M35 Sports tire pressure

[johninm]

Hi,

I have a M35 Sports for about 2 months now. I need help in setting the correct tire pressure. Mine has 19in high performance bridgestones.

My onboard pressure gauge show me around 29PSI in cold when I start in the morning and it goes to 31 or 32 after getting to normal temperature.It looks low to me. Can some advise ?

How much it should be in cold/normal states ?

[exbmwdude]

You're about ready to get acquainted with the TPMS system. Another PSI lower and it will alert you. I run 33 PSI in mine cold, and they get up to 35/36 when warm.

Might want to take a glance at the owner's manual....

exbmwdude2006 M35S

[szh]

Hi,

I have a M35 Sports for about 2 months now. I need help in setting the correct tire pressure. Mine has 19in high performance bridgestones.

My onboard pressure gauge show me around 29PSI in cold when I start in the morning and it goes to 31 or 32 after getting to normal temperature.It looks low to me. Can some advise ?

How much it should be in cold/normal states ?

That is too low a pressure to run. You should have at least 33 psi (cold measure). I prefer higher ... at 36psi. Tires usually drop pressure steadily as the weeks go by - even without weather changes - so I prefer to run a little bit higher than normal, so that the normal drop still does not take it too low! I check every two to three weeks and it is usually down about 1 or 2 psi at that time.

As always: remember that tire pressure should be measured cold, early in the morning, in the garage, before even the sun has a chance to warm up the tires!

Z

[telcoman]

Hi,

I have a M35 Sports for about 2 months now. I need help in setting the correct tire pressure. Mine has 19in high performance bridgestones.

My onboard pressure gauge show me around 29PSI in cold when I start in the morning and it goes to 31 or 32 after getting to normal temperature.It looks low to me. Can some advise ?

How much it should be in cold/normal states ?

Buy yourself a good quality dial type pressure gauge & put in 35 or 36lbs when tires are cold.

Telcoman

[johninm]

Dont you think 36 will be a little high, at normal it will go to 39 and I read somewhere dont put more than 40 ?

[szh]

Dont you think 36 will be a little high, at normal it will go to 39 and I read somewhere dont put more than 40 ?

Nope, 36 psi will not be too high. Most modern, high-performance tires are rated at 51psi max pressure nowadays. Tire load indexes are measured at 36psi, by the way. There is reason to believe that the "correct" pressure to use is at 80 to 85% of the max pressure value ... this means that some people even run the "51psi MAX" tires at 40 to 44psi. IMHO, this is too harsh a ride, but not unsafe.

So, running at 36psi will give you a very slightly harsher ride than running at 33psi (mostly imperceptible on today's roads) and give you the safety margin that it better. Running at 40psi will be higher harshness (it will become perceptible for sure) and may also wear the tires more in the center than in the outer section of the tread.

But running at 33psi just leaves no margin for error (in the measurement, in the gauge accuracy, the drop over time, etc.).

As a final BTW, when you run at high speeds, it is a requirement that you increase the tire pressure to reduce the sidewall flex (prevents heating and tire failure). In Europe, cars that run on the autobahn are required by the manufacturers to be set to at 7 to 8 psi more tire pressure than "normal" for this reason.

Hope this discussion helps!

Z

[johninm]

Thanks guys.