Tyre pressure

[Sheldon13]

I am fairly new to the forum and would like to know some stuff.

i would like to find out whats the correct tyre pressure for an E90 with 18" narrows and wides. front tyres are 235/40/18 and rear is 255/35/18.
it states on the door that its supposed to be 2.2 bar but that seems low and the car seems jittery.

also does the motorplan cover wiper blades.

 

[abmi0000]

The pressure on your door is correct because you are spec'd to use RFTs. Are you still running with RFTs? What does jittery mean exactly?

Yes, they cover it!

 

[Sheldon13]

thanks for the info

still got rft's
got michelin pilot sports and they have close to 80% life on them

seems twitchy when going round bends.

 

[abmi0000]

What suspension?

Doesn't sound right. Either you are pushing too hard or the tyre is over inflated

 

[Sheldon13]

my car is the exclusive pack and there has been nothing done to it so the suspension is standard.

 

[abmi0000]

Like I say, you're pushing too hard or the garage that filled pressure has faulty readings on the pressure gauge and pumped more than required. I have had pressure at 3.1bars when asking for 2.4 so check with your own gauge. Go out and buy one.

Can you compare handling on the same bends with another car?

 

[moranor@axis]

does the door not give you different pressures for the rear? 2.2 seems low for the rear...

 

[abmi0000]

does the door not give you different pressures for the rear? 2.2 seems low for the rear...

Should be different on a BMW

 

[Sheldon13]

Like I say, you're pushing too hard or the garage that filled pressure has faulty readings on the pressure gauge and pumped more than required. I have had pressure at 3.1bars when asking for 2.4 so check with your own gauge. Go out and buy one.


Cool.. will get one and have a look

Can you compare handling on the same bends with another car?

My Audi handled much better around the same bends but thats an sline with a lowered suspension.

 

[moranor@axis]

also the pressures are for cold tires so you really need to check them before you leave home or they will be under inflated...

 

[Sheldon13]

does the door not give you different pressures for the rear? 2.2 seems low for the rear...

the door does and it shows 2.2bar

 

[moranor@axis]

if you checking them cold and the pressures are as recommended then the problem must be elsewhere...

 

[Sheldon13]

if you checking them cold and the pressures are as recommended then the problem must be elsewhere...

Cool.. will have a look at it tomorrow morning

 

[abmi0000]

And dont compare sport suspension to standard.

 

[Dhp507]

Sorry if I seem like im jacking the thread - but Im running 17's with 225 all round. It tells me to inflate the fronts with 2.1 Bar and the rears 2.5 Bar. Note mine is an e46. I think thats a bit low.

I have my own gauge as I did figure out the garages don't calibrate theirs.

Your thoughts?

 

[abmi0000]

Sorry if I seem like im jacking the thread - but Im running 17's with 225 all round. It tells me to inflate the fronts with 2.1 Bar and the rears 2.5 Bar. Note mine is an e46. I think thats a bit low.

I have my own gauge as I did figure out the garages don't calibrate theirs.

Your thoughts?

Why do you think that it is low? Pressure is determined on the car's weight and tyre profile. One car isn't the same as the next.

 

[AshG108]

what E90 do you have, the 18 inch specs are normally 225/40/18 for the front and 255/35/18 for the rear. seems you got slightly wider tyres at the front?

 

[Sheldon13]

what E90 do you have, the 18 inch specs are normally 225/40/18 for the front and 255/35/18 for the rear. seems you got slightly wider tyres at the front?

sorry.. just checked now and they are 225/40/18 for front and 255/35/18 at the back

 

[Dhp507]

Sorry if I seem like im jacking the thread - but Im running 17's with 225 all round. It tells me to inflate the fronts with 2.1 Bar and the rears 2.5 Bar. Note mine is an e46. I think thats a bit low.

I have my own gauge as I did figure out the garages don't calibrate theirs.

Your thoughts?

Why do you think that it is low? Pressure is determined on the car's weight and tyre profile. One car isn't the same as the next.

Here is my explanation. 50.1 - 50.5 weight biased to the front of the vehicle. That would be split equally to each end - Right & left. Now If you are inflating the the rears at 2.5 . Why would you keep the front at 2.1.

 

[abmi0000]

Sorry if I seem like im jacking the thread - but Im running 17's with 225 all round. It tells me to inflate the fronts with 2.1 Bar and the rears 2.5 Bar. Note mine is an e46. I think thats a bit low.

I have my own gauge as I did figure out the garages don't calibrate theirs.

Your thoughts?

Why do you think that it is low? Pressure is determined on the car's weight and tyre profile. One car isn't the same as the next.

Here is my explanation. 50.1 - 50.5 weight biased to the front of the vehicle. That would be split equally to each end - Right & left. Now If you are inflating the the rears at 2.5 . Why would you keep the front at 2.1.

Downforce due to accelleration and wind resistance.