Direzza tire pressures?

Discussion in 'Fiesta ST Autocross' started by AlanBDahl, Apr 8, 2014.

  1. AlanBDahl

    AlanBDahl Active Member

    Just wanted to create a thread to discuss tire pressures as people seem to be all over the place and I can't imagine the there isn't a sweet spot.
     
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  3. k757

    k757 Active Member

    205/50-16

    For my driving style, the pressures best for me are 40F/38R. I may bump the rears to 40 to see if I get more response for the smaller/tighter auto-x courses. So far, I have had better results in Sport mode and not OFF, but I am coming from an AWD WRX, so I'm still learning what I can and not do with FWD. My settings may change over time.

    Lower than those and I roll onto the indicators. Much more than that and I don't get out to the edges
     
  4. AlanBDahl

    AlanBDahl Active Member

    225/45-16

    Mine seemed to work well at 40/36 at the last event but I am not close to done testing. I also haven’t yet aligned the car and I’ve done nothing in the way of shocks or swaybars.
     
  5. Mightymango

    Mightymango Active Member

    I have mine set at 40/35 currently. Still testing.
     
  6. Mr UFO

    Mr UFO Active Member

    Fastest times for me have been at 36/32
     
  7. McRib 1s Back

    McRib 1s Back Well-Known Member

    Those are close to what works for me, hot. I aim to keep the front closer to 34 for road courses. Keep in mind that I'm running nearly -3 degrees of camber up front. If you can swing it, you gain good mechanical grip at lower pressures.
     
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  8. k757

    k757 Active Member

    Yesterday, I had my best run at 40f/40r on a small tight course. (Sport mode)
     
  9. Joshesh

    Joshesh New Member

    Where I have settled after about 5-6 events in the FiST.

    Fronts 225/45/16 ZII - 39-41 psi
    Rears Stock tires - 55-58 psi

    No rear bar, no shock upgrades, no alignment, just front tires and this happens:

    [​IMG]
     
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  10. Mightymango

    Mightymango Active Member

    Ran 36 front and 34 ish rear yesterday in the rain with 40 degree temps. The car didn't push and it rotated very well. When it dried a bit the car was full of grip and was lifting the inside tire constantly. I myself only drove it in a downpour but it still had plenty of grip in the cold/wet.
     
  11. Smokin

    Smokin Active Member


    Where are you located?

    The Lincoln event was called at 10 AM Sunday d/t the extreme weather.
    I cancelled Friday night because of the extreme weather, so no results from this weekend.

    I won't be running on an all asphalt course until a double regional at Heartland Park July 13th.
    That's where I think 36 psi fronts will work. Until then on airbase-type concrete, still need 40-42 psi fronts or it just grinds away the shoulders....
     
  12. Mightymango

    Mightymango Active Member

    Minnesota on all Asphalt. The car was used by two students/friends and I only got to drive it during instructor runs. Seriously these cars are very capable auto-x cars and I see them being very good at most events. The gearing though for Lincoln events may be a bit short
     
  13. AlanBDahl

    AlanBDahl Active Member

    I ran my ZII's at 40/37 on asphalt in wet conditions yesterday and the car was fantastic.
     
  14. Mightymango

    Mightymango Active Member

    I ran 36/32 when it was around 40 degrees on the first runs on Sunday and they were fine until it started to actually warm up . I bumped them up to 40/37 (same as Alan) and it rotated well, this was with ambient temps near 56


    This picture was during the afternoon runs

    [​IMG]
     
    Last edited: May 6, 2014
  15. CrookedRacer

    CrookedRacer Active Member

    At my recent night autocross, I started out 40 front / 40 rear, and thought it felt a little sloppy.

    42 up front was noticeably slower. Lots more wheelspin, probably due to a smaller contact patch.

    So I went down to 38 and got my best time. Sloppiness did not increase.

    Next time I will start at 37 /40 and try +/- 2 from there.
     
  16. conevadr

    conevadr New Member

    This is pretty much where I ended up as well. I usually start at 55 in the rear and have gone as high as 60 to encourage rotation. The 39-41 range on the front depends on grip levels and clockwise/counter-clockwise orientation of the course. The predominately outside front tire goes 40-41, with the inside at 39-40. Lower than that starts to create too much rollover, and too much more creates more wheelspin.
     

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