Tire Pressure Again
#1
Senior Member
Thread Starter
Tire Pressure Again
Look at these two Pics. Made three calls to different dealers. Two said whatever is on the gas door. Other said depending on season. On one of my past services from same as gas door dealer I left with pressures 36 and 38 front, 40 and 41 rear. Confused . Non 4matic.
Hd
Hd
#2
Super Member
I, naively, expect Mercedes dealers to set the pressures at manufacturer's specifications. Some will and in this case I would expect the fronts at 31 a nd the rears at 32 assuming average speeds under 100 mph and normal passenger load. Some techs erroneously believe they are doing you a favor in over inflating to the max in an attempt at increasing MPG or their ideas of good handling. Why this happens is beyond me but has happened to me many times.
#3
Junior Member
There are two issues with this TPMS warning. There should be no warning given for an over-inflation of the tires. I suspect that the internal settings of the TPMS are those of the 4-matic (38-39 PSI) and the fuel door label is the staggered spec.
Secondly, for those of us in the north climates, if the servicing is done in the winter, I expect tire inflations to be higher than recommended for two reasons. The service bay is much warmer than the outside temp. Tire pressures drop about one PSI for every 10 degrees fall in temperature. Additionally, in very cold conditions, the valve stems can stick when adding air. So topping off outside has its risks.
Secondly, for those of us in the north climates, if the servicing is done in the winter, I expect tire inflations to be higher than recommended for two reasons. The service bay is much warmer than the outside temp. Tire pressures drop about one PSI for every 10 degrees fall in temperature. Additionally, in very cold conditions, the valve stems can stick when adding air. So topping off outside has its risks.
#4
Senior Member
Thread Starter
mr.b & jfz thanks. So the dealer reset to incorrect settings on previous visit? Are they supposed to add for the +4 psi? Looks like a trip to dealer is in order.
Hd
Hd
#7
Super Member
Natcahd I had the same warnings recently and reset each time as Popo described. Not sure why the warning returned or started in the first place. I am hoping TPMS does not have a glitch emerging.