THEY are a must for all teams and there is little doubt pit stops will play a key role in the outcome of Sunday's Bathurst 1000.

A smooth, efficient stop can give a team a significant advantage. On the other hand, a single mistake can lead to loss of time, position or even penalties.

It can also potentially endanger the safety of drivers, crew and other competitors.

All crews practice for hours in the lead up to the race.

This ensures each of the seven scheduled stops is smooth, fast and safe and gives the team its best chance of winning.

Here is a run down of what each person in the Holden Racing Team (HRT) pit crew must do.

THE car controller is responsible for the entire pit stop directing the car into position in its pit 'box', supervising each crew member and giving the all-important "Go, go, go!" command.

He must also ensure the car leaves the bay safely.

HRT uses a driver change assistant to help the drivers exit and enter the car during the endurance races.

The driver's harness, cool suit, drink bottle, radio and window netting all need to be unfastened and refastened before it is time to go.

THE air jack attendant raises the Commodore off the ground by inserting the air spike into the valve located in the rear window.

Even for a fuel stop, the car must be raised off the ground or the team faces a penalty.

He also refills the driver's drink bottle.

THE refueller inserts the dry-break fuel nozzle into the car while an observer watches on with a fuel extinguisher.

It takes around 23 seconds to fill the 112-litre HRT Commodore's fuel tank with E85 race fuel at a controlled rate.

THE HRT VF Commodore's 18-inch wheels are secured by a single nut and then fastened by a compressed nitrogen-driven rattle gun.

A V8 Supercar's wheels can be changed in less than four seconds, which is less than the time it takes for a website to load.