Truck Tyre Pressure: Correct Values, How to Measure and Mobile Help

Truck tyre pressure decides your braking distance, fuel consumption and tyre lifespan – a deviation of just a few tenths of a bar already changes how the vehicle handles. This article explains what the correct tyre pressure for a truck actually depends on, how to measure it properly, and what to do if a tyre loses pressure or blows out on the motorway. It’s written for drivers and fleet managers of trucks, trailers, semi-trailers and buses from 7.5 tonnes – exactly where wrong tyre pressure on the highway can turn dangerous fast.

Key Points at a Glance

There is no single “correct” tyre pressure for every truck, trailer or bus. The right value depends on axle load, tyre size, load index and payload, and is found in the tyre manufacturer’s inflation table or manufacturer specifications.
Always check tyre pressure when the tyres are cold – ideally before departure or after several hours standing still.
LKWHelp24 helps trucks and commercial vehicles from 7.5 tonnes with tyre blowouts, low pressure and roadside tyre replacement – 24/7 across Germany.
Send your location via WhatsApp to +49 160 575 3826: motorway number, direction of travel, kilometre marker or GPS pin. Response time is usually 30-60 minutes.
Fixed call-out price from €290 during the day. Truck tyres from size R17.5 from €315. Night, Sunday and public holiday call-outs from €429. The fixed price is always quoted before the technician sets off.

Losing pressure or dealing with a blowout right now? Contact LKWHelp24’s mobile truck tyre service directly via WhatsApp – full contact details and the process are further down this article.

Why Truck Tyre Pressure Matters So Much

A heavy articulated truck rests on relatively small rubber contact patches. Tyre pressure determines how that load is distributed. If pressure is too low or too high, the contact patch changes shape, wear becomes uneven, fuel consumption rises, and in the worst case a tyre blowout follows.

Unlike a car, truck tyre pressure is never one fixed number you simply remember. It always depends on the actual axle load, tyre size, load index and whether the tyre is fitted as a single or as a twin (dual) setup. Only the vehicle or tyre manufacturer’s figures are authoritative – found in the vehicle handbook, on the data plate, or in the tyre manufacturer’s inflation table.

What the Correct Tyre Pressure Depends On

Axle load: A more heavily loaded axle generally needs more air pressure than a lightly loaded one.
Tyre size: Different dimensions (e.g. 295/60 R22.5 or 315/70 R22.5) carry different pressure recommendations at the same load.
Load index: Indicates how much load a tyre can carry at a given pressure – different for single and twin fitment.
Payload: A fully loaded trailer needs different pressure than an empty one.
Application: Long-haul, construction site or regional delivery each place different demands on tyres and pressure.
Speed: Sustained high speeds on the motorway increase the load and heat inside the tyre, which the manufacturer’s table also takes into account.

The correct pressure, as stated by the manufacturer, can only be determined from the tyre manufacturer’s inflation table matched to the actual axle load – generic figures from the internet cannot replace that table.

Steer Axle, Drive Axle, Trailers and Buses: Why Pressure Differs

An articulated truck, a bus or a truck-trailer combination can run several different tyre pressures at the same time – on the steer axle, the drive axle and the trailer or semi-trailer axles. That’s normal, not a mistake: each axle carries a different load and often a different tyre size, so each has its own line in the manufacturer’s inflation table.

Steer axle: usually fitted with single tyres. Steering precision, stability and wet grip are the priority here, so pressure must match the maximum front axle load precisely.
Drive axle: often fitted with twin (dual) tyres. Traction and even load sharing between the two tyres of each twin pair matter most.
Trailer and semi-trailer axles: the semi-trailer frequently carries the largest share of the total load, so its tyres often need their own pressure setting, separate from the tractor unit.
Buses and coaches: as commercial vehicles from 7.5 tonnes, buses follow the same principle – the vehicle or tyre manufacturer’s table for the specific axle load and tyre size applies, not a generic “truck” figure.

In a tractor unit paired with a multi-axle trailer, several different correct pressures can apply at the same time. Always check each axle against its own line in the inflation table rather than assuming one pressure fits the whole combination.

