Guys, I looked at the door jam and my tire pressure recommendations are 39 for the back and 36 for the front.

The sticker near the gas cap says:

normal load: 33front 35back
max load: 36front 39back (matching the door jam numbers)

I just checked my tires and the fronts were at 42. I reduced them to 40. The rears are also 40. This is probably what the previous owner ran on.

Should I deflate the fronts to 36? Does it matter what tires I'm running on?

Fronts: 245/40R18 97H - Continental Pro Contact GX SSR
Rears: 255/40R18 99H - Continental ContiPro Contact

As you can see, the back tires are fatter (staggered setup).

Please let me know what I should do!

Thanks!

 

I called a few tire shops. They told me to follow the manufacturer's recommendations. So, I deflated the fronts to 36 and the backs to 39.

Here's what I feel when driving the car now:

1) Lighter - doesn't feel as heavy
2) Lower - feels like I'm more low to the ground (makes sense)
3) Bumpy?? Or, it feels like I can feel the ground more now..like tiny pebbles, etc..hmmm

I guess it "feels" different driving the car now as I was driving with overinflated tires for the past 3 weeks.

All good?

 

Measure the tire tread depth across the tire width. The correct pressure is what gives you even wear.


Also, tires from different makers can require different pressure even when they are the same size so you need to monitor the tread wear.

 

the best practice is: FOLLOW VEHICLE MANUFACTURERS RECOMENDATION. They do tire/driving tests and pressure provided is for best and safe vehicle handling. Remember that the tire is an integrated part of the vehicle suspension. Its pressure reflects directly in vehicle handling. The tire manufacturers will provide a range of pressures good for their product but they DO NOT know what is the best for a specific vehicle.

 

Yes, agree. My air pressure is now set to MB recommendations. I'll have to get used to the new "feel" of the car now since I've been driving overinflated for the past 3-4 weeks. Thanks previous owner - ha ha!

 

surprised you noticed much of a change over 4psi. I've only noticed more roughness with higher inflation around 40-42. As you noticed, the 36/39 on door placard is for the max load. The sticker near gas cap on my car gives the same 33/35 for normal load. I split the difference at set them at 34/37.

Most tire places and tire manufacturers will tell you to follow the door placard.