BenzWorld Senior Member
Date registered: Jun 2011
Vehicle: 1999 E320 Sedan
Location: SF Bay Area
Mentioned: 0 Post(s)
Quoted: 45 Post(s)
It is noteworthy that MB's recommended tire pressures for one and the same model vary somewhat from country to country, and in the US they are typically lower than in Europe. For my car the US recommendations are 27/27 PSI (Front/Rear) for normal load, the German recommendations for the same model are 32/35 PSI for normal load (these values are for the same wheel/tire size). This is, of course, because in the US cars are not supposed to travel at high speeds, and are often equipped with tires with lower speed ratings. I run pressures closer to the German recommendations.
If you exceed the MB recommended tire pressure somewhat, you won't necessarily reduce tire life in the way in which Check Codes described it. Depending on your tire wear pattern, increasing pressure on the center patch might even be desirable, namely if your tires are wearing out on the sides first. But if you increase it only by some PSI, contact pressure might still remain pretty even across the tire profile. At any event, an increase in tire pressure means reducing the flexing work that the sidewall of the tire has to perform. This means that the tire will remain cooler while driving and will be less likely to develop sidewall cracks (this might only matter if you run tires with long tread life, like most Michelins or Continentals). Because of this, a moderate increase in tire pressure can actually extend the life of the tire. And of course it will save some fuel.
On the other hand, if you increase the tire pressure a lot, the ride will not only become harsher, but you will also put more stress on suspension components (shocks and bushings). These are, of course, designed to absorb shocks, but making them work harder will somewhat affect their life expectancy, just like driving on bumpier roads would.
Last edited by Simon_E; 05-26-2015 at 06:49 PM.
Reason: Clarified the reference to Check Code's post, hopefully to his satisfaction.