A tyre centre with 4 car bays needs about 750 l/min at 9 bar at the height of the season: the K 75 in its 10 bar version covers it, and the K 110 in 10 bar gives a comfortable margin. Add a truck bay and the need rises to about 1,130 l/min at 10 bar, which makes the K 110 the minimum.
Our compressor for tyre centres page explains why you size for the busiest week. Here is the actual calculation for a 4 bay centre.
The tools at a fitting bay
Typical consumption, to check against your machine manuals:
| Tool | Consumption | Pressure |
|---|---|---|
| 1/2" impact wrench | 300 l/min | 6.3 bar |
| Tyre changer | 150 l/min | 8 bar |
| Blow gun | 150 l/min | 6.3 bar |
| Car tyre inflator | 100 l/min | 6.3 bar |
| 1" impact wrench (trucks) | 600 l/min | 6.3 bar |
| Truck tyre inflator | 150 l/min | 9 bar |
Each fitter only uses one tool at a time, and these tools work in bursts. So for each fitter you count the hungriest tool at 50% of its consumption: the receiver absorbs the peaks.
The calculation for 4 car bays
- One fitter per bay: 4 fitters.
- Hungriest tool: the 1/2" impact wrench, 300 l/min, counted as 150 l/min.
- Need: 4 × 150 = 600 l/min.
- 25% margin: 600 × 1.25 = 750 l/min.
- Pressure: the tyre changer needs 8 bar, plus about 1 bar of losses, so 9 bar at the compressor.
The calculation with a truck bay
- Truck bay fitter: 1" impact wrench, 600 l/min, counted as 300 l/min.
- The 4 car fitters: 4 × 150 = 600 l/min.
- Total: 300 + 600 = 900 l/min, then 900 × 1.25 = 1,125 l/min, about 1,130 l/min.
- Pressure: the truck inflator needs 9 bar, plus 1 bar of losses, so 10 bar.
Which compressor to choose?
| Your centre | Need | Recommended model |
|---|---|---|
| 4 car bays | 750 l/min at 9 bar | K 75 in 10 bar: 0.95 m³/min, 420 L receiver |
| 4 car bays, margin for the season | 750 l/min at 9 bar | K 110 in 10 bar: 1.4 m³/min, 340 L receiver |
| 4 car bays and a truck bay | 1,130 l/min at 10 bar | K 110 in 10 bar: 1.4 m³/min |
| 6 car bays and a truck bay | about 1,500 l/min at 10 bar | K 150 in 10 bar: 2.0 m³/min |
In peak season, jobs follow one another without a break: it is continuous work. A screw compressor is built for that, whereas a piston compressor needs rest time. With the K 75, the 750 l/min need is close to 80% of its flow at 10 bar: it keeps up, but with no reserve if a fifth fitter joins. The K 110 keeps a margin for the busiest days.
On the K series, the refrigerated dryer and filtration are built in: air reaches the wrenches, tyre changers and inflators dry.
Keep the year-round compressor and add a back-up
If a K 75 is enough for the rest of the year, there is no need to buy bigger for a few weeks. A rental screw compressor, from 5.5 to 132 kW, can back it up during the peak and then go back. Ask us about it when you request a quote.
Peak season pitfalls
Servicing at the wrong time. The first service on a K series screw compressor comes at 500 hours, then every 1,500 hours, with a reminder shown on the controller. Check the hour meter before the season: better to service just before the peak than in the middle of it. Our article on screw compressor maintenance intervals sets out the schedule.
Pressure at the furthest bay. The compressor gauge does not tell you what reaches bay 4. Measure pressure at the inlet of the furthest tyre changer, while an impact wrench runs on the next bay.
Impact wrench peaks. Four wrenches starting at the same moment create a short peak. An extra air receiver near the bays, connected to the network, absorbs it. The air receiver size calculator gives an order of magnitude.
Leaks. Hoses and quick couplings take a beating during the season. A leak that goes unnoticed off-season keeps the compressor running for nothing at the peak: check them beforehand.
Enter your bays and tools in the configurator, or describe your centre in a quote request: we will check the calculation for your busiest week.
For your trade: Compressor for tyre centres.