NickG

Well I figure if they're going to charge $2500 for pre-delivery they'd better darn well get it right! Checked the tyre pressures on my new 8 the day after I bought it. By my Michelin guage, the cold tyre inflation pressure was 42psi all round. Drove it to the service station 2km down the road and got 41-43psi.
No wonder the thing was twitchy and riding awfully.
If not borderline dangerous, these pressures are at least seriously inappropriate on a brand new car, prepped according to the handbook.

This is the third time in a row I have bought a new car with pressures set way above or below manufacturer's recommendations. (Different brands in every case). Makes you wonder what these guys do to earn their "pre-delivery" $$$ doesn't it?

...and yes I am making a big deal about this with the dealer service dept!

timbo

… wait till you discover they have overfilled you at the first oil change … AND charged you for 4.5 litres of oil, when the sump capacity with filter change is 3.5 litres !!

AMG

Nick, manufacturer recommended tyre pressures are usually low to make the drive comfortable. For performance driving the should be set between 40-42psi. In summer I have mine at 40 and winter 42psi.

Modern cars are compromised for comfort rather than safety IMHO!

Hymee

iTrader: (1)

When you do the Murcott course they will repeat what AMG said. Your pressures are about right IMHO.

Cheers,
Hymee.

AMG

thats reassuring to know that what I have always practiced is what is also taught.

Guess years of being involved in motorsport has taught me well

takahashi

My lazy *** still said 39 psi is the best - otherwise my guts will fall out!

I pump my Camry to 40psi for highway driving ... people look at me if I was an idoit!

Hymee

iTrader: (1)

I wouldn't car how people look at me. I would car how the wear on the tyres looks. At placard pressure, I bet the middle of the tread won't have worn as much as the outside, and I bet if you looked a wheel up (OK - ABS, yeah, yeah,yeah) there would be 2 parallel lines. (I.e. the middle of the tyre is not making proper contact).

AMG

But then again,how many people stand close enough to see the pressure reading on the compressor???????????

NickG

Thanks for the insight guys. The 8 is actually the only car I have owned where the manufacturer's tire pressure recommendations are anywhere near appropriate. My 325i was supposed to be run at 29 front and 31 rear! With that car I settled on 36 all round which gave near perfectly even wear and good ride/handling compromise.

Although I've currently set my tyres at 34 all round, and am reasonably happy with the balance, I may bump that up to 38 or so based on the feedback here. At 42 I certainly felt the car was a bit skittish, but as the tyres were brand new it's probably not appropriate to draw any major conclusions from that.

AMG

To put into perspective, I used to run my racing rubber at between 25-28psi.

Different compounds, and differenct wether conditions dictate different pressures

Wildcard

40psi all 'round for me.

sco

I'm running mine at 38 and pretty happy with it.... however ... if it drops 2 psi I notice significant differences in ride and grip.. will probably bump mine up to 40 psi next time I fill the tank.

Hymee

iTrader: (1)

Sco,

Could that really be you? Please validate your identity :D

I thought you had been abducted with Dez. How is he? Could you ask them to let him go as well?

Cheers,
Hymee.

Oooh! 1000 posts for me. (Did I tell you I found the post++ button )

Yeah!