[Ian335xd]

I took my 335xd for a fast drive across a familiar fast road and I felt the car didn't feel quite right so the following day I checked my tyre pressures and found the fronts were over inflated by 3 psi and the rears by 5 psi and this has definitely helped the ride and handling.

So I suggest that you all check your pressures as it seems not all dealers do!

[HighlandPete]

Originally Posted by Ian335xd

I took my 335xd for a fast drive across a familiar fast road and I felt the car didn't feel quite right so the following day I checked my tyre pressures and found the fronts were over inflated by 3 psi and the rears by 5 psi and this has definitely helped the ride and handling.

So I suggest that you all check your pressures as it seems not all dealers do!

Over inflated by 3 & 5psi compared to what? I assume you mean the lowest setting pressure on the door plate.

Obviously a good idea to check pressures, but tyre pressure is a range not a fixed pressure. Most BMW models will have a range of about 0.5bar across the load carried and that is about 7.25psi variation when cold.

Many drivers will run with a few extra psi than lowest figure, when driving hard and at speed anyway, and/or for a balanced wear and road feel.

I run my pressures about midway, (from door plate figures) that's about 3.5psi up on the lowest end of the range, also very sensitive to ambient temperature on the setting pressure, even when cold. There can be a couple of psi difference across our typical day, 10C vs. 20C.

HighlandPete

[Ian335xd]

Originally Posted by HighlandPete

Over inflated by 3 & 5psi compared to what? I assume you mean the lowest setting pressure on the door plate.

Obviously a good idea to check pressures, but tyre pressure is a range not a fixed pressure. Most BMW models will have a range of about 0.5bar across the load carried and that is about 7.25psi variation when cold.

Many drivers will run with a few extra psi than lowest figure, when driving hard and at speed anyway, and/or for a balanced wear and road feel.

I run my pressures about midway, (from door plate figures) that's about 3.5psi up on the lowest end of the range, also very sensitive to ambient temperature on the setting pressure, even when cold. There can be a couple of psi difference across our typical day, 10C vs. 20C.

HighlandPete

I agree with what you say but its not up to the dealers to second guess what pressures the driver would like,BMW spend large amounts of time and money decided what pressures should be run but I agree it is a compromise.

My son races in Ginetta Junior so I know how important tyre pressures on performance.

[HighlandPete]

Originally Posted by Ian335xd

I agree with what you say but its not up to the dealers to second guess what pressures the driver would like,BMW spend large amounts of time and money decided what pressures should be run but I agree it is a compromise.

My son races in Ginetta Junior so I know how important tyre pressures on performance.

So how are you gauging the pressures are not within range from BMW?

Are you checking with a recently calibrated pressure gauge, time of day and ambient temperature exactly the same as BMW? And what is the absolute pressure the BMW garage would use?

Just food for thought.

HighlandPete

[Ian335xd]

Originally Posted by HighlandPete

So how are you gauging the pressures are not within range from BMW?

Are you checking with a recently calibrated pressure gauge, time of day and ambient temperature exactly the same as BMW? And what is the absolute pressure the BMW garage would use?

Just food for thought.

HighlandPete

The gauge I use is calibrated each month at each race meeting and it cost £500 and reads to .1 of a PSI so should be accurate and yes the ambient temperature and pressure do make a difference and ideally you should check your pressures daily but most gauges don't measure these very small differences

[gtsussex]

Are you on P Zeros Ian?

[Ian335xd]

Originally Posted by gtsussex

Are you on P Zeros Ian?

No Bridgestones

[zorroone]

Originally Posted by Ian335xd

I took my 335xd for a fast drive across a familiar fast road and I felt the car didn't feel quite right so the following day I checked my tyre pressures and found the fronts were over inflated by 3 psi and the rears by 5 psi and this has definitely helped the ride and handling.

So I suggest that you all check your pressures as it seems not all dealers do!

A previous post recommended 36 psi front and 38 psi rear on 19". Is this correct.