Wheel & dust control
Truck tyre wash equipment, sized by the turn of the wheel
A wheel wash can only clean the tread that passes a nozzle. How much of the tread that is depends on how far the wheel turns between the ramps — which makes bay length, not pump size, the number that decides whether mud reaches the road. Here is the arithmetic, and a calculator that turns your wheel diameter into a configuration.
Complete tyre rotations in the longest bay we build, 12 m
Ground a standard 315/80R22.5 truck tyre covers in one full turn
Wash water recycled in a closed loop, every cycle
Splash guards above the drive surface — the highest in the industry
What the equipment is
A truck tyre wash is a drive-through bay at the point vehicles leave a site. The vehicle crosses it at walking pace and does not stop. Banks of nozzles under and beside the deck throw water at the tread, the sidewalls and the undercarriage while the wheel is still turning; everything that comes off falls into a tank below, where the solids settle out and the water goes back to the pump. A fully loaded truck reaches the road clean, and nobody stands at the gate with a hose.
It is a high-volume machine rather than a high-pressure one, and the distinction matters when you compare specifications. Upwards of a hundred stainless nozzles run at a couple of bar apiece off a single large pump: it is the sheer quantity of water shearing across the tread that lifts packed soil out of the grooves. Pressure alone polishes the high points of a tyre and leaves the grooves full — which is where the mud that ends up on the carriageway was hiding.
Everything below is about the one variable that decides how much of the tread gets that treatment.
What is in one
Six parts, and what each is for
Wash bay
The galvanised drive-through deck with its ramps, side grating and splash guards. Its length is what sets the number of tyre rotations, so it is the first thing to specify and the hardest to change later.
Pump and spray system
One large pump feeding nozzle banks aimed at the tread, the sidewalls and the chassis underside. Aimed, not sprayed — the under-chassis bank reaches what no dry control ever does.
Settling tank or dirt trap
Where the solids come out of the water. A plain steel settling tank for material that sinks; a PCET scraper-conveyor trap where it does not, lifting sludge out continuously into a chute.
Oil skimmer
A belt clearing hydrocarbon film off the surface of the settled water, so the recirculated water stays usable and the discharge you are not making stays one you would not mind making.
Coagulant dosing
Where fines will not settle on their own — coal, ash, cement — a dosing set flocculates them so they drop in the time available rather than going back round to the nozzles.
Control system
Vehicle detection, cycle timing and the pump duty. It runs unattended: the vehicle triggers the wash and the cycle ends on its own, which is what makes the control usable at shift change.
The mechanism
Length buys rotations. Rotations are what clean.
A wheel rolling without slipping travels exactly one circumference per turn. A 315/80R22.5 truck tyre is 1,075 mm across, so it covers 3.38 m of ground every time it comes round. Lay that against the three bay lengths we build and the ladder stops being three numbers and becomes a picture.
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A part turn is a missed band
If the tread only comes round nine-tenths of the way, a tenth of the circumference never faced a nozzle. That band is still loaded when the truck reaches the gate.
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Sticky material needs passes, not pressure
Clay in a tread groove does not leave on the first hit. The first pass wets it, the second shears it, the third clears the groove. That is why the answer is a longer bay rather than a bigger pump.
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The wheel decides, not the fleet size
Trucks per hour sizes the tank. The diameter of the wheel is what decides whether a given bay turns it once or twice — and a loader tyre is half as long again as a tipper's.
Why it matters
The tread you miss is the mud on the road
A loaded tyre carries most of its dirt in the grooves, not on the face of the blocks. Grooves hold it, the sidewall carries a film, and the inner faces of a dual wheel collect the worst of it. Only the part of the circumference that has rotated past a nozzle bank gets cleared — the rest leaves with the vehicle and comes off somewhere between your gate and the next junction, which is precisely where an inspector applies the test.
So the honest question to put to any supplier is not how many bar the pump makes. It is how many complete turns of our wheels their bay delivers, and what happens to the material we actually have.
- One turn clears loose material — dry dust, sand, coarse spoil that is sitting on the tread rather than packed into it.
- Two turns are what wet soil and mud after rain need. The first pass wets and loosens; the second takes it off.