Reading the Tyre Sidewall: Size and Load Index

The sidewall of a truck tyre carries the data needed to find the right pressure. Being able to read it quickly at the roadside saves time when something goes wrong.

Size code (e.g. “315/80 R22.5”): the first number is the tread width in millimetres, the second is the aspect ratio (height as a percentage of width), “R” stands for radial construction, and the last number is the rim diameter in inches.
Load index and speed rating (e.g. “154/150 L”): the load index shows the maximum load capacity – one figure for single fitment, one for twin fitment. The letter shows the permitted speed rating. The tyre manufacturer’s inflation table assigns the correct pressure to this load index.
Maximum pressure: the maximum permitted pressure is printed directly on the sidewall and must never be exceeded.

Reading the size and load index off the sidewall, then matching it to the manufacturer’s table, is the only reliable way to find the correct pressure for that specific tyre and axle load.

How to Measure Tyre Pressure Correctly

Pressure rises while driving as the tyre heats up. That’s why tyre pressure is always checked and set cold – a warm tyre shows a higher reading that doesn’t match the target value.

Apply the parking brake and choose a safe, level spot – never measure an unsecured vehicle on the hard shoulder.
Let the vehicle stand for several hours, or drive only a very short distance beforehand.
Use a calibrated pressure gauge.
Remove the valve cap, place the gauge straight onto the valve.
Compare the reading with the manufacturer’s inflation table for the current axle load.
If a correction is needed, add or release air in small steps and recheck in between rather than guessing the correction in one go.
Screw the valve cap back on, and have the cause checked (valve, rim, foreign object) if pressure loss repeats.

Common mistake: letting air out of a warm tyre because the reading looks higher than the target – this almost always leaves the tyre underinflated once it cools down. Alongside the pressure check, always inspect the tyre visually for damage: sidewall cracks, embedded objects or tread deformation. The legal minimum tread depth for truck tyres in Germany is 1.6 mm in the main grooves.

Twin Tyres: Why Both Must Match

Many drive and trailer axles run on twin (dual) tyres – two tyres mounted side by side at one wheel position. This adds an extra check to the routine.

Both tyres of a twin pair should be kept as close as possible to the same pressure. If one is noticeably lower, the other tyre ends up carrying more of the load and can overheat.
A twin tyre that looks fine from the outside can still be running on a seriously underinflated or flat partner – the inner tyre is hard to see and is often the one that gets skipped during a quick visual check.
Continuing to drive on a flat inner twin tyre typically destroys the second tyre and often the rim as well – check both tyres of every twin pair, not just the visible outer one.

What Happens With the Wrong Tyre Pressure

Condition	Typical consequences
Pressure too low	Larger contact patch, more flexing and heat build-up, higher fuel consumption, increased risk of carcass damage and blowouts, longer braking distance
Pressure too high	Smaller contact patch, uneven wear concentrated in the tread centre, worse traction and wet grip, harsher handling

Either way, breakdown risk increases. A truck tyre running well under pressure can blow out on the motorway without warning – exactly the moment fast mobile help matters most.

Temperature, Season and Tyre Pressure

Air expands when warm and contracts when cold, so the measured tyre pressure naturally shifts with outside temperature and season, even without any actual leak. That’s why pressure should be rechecked against the inflation table at the start of autumn and before winter operation. A TPMS (tyre pressure monitoring system) warns of gradual pressure loss but never replaces regular manual checks with a gauge.

Altitude has a similar, smaller effect: a gauge shows relative pressure, so on routes over mountain passes it’s best to set the pressure at the base and simply keep an eye on it during the climb rather than adjusting mid-route.

Tyre Pressure Routine for Fleets and Fleet Managers

Check cold pressure regularly – before each shift or weekly, depending on mileage and duty cycle.
Log readings per vehicle and axle and compare them to the tyre manufacturer’s inflation table.
Take TPMS warnings seriously and verify them manually without delay.
Train drivers to recognise early signs of pressure loss (altered handling, vibration, TPMS alerts).

