1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

18" wheel tyre pressures for a track day

Discussion in 'A3/S3/Sportback (8P Chassis)' started by RobB, Aug 1, 2007.

  1. RobB
    Offline

    RobB Member

    Joined:
    Nov 20, 2004
    Messages:
    317
    Likes Received:
    0
    Hi all

    I have the standard 225/40/18 Sline tyres (Continentals) on my 3.2 and normally have the pressures at around 37F/41R (the std pressures). With the car fully loaded they should be around 44F/44R, but what would you suggest for a track day?

    I am thinking around the 44/44 as this seemed to be better for me in terms of grip when I was hooning around Alpine pass hairpins last year but any advice gratefully received as obviously the Alps isn't quite the same as Brands Hatch.

    Cheers
    #1
  2. Amchlolor
    Offline

    Amchlolor Active Member

    Joined:
    Jan 13, 2005
    Messages:
    5,604
    Likes Received:
    3
    Do you increase car pressures for track use ?
    Bikes are the opposite,you reduce pressures for track use.
    #2
  3. Spin140
    Offline

    Spin140 Active Member

    Joined:
    Mar 2, 2005
    Messages:
    2,014
    Likes Received:
    28
    I've not done a track dy myself but remember a similar thread. Go for the max pressures recommended which will give you a stiffer sidewall, some even recommend an increase by 1-2 psi.

    Can't think why it would be the opposite way around for bikes but am sure someone will be along to enlighten us :)
    #3
  4. s3mike
    Offline

    s3mike Member

    Joined:
    Jun 26, 2007
    Messages:
    240
    Likes Received:
    0
    On my last bike track day they said to reduce the pressures, reason is it allows the tires to warm up faster and maintain a higher temperature - hence more grip.

    The manufacturer's recommend them higher on the road to cope with luggage / pillion and possible long high speed journeys on motorways. If the tyres get too hot they go bang which is not good.

    This is also why blowouts can often be caused by underinflated tyres.

    Not sure why car tyres would be any different, bike ones are probably a softer compound but I can't see why increasing the pressure would help on a track day.
    #4
  5. Amchlolor
    Offline

    Amchlolor Active Member

    Joined:
    Jan 13, 2005
    Messages:
    5,604
    Likes Received:
    3
    S3mike is spot on.
    Road riding means the possibility of high temperatures and loads for sustained periods,so high pressures are used.
    Track riding doesn't have the sustained high temperatures,so you can afford to reduce the pressures to offer a fatter footprint and faster warm-up.

    As someone else said,I can only assume you increase pressures in a car to stop the sidewalls flopping around.
    The fact the car will become twitchy and ride like a skateboard won't matter on a track.
    #5
  6. Spin140
    Offline

    Spin140 Active Member

    Joined:
    Mar 2, 2005
    Messages:
    2,014
    Likes Received:
    28
    its got to be cheaper to do a race day with car provided if you consider 4 new tyres and a full tank of fuel in your own car, but I guess the point is he wants to legally explore the limits of his own car, I'd never use my own because I happen to know for a fact there is nothing as fast as a car that belongs to someone else, especially hire cars )
    #6
  7. Amchlolor
    Offline

    Amchlolor Active Member

    Joined:
    Jan 13, 2005
    Messages:
    5,604
    Likes Received:
    3
    Despite being involved in track-based stuff for over 20 years now,I've never been tempted to take any of my own cars onto a track,even cars that have been faster than my current motor.
    Not because I'm scared I crash them,but because I can only imagine it would be intensely dull.
    The handling is going to be nothing short of lurch-understeer-screeeeech ,so I simply cannot see where the fun would be.
    Even cars which seem stiff on the road will turn into jellies on a track.
    Seen the way RS4's lurch around as pace cars for the BSB races ?
    I've been out in race cars though (Formula Ford type things and race-prepped XR2's).
    That was better,but you still had time to read a book down the straights.

    (I've also been involved in van races,after hours on race tracks,but that's another story...)
    #7
  8. leecs3
    Online

    leecs3 thinking about stuff

    Joined:
    May 13, 2006
    Messages:
    604
    Likes Received:
    2
    Reduce pressure for trackdays.
    #8
  9. RobB
    Offline

    RobB Member

    Joined:
    Nov 20, 2004
    Messages:
    317
    Likes Received:
    0
    I am sure you are right having done other days in someone else's car.

    I might never do one again in my own car, but I am just curious to have a go. Expensive curiosity I know and I'll probably go for the Hertz Focus next time.

    Thanks for all your comments.
    #9
  10. alfiejts
    Offline

    alfiejts Member

    Joined:
    Jul 8, 2006
    Messages:
    352
    Likes Received:
    4
    Back to the start of the thread - Rob where do you get the idea that the standard pressures are 37/41 for 225/40-18s?

    On mine, the specified pressure is 33f/30r standard and 36f/39r loaded.

    Now mine's a FWD 2.0TDI but I can't believe the model difference makes that much difference to the recommended pressures....
    #10
  11. Amchlolor
    Offline

    Amchlolor Active Member

    Joined:
    Jan 13, 2005
    Messages:
    5,604
    Likes Received:
    3
    Standard tyre pressures are all over the place.
    My 05 Sportback 2.0tdi S-line with 18 inchers is 38F/35R standard.
    It the first car I've had that is extremely pressure sensitive too.
    Unless they're spot on,the handling goes all stodgy.
    I've had to invest in a really good pressure gauge for the first time.
    My driver's side rear has also started losing pressure too.
    No puncture and new valve,so god knows.
    Maybe the alloy has gone porous or something.
    #11
  12. RobB
    Offline

    RobB Member

    Joined:
    Nov 20, 2004
    Messages:
    317
    Likes Received:
    0

    As Bowfer says there is a lot of difference between pressures depending on the model you have. Mine is the 3.2 and the pressures on the petrol flap are 41F/36R (admittedly got that one the wrong way round originally) but still 44 all round when fully loaded. Suppose it is the heavy lump of an engine up front that does it.
    #12
  13. Ess_Three
    Offline

    Ess_Three Active Member

    Joined:
    Feb 19, 2001
    Messages:
    5,383
    Likes Received:
    6
    I find that heading out on your normal fast road pressures first (which I run with the fronts usually at standard, or slightly under, and the rears above standard anyway)...doing a session to get them hot, then heading to the pits and setting them back to what you normally run as the pressures will be way too high.

    Or even on slightly less than your normal pressures as suggested...but re-set them when hot.

    My rear tyre pressures went UP by 1.5bar round the 'ring....let them down to standard fast road pressures measured hot, and all was back to normal.
    #13

Share This Page