- Three turns are for clay, silty clay and cement slurry — cohesive material that has to be worked out of the grooves pass by pass.
- What rotations do not fix: the inner face of a dual wheel and the chassis underside. Those are answered by nozzle placement and an under-chassis bank, which is why bay length is the first question and not the only one.
The arithmetic
Turns per bay, by wheel size
The last three columns are the number of turns each bay gives that tyre. Complete turns are what count, so read the whole number and treat the decimal as headroom: 2.4 is two turns, not two and a half. Outside diameters are typical published figures and vary a little by make and tread depth.
| Tyre size | Outside diameter | One turn of the tread | 4 m bay | 8 m bay | 12 m bay |
|---|---|---|---|---|---|
| 295/80R22.5 | 1045 mm | 3.28 m | 1.2 | 2.4 | 3.7 |
| 315/80R22.5 | 1075 mm | 3.38 m | 1.2 | 2.4 | 3.6 |
| 12.00R20 | 1120 mm | 3.52 m | 1.1 | 2.3 | 3.4 |
| 12.00R24 | 1225 mm | 3.85 m | 1.0 | 2.1 | 3.1 |
| 17.5R25 | 1315 mm | 4.13 m | 1.0 | 1.9 | 2.9 |
| 14.00R25 | 1400 mm | 4.40 m | 0.9 | 1.8 | 2.7 |
| 23.5R25 | 1595 mm | 5.01 m | 0.8 | 1.6 | 2.4 |
| 18.00R33 | 1805 mm | 5.67 m | 0.7 | 1.4 | 2.1 |
Size it
Your wheel, your material, your configuration
Three answers. The first two decide the bay length and the water treatment; the third decides the tank. Everything it prints comes off the same TW610 ladder as the range pages.
How big is the wheel?
Outside diameter of the tyre, not the rim — the figure on a tyre data sheet as overall or outside diameter. If your fleet is mixed, size on the largest wheel that will use the bay.
Common sizes
Your configuration
TW610 40.8 AG
Above ground. The same configuration is TW610 40.8 UG where the tank can be sunk level with the slab.
- One turn of the tread
- 3.38 m
- What this material needs
- 2 turns · 6.8 m
- Wash bay length
- 8 m
- What this bay delivers
- 2 complete · 2.4 turns
- Water treatment
- 40 kl settling tank
Why this one
- Wet soil, loam, mud after rain needs 2 complete turns of the tread under the jets — 6.8 m of bay, before anything else is considered.
- The 8 m bay is the shortest in the range that gives a 1075 mm wheel those turns.
- A 1075 mm tyre covers 3.38 m of ground per turn, so 8 m works out at 2.4 turns, 2 of them complete.
- The solids drop out of still water on their own, so a 40 kl settling tank is enough and the sludge comes out on a schedule.
Indicative, and deliberately conservative. Tank capacity in particular is a starting point rather than an answer: the type of debris decides how long the water has to stand, so light, slow-settling material can need a bigger tank than the same number of trucks carrying rock. Our engineers confirm the sizing against your water quality and settling time before anything is quoted.
Pollution control
What a missed band of tread turns into
Mud that leaves a site on a wheel does not stay mud. It is deposited on the carriageway, dries, and is then ground to dust by every vehicle that passes — which is how a sediment problem at your gate becomes a PM10 problem along a public road, and a slip hazard in the meantime. The first rain washes what is left into the nearest gully, so the same load also arrives at a watercourse as suspended solids.
That is why the control is placed at the exit rather than anywhere else, and why what matters is how much of the tread is actually cleaned. The United States Environmental Protection Agency's own guidance puts sediment removal at "less than 30 percent up to 60 percent for gravel pads and shaker racks" against "75 percent or more" for a properly installed wheel washing rack. That is a federal regulator comparing controls, not a manufacturer.
The whole loop
Where the dirt goes once it leaves the tread
Rotations get the material off the wheel. What happens to it after that is the other half of a pollution control, and it is the half an inspector asks about second.
Off the tread, into the tank
Everything the jets remove falls straight through the deck grating into the tank under the bay. Nothing is washed to one side and left to find a drain, which is the failure mode of a hose and a hardstand.
