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535i Andrew

18" winter tyres, what pressure?

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I've just completed my first trip out in mine with its 18" winter tyres at size 245/45 which is standard OEM size.

 

I inflated them to 2.5 bar at the rear which is as per sticker for 18" M+S tyres but I can't help but think this is a bit harsh.

 

What are others who have 245/45/18 winters (M+S) tyres running the rears at?

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On my land barge I’m running 38 at the rears and 32 on the fronts (PSI obviously) and find the ride to be superb and that’s on Sports suspension!

 

I know they’re different cars, but their weights won’t be too far apart and my winter tyres are only a tad bigger than yours

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37 minutes ago, d_a_n1979 said:

On my land barge I’m running 38 at the rears and 32 on the fronts (PSI obviously) and find the ride to be superb and that’s on Sports suspension!

 

I know they’re different cars, but their weights won’t be too far apart and my winter tyres are only a tad bigger than yours

 

How are those pressures compared to 'book'?

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What sort of driving do you do?.  Book pressures is just a "safe average" given from the manufacturers.

 

In reality people should monitor their own pressures and adjust accordingly to wear and usage.    Eg:  If your lugging a caravan around and your train weight is near around 3500kg, you should be running more than 38 psi on your rear tyres.

Also I have always found that running the "stated" 32psi on the front of BMWs always wears the edges of tyres but I do mostly motorway miles.    I run 40psi all around and my car has even tyre wear.  

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Of course, and there are different recommended pressures for light, part and full load (though usually I'm lightly loaded so lowest). I guess the 535D is fairly heavy at the front but I wouldn't have thought so much heavier than a 520D to go to 40 for lightly loaded - that sounds really high.

Edited by Boba

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Its not just about load as in weight, load is also placed on the vehicle with speed.   Myself I am rarely ever on B roads or in towns with this car so speeds are usually at national speed limits or greater when in Europe.

Then there is heat and pressure rise fall etc etc, but all of that is not needed for this point.

 

Simply put, if you have both outer edges of your tyres wearing quicker then the center, your pressures are too low.  If reversed, then your pressures are too high.   IE: middle 1/3 of tyre is wearing more then the outer edges.

 

 

Edited by Enzo503

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I do real mix of road driving. Twisty B roads, towns and motorways.

 

Only really me in the car, at most, the wife and littl'un and a boot full of shopping, or logs ;), so weight isn't really an issue. I only tow a half tonne trailer, but I'm not pushing it into the bends when towing. Lim set to 50mph towing.

 

Back out in it today and felt better although, I think I got a bit if a twitch from it on a couple of fast bends but the roads were only just wet from a few drops of rain so may have been a bit greasy, but in standing water on the return journey it was planted.

 

Tyres are Conti Winter contacts TS810, rft.

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As @535i Andrew said; I do mainly town/country roads and a bit of M6 to and from training (which is most of the driving I do every week) and 40PSI all round would be far too hard/high, more so for my 18" winter tyres

 

I've found 38 rears and 32 upfront to be very comfortable indeed. However, I am going to try 34 upfront and see if that makes a handling difference as the 7 is very front-heavy IMO

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