywhere near a wheel, because once the wheels are back on the bike there is no way to tell two identical sensors apart.

Then pair them in the app one at a time, in the order the app asks for, and confirm on the app that each position matches the wheel you actually fitted it to. Fit a set out of order and the rear alarm will appear on the front wheel — which is worse than no alarm at all, because the rider will act on it.

One more point worth knowing: on our sensors the CR1632 cell can be replaced without re-pairing, so a battery change does not disturb the pairing you have just set up. Ask the same question of any system you fit, because a sensor that forgets its position on a battery swap turns routine maintenance into a pairing procedure on every wheel.

Torque and sealing: where leaks come from

Almost every leak reported after a TPMS fitment comes from one of four causes, and none of them is the radio.

Cause	What it looks like	Prevention
Sensor over-tightened	Slow leak at the valve, distorted seal	Use the specified torque, not feel
Damaged or dirty valve thread	Leak that reappears after re-tightening	Clean the thread, replace worn valves
Missing or reused seal	Leak from the moment of fitment	New seal, correct orientation
Valve core not seated	Intermittent low reading	Seat and leak-test before pairing

A fifth cause is worth naming because it is not a fitment error at all: fitting on top of a valve that was already leaking. That is why the pre-fitment check comes first.

What to verify after fitment

Do these in order and most warranty conversations never happen.

• Static check. With the bike parked and cold, confirm every wheel reports a pressure that matches your gauge within the tolerance you consider acceptable.
• Movement check. Ride or spin the wheels, then confirm the readings update. A sensor that never changes is not necessarily a good sensor — it may be a lost one.
• Loss-of-signal check. Walk the phone out of range and confirm the app shows the reading as missing or stale rather than freezing the last number. This is the single most informative test of a BLE system, and it takes thirty seconds.
• Alarm check. Where the app allows it, lower a threshold temporarily and confirm the alarm fires and clears. Then put the threshold back.
• Re-torque and leak check after the first ride, particularly if the sensor design uses a compressible seal.

The mistakes that cause callbacks

Fitting without a leak test. Pairing in the wrong order. Over-tightening "to be safe". Fitting sensors to wheels that already had a slow leak. Handing the bike back without showing the owner what the app looks like when a reading is missing. Every one of these is avoidable, and every one of them produces a support call that has nothing to do with the product.

Where we stand

Our sensors are valve-stem replacement units for two-, three- and four-wheel vehicles, BLE 4.1 on 2400–2483.5 MHz, powered by a user-replaceable CR1632 with pairing that survives the swap. They are laser-marked by wheel position as standard, and rated for −20 °C to +80 °C operating and −40 °C to +85 °C storage at 5–95% relative humidity, non-condensing.

We build them in Shenzhen with capacity of 30,000 sensor units a month, more than 10,000 sets a month going into the Chinese two-wheeler aftermarket. Eight in-house test steps run before shipping, including pressure calibration on every unit, water immersion, RF range, protocol verification, powered ageing, battery current, appearance and dimensions, and a full wheel-position system test. Certification is handled per market and per project, and we will confirm the status for your destination in writing.

The sensor specification is on the BPU100 product page, the app side is on the app page, and typical fitments are shown on the motorcycle applications page. If you want the fitment sequence written for a specific vehicle, tell us the model, the wheel count and the market.