Solids out of the water
Coarse material drops under gravity in a settling tank. Fines that would otherwise go back to the nozzles are either flocculated with a coagulant or lifted out continuously by a PCET scraper conveyor. Oil film comes off the surface on a skimmer belt.
Water back round, not out
Around 90% of the wash water is recirculated, so the bay is a closed loop with a top-up rather than a discharge. A wash bay draining to stormwater has swapped a tracking offence for a discharge offence, and the discharge one is usually the more serious.
Sludge off site as a record
What settles out has to be removed and disposed of, on a schedule with a paper trail. Several jurisdictions ask for a wheel-wash log specifically — and a control you cannot evidence is, for audit purposes, a control you do not have.
The rest of the range
Where to take this
Wheel and tyre wash equipment
The main range page: portable deck against concrete pit, and how we size either one.
Portable wheel wash systems
The TW610 — a bolt-together deck with its own tank, commissioned in a day and moved with the project. All sixteen configurations, filterable.
Concrete wheel wash equipment
The TW620 — built into the ground at a permanent exit, flush with the road, with settling designed in.
Wheel wash for construction sites
Four questions about the site rather than the wheel — duration, peak hour, material, excavation — and a configuration you can hand to a supplier.
Site-exit rules, market by market
What regulators actually require where you operate, what an inspector looks at, and where a wheel wash is named rather than implied.
Mining vehicle wash equipment
Where the wheels are too big for a drive-through bay and the answer is a wash lane with fixed cannons.
Questions
Common questions about tyre rotations
How many tyre rotations does a wheel wash need?
One complete turn for loose material, two for wet soil and mud, three for clay and cement slurry. In our range that is a 4 m, 8 m and 12 m bay respectively for a standard truck tyre — but the bay length that delivers those turns depends on the wheel. A 4 m bay turns a 1,075 mm tipper tyre once and a 1,400 mm articulated-dump-truck tyre only nine-tenths of a turn, which is not the same machine at all. The calculator on this page works it out for your diameter.
Why does a longer bay clean better than a stronger pump?
Because the limit is coverage, not force. A wheel presents its tread to the nozzles a bit at a time as it rolls, so the length of bay decides how much of the circumference gets treated and how many times. Raising pressure on a bay that is too short cleans the same band harder and leaves the rest untouched — and past a point it drives water past the tread instead of into the grooves. Cohesive material also needs successive passes to come away: wet, shear, clear.
How do I measure my wheel diameter?
Use the outside diameter of the tyre, not the rim — tyre manufacturers publish it as overall or outside diameter on the data sheet for the size. If you do not have it, a tape around the tread divided by 3.14 gives the same figure, and it is the more accurate way of the two because it accounts for wear. Size on the largest wheel that will use the bay, not the average.
Does the number of trucks per hour change the number of rotations?
No. Traffic sizes the water side — tank capacity, settling time, how fast the system recovers between vehicles — and a higher throughput band does come with a longer bay in our ladder, so it can raise the rotations you get. But it never lowers what the material needs. Dirtiness sets the rotations; the truck count sets the tank.
What if my wheels are bigger than a drive-through bay can handle?
It happens on rigid haul trucks: a 2,645 mm wheel covers 8.3 m of ground in a single turn, so even a 12 m bay is barely more than one rotation. At that size the answer is not a longer bay but a wash lane with fixed cannons that treat a stationary or slow-moving vehicle for as long as it takes. We build both, and we will tell you which one your fleet needs.
Do more rotations use more water?
More nozzles are running, so more water passes through the pump — but consumption per vehicle rises far less than the bay length suggests, because roughly 90% of it is recirculated and only the film carried out on the vehicle and the moisture in the sludge leave the loop. The running cost that scales with bay length is electrical, and it is small against the cost of a road-sweeping contract or a notice.
Send us your wheel size and what it is carrying
Tell us the largest wheel that will use the bay, the material, the peak hour at the gate and whether you can excavate. Our engineers come back with a configuration, the rotations it delivers on your wheels, and a price — and will say plainly where a shorter bay would do.
Request information
Wheel wash for your site exit
Tell us about the gate and we will come back with a configuration and a budget. No obligation, and no call centre.