LKWHelp24 also supports fleet managers and dispatchers beyond their own workshop: when a tyre loses pressure or blows out en route, we organise fast help right at the vehicle’s location through our nationwide network of service partners.

Emergency: Wrong Tyre Pressure or a Blowout on the Motorway

Switch on hazard lights, don’t brake hard, let the vehicle roll to a stop gradually.
Never continue driving on a flat or badly damaged tyre, even for a short distance – it destroys the carcass and the rim and can make an on-site repair impossible.
Pull as far right as possible onto the hard shoulder, a rest area or a car park.
Put on a high-visibility vest, set up the warning triangle (about 150 m on a motorway), exit via the passenger side and wait behind the barrier.
Contact LKWHelp24 via WhatsApp at +49 160 575 3826: share your location (motorway number, direction, kilometre marker or GPS pin), vehicle type and tyre size.
The fixed price is quoted before the technician sets off. Response time is usually 30-60 minutes. If the vehicle can’t be repaired on site, our towing service takes over.

LKWHelp24: Mobile Tyre Service and Breakdown Help for Trucks From 7.5t

LKWHelp24 is a dispatch service for mobile truck tyre service and breakdown assistance for trucks and commercial vehicles from 7.5 tonnes – including trailers, semi-trailers and buses – 24/7 across Germany, through a network of local service partners.

Mobile truck tyre service – tyre replacement and fitting on site, from tyre size R17.5.
Breakdown assistance – help with tyre issues, jump starts and minor technical faults; see our full truck breakdown service for the complete picture.
Towing and recovery – when on-site repair isn’t enough.
Languages: German, English, Polish, Russian – for international drivers passing through Germany.

Service	Price
Daytime call-out	from €290
Truck tyres from R17.5	from €315
Night, Sunday and holiday call-out	from €429

The fixed price is always quoted before the technician sets off – no hidden costs. Contact: WhatsApp/phone +49 160 575 3826 (WhatsApp is our main channel), email info@lkwhelp24.com, website lkwhelp24.com.

FAQ on Truck Tyre Pressure

How often should I check my truck’s tyre pressure?

Regularly, and always cold – many fleets check weekly or before every longer trip. Never ignore a TPMS warning; always verify it with a gauge.

What tyre pressure should my truck tyres have?

There’s no single answer. The correct value is set by the tyre manufacturer’s inflation table and depends on axle load, tyre size, load index and payload. When in doubt, always follow the manufacturer’s figure on the data plate or in the vehicle handbook.

Why must tyre pressure always be measured cold?

Because the air inside the tyre heats up and expands while driving. A warm tyre reads higher than its actual target pressure – releasing air based on that reading leaves the tyre underinflated once it cools.

Do trailers and buses need different tyre pressure than the truck itself?

Yes, often. The tractor unit, the trailer or semi-trailer, and a bus can all carry different axle loads and tyre sizes, so each has its own line in the relevant inflation table. Never assume the pressure that’s correct for the truck automatically applies to the trailer behind it.

What should I do if a truck tyre keeps slowly losing air?

Get the tyre, valve and rim checked by a workshop or a mobile tyre service rather than repeatedly topping it up. A slow leak usually has a specific cause – a nail or screw in the tread, a faulty valve or rim corrosion – and it can turn into a sudden blowout if left unresolved.

What do I do if my truck tyre suddenly loses pressure on the motorway?

Hazard lights on, don’t brake hard, pull over safely to the hard shoulder or a rest area, put on a hi-vis vest and set up the warning triangle, then contact LKWHelp24 via WhatsApp at +49 160 575 3826 with your exact location. Response time is usually 30-60 minutes.

Does a TPMS replace manual tyre pressure checks?

No. A tyre pressure monitoring system warns of pressure loss, but it’s an extra safety layer, not a replacement for regular manual checks with a calibrated gauge.

Whether it’s a pressure problem, a blowout or a roadside tyre change: LKWHelp24 is available 24/7 across Germany for trucks and commercial vehicles from 7.5 tonnes. Message us on WhatsApp at +49 160 575 3826 or email info@lkwhelp24.com.