Wheels/Tires - Nitrogen Usage Recommendations

Wheels/Tires - Nitrogen Usage Recommendations
Date: May 2008
Order No.: S-B-40.10/60
Supersedes:
Group: 40
SUBJECT:
MY-All, Models All
Nitrogen Use in Tire Inflation
Original equipment and approved replacement tires for Mercedes-Benz passenger cars and light trucks are designed to be inflated with ordinary
compressed air, which generally contains approximately 80% nitrogen. Inflation with ordinary compressed air provides the expected operating
performance for these tires so long as the operator regularly checks and maintains the air pressures as recommended by Mercedes-Benz on the
vehicle's fuel filler door or the driver-side B-pillar.
In normal vehicle use, nitrogen offers negligible benefits and is rarely cost effective. Although, the physical properties of nitrogen can reduce
inflation pressure losses due to the permeability of tire materials and thus, improve the damping behavior; the existence of several other possible
sources of leaks, such as tire/rim interface, valve, or rim/valve interface can significantly limit the effectiveness of nitrogen in maintaining tire
pressure in ordinary vehicle use.
In summary, all tires approved for use on Mercedes-Benz passenger vehicles are designed to deliver their expected performance when inflated with

ordinary compressed air. Mercedes-Benz does not require or recommend the use of nitrogen as the results and benefits derived from its use are not in

Wheels/Tires - Nitrogen Usage Recommendations

Wheels/Tires - Nitrogen Usage Recommendations

SI M 36 01 06

Wheels and Tires

April 2006

Technical Service

MODEL

All

SUBJECT

Nitrogen Inflated Tires

SITUATION

Many customers have inquired about the use of Nitrogen, instead of air, to inflate tires on their MINI vehicles. Please review the information below

to help answer some of the customer's inquiries.

INFORMATION

^ Nitrogen, an inert gas, is nothing more than dry air with the Oxygen removed. The majority of "air" already consists of Nitrogen (78% by

volume). The other elements of air by volume are 21% Oxygen and 1% other gases.

^ All MINI approved tires have been designed and tested to deliver their expected performance when inflated with "air" and the correct tire

inflation pressure is maintained on a regular basis.

^ The use of Nitrogen to inflate tires is not recommended for normal use of MINI vehicles; however, the use of Nitrogen is also not prohibited.

^ There are certain applications where Nitrogen inflation is advisable, i.e. in abnormal environment where wheel and tire overheating may occur

such as in aircrafts, space shuttles, military vehicles, off-road trucks, and race cars. In these applications, the non-flammable Nitrogen can reduce

the risk of fire, because Nitrogen does not support combustion and does not add fuel to the fire.

^ The physical properties of Nitrogen may reduce the inflation pressure loss only from the tire material natural permeability (diffusion through

rubber). However, similar to air, Nitrogen can still escape from other sources of inflation pressure loss such as from wheel, wheel/tire interface,

valve, and valve/wheel interface.

^ The most important thing for the customers is to maintain the correct tire inflation pressure on a regular basis as recommended in the Owner's

Manual. Under inflated tires can reduce road holding, increase hydroplaning risk, increase road hazards sensitivity, reduce tire life, increase fuel

consumption, etc.

^ If equipped on the vehicle, always reinitialize the Flat Tire Monitor (FTM) after the tire inflation pressure has been corrected.