Nitrogen in Tyres
There are several reasons why nitrogen is used, most of which have already been mentioned in other posts
- It is 'dry' therefore expands less with changes in temperature - so as tyre heats up during taxi or during an RTO the change in tyre pressure is lower. This can also be important if operating to/from airfield with very different ambients temps.
- It's inert, so if after an RTO the fuse plugs in the wheels melt to release the pressure before the wheel explodes you are not releasing any oxygen onto already red hot brakes
- The nitrogen molecule is bigger than oxygen and hence the tyre will hold it's pressure better/longer thus reducing maintenance
- Nitrogen also does not attack/degrade the membrane on the inside of the rubber tyre - the rubber is porous and the membrane makes it airtight.
Using nitrogen in car tyres is a good thing - it means you can increase cold inflation pressures and still get the same optimum hot inflation pressures. It means that the car will use less fuel on short journeys when tyres are cold as the higher inflation pressure reduces rolling resistance and for those with sports cars it means the car will handle better until the tyres warm up. The smae can be acheived with 'dry' air if you can get it.