branmin

Never sure what the correct tire pressures should be. Dont speed or carry heavy weights and mostly looking for a smooth ride. Always thought that around 30 cold was for me anyway, the correct pressure, regardless of what one is supposed to do and allowing for about a 4-5 degree increase when the tires are hot. Was told this was wrong

So yesterday tried out pressures all around at 35 done from my garage and noticed that the car computer read out did not agree..they read 38,s all around. My guage is correct. Left it out in the sun all day(Florida heat in the 90's) and when going home they read 41 all around and heated up to 42??

Checking the tires again tomorrow...what should the pressure be for a smooth ride from cold?

Thx.

happyinboca

I run 36 front and 38 back - My ride is mostly highway and after 18k there is still some meat left on the OEM kicks.

California John

The sign behind the gas door says 35 cold front and rear under normal loads and 36 front and 42 rear under heavy loads. And it suggests you subtract 4 psi if you are running under 100 mph. As in all things like this one must experiment to see for oneself. I can't imagine running under a "heavy load" - are we hauling sacks of cement in the passenger side and rear? - so running the same front and rear makes sense. I run mine cold about 34. less pressure is generally a softer ride and more is harder with generally decreased tire wear.

branmin

yep....put mine back to 34's..far more comfortable a ride.

Thx.

branmin

Oh and forgot to say that what has thrown me is for whatever reason the computer read out shows a 3 degree difference?? so at 34, it states 37 from cold?

California John

I have two air pressure gauges that I used to use when I was racing in SCCA. Those gauges pretty will correspond to the tire pressure readings that I see from the car.

Rouquine

I am having trouble with my tire pressure. I live in So Cal. The inside gas cap says 30 in the front, 38 in the back max. I think there is some +/- allowed. I tried to put it to those numbers at a gas station. Perhaps it was not accurate.

The "check tire pressure" message comes up constantly. The numbers fluxuate constantly. The front tires started showing 32 or 33 so I let some air out.

I don't know if I understand the pressure it wants properly or is the sensor out of wack? My car is a 2013 C250 I bought in April 2014 from a dealer.

What tire pressure should I shoot for and should I try to get the numbers while the car is not too hot? I would like to get the pressure correct instead of the message contantly telling me its wrong (like 2 or 3 times during a 25 min drive)

Thank you, Pamela

BigHat

Pamela,
Not an expert on your model car, but wondering if you are resetting the sensor setting after adjusting the tire pressure. For example, when I reset my tire pressure on a BMW, I insure it's a pressure I want the tires to be set at and then I tell the car that is the new "normal." Sorry if this doesn't apply to the C250. Maybe you should post a question in that section of the forum instead of the new SL section.

As a general rule you should set your tire pressures while the tires are cold and that's what MB expects you to do. A small compressor and tire pressure gauge is not a bad thing to keep in the trunk anyway and then you can check and reset pressures at home too. You bleeding pressure from hot tires could easily lead to this back and forth high/low you're experiencing.

Rouquine

Thank you BigHat. I did move my post and someone there told me about needing to reset after I adjust my tire pressure. Still not sure what numbers to shoot for but hopefully I will get help from that other forum.