265 Tyre pressure's on track

Discussion in 'Suspension, Brakes, Wheels & Tyres section' started by Mike265cup, Feb 19, 2015.

  1. What tyre pressure do you run on track, and do you get much fluctuation in psi between hot and cold?
     
  2. Depends what tyres your using start off around 32 check and adjust after a few laps
     
  3. Nankang ns2r in medium compound. What do you set them at when hot?
     
  4. I just try and keep mine at around 32, you will know when their to hot as you'll lose grip, little bit understeery then come back in check them and you will find they've gone up a few psi, let them down and go out again
     
  5. -Jamie-

    -Jamie- RSM Moderator

    Need more than 32 in those tyres/

    I ran 36 Front and 32 Rear. Hot pressures

    Non R rated tyres need more pressure in them to keep the sidewall stiff, Even more so on standard suspension as you don't have much camber so the outside edge gets destroyed.

    I done 260+miles in one day at Snett on the NS-2R's and they had barely worn, Was very impressed. Get pressures wrong and you will destroy tyres though. I done a set of brand new RSR's at Knockhill in one day as i had them too low
     
  6. 260 plus laps in 1 day ? You sure
     
  7. -Jamie-

    -Jamie- RSM Moderator

    Miles Steve and yes I'm sure. I always measure my trackdays in miles and don't think i have ever bothered to count them by laps...
     
  8. even im confused, even if you measure your trackdays in miles the 100 snet circuit is 1 mile long, hence 260 laps lol, maybe you meant the 300 circuit which is 3 miles long so 86 odd laps :smile:
     
  9. -Jamie-

    -Jamie- RSM Moderator

    200 layout.
     
  10. Front tyres take a hammering on track so do some laps, adjust, do another 3-4 adjust back down and they should plateau just need the odd tweek.

    run them too high you will eat tread unevenly and have worse traction

    Sure i ran mine like 28 front 32 back on the r26, definately more on the back anyway got a much better turn in
     
  11. Like I say I'm happy with mine around 32ish up to 38 on the front if using R888s
     
  12. same here Steve, anything above that on mine and the understeer rears its head.
     
  13. -Jamie-

    -Jamie- RSM Moderator

    Different cars/setups
     
  14. 32 front definitely isn't enough on the 265, I ran the PS2's at that pressure on the last Knockhill outing, could feel the tyre 'folding' if you like, no one had a pump so I just had to persevere.

    Why up to 38 psi with 888 on Steve?
     
  15. I've ran them in the summer at that and they just don't seem to understeer around that psi, even at 40 they were fine a bit like the direzza they can also take some stick at a higher psi it just seems sharper when their around 32 must be the fact they have a bigger foot print , I did a few laps last off at oulton the other week with the pilot super sports they were at 34 front did 4 laps in the freezing cold , all of a sudden the grip dropped off quite quick got back to the pits and both were up at 44psi, they heat up very quick
     
  16. I'll need to have a mess about with them next month at the ring see what I settle for. 32-36 seems to be a start point and go from there. The sidewalls on the nankangs are solid so that'll hopefully solve some flex.
     
    Illisha likes this.
  17. The direzza are a really tough tyre, one of the best semi slicks on the market
     
  18. Spoken to a few people who swear by them. Will eventually buy a second set of wheels so I can keep a 'proper' set of semis for dry days.
     
  19. At £200 per corner their not cheap but they will last twice as long as a tyre costing £150 so in comparison their cheap, just getting your head round the initial out lay , I've got 6 direzza like new 2 R888s like new a brand new set of pilot sup sports for road and wet track
     
  20. At the end of the day if they're as good as that then I wouldn't grudge paying for them. I ran the AD08 for a while and tbh I don't think they're worth the money compared to some equivalent tyres that are cheaper.
     
  21. My next tyre will be the new pilot sport cup 2s or what ever their called
     
  22. I'd like to try them
     
  23. Meant to be very direct but also very soft, like minimal life
     

  24. Sorry to bring up an old thread, if your had ns2r on medium compound. What would you set them at as a cold pressure.
     
  25. -Jamie-

    -Jamie- RSM Moderator

    Don't know, Cold pressures mean hee haw.
    Set them to whatever the book pressures are an adjust when hot
     
  26. DV8

    DV8

    I was at Spa last week and dropped them by about 4 psi all round over the desired results. Then checked after one session and they were sky high so dropped them even more.
     
  27. -Jamie-

    -Jamie- RSM Moderator

    My AR1s were 13psi cold at Spa which translated to 28psi hot lol
     
  28. DV8

    DV8

    Makes the drive back to the hotel fun if you dont have a tyre inflator with you :tearsofjoy:
     
  29. -Jamie-

    -Jamie- RSM Moderator

    Seperate wheels for track so no issues there haha.

    Cold pressures were totally different at Knockhill to Spa again recently, so there's no point in quoting cold pressures imo.
     
  30. DV8

    DV8

    Totally agree, but you can guarantee that tyre pressure will increase when on track so for me personally I would always lower a bit before going out so that your are not driving around with insane pressures (especially if you are limited to a few sessions). Then re-check when you come in and adjust.
     
  31. -Jamie-

    -Jamie- RSM Moderator

    Yeah I get what your meaning, see a lot of people quoting cold pressures in track without the slightest sniff of what the actual hot pressures are.

    I tend to stick 30 in mine and bleed them as needed
     
  32. if i go out with 32 ish i have to drop on average 12 to 14psi to get them to stabilise at 32ish when hot, probably worth if you have semi slicks going out with 25 front and 27/8 rear cold then come in dropping the pressures to the pressure you want after a few laps, going out with cold tyres and pressures at the right value will only mean you will have to come in sooner as they will go off grip when pressure too high.

    i recently did a slip and grip day at castle combe and the wait times to get back on track were stupid (40mins). some tracks you can nip in, adjust pressure and get straight out again.
     
  33. So an update to this.thruxton yesterday...-3 camber front and -1,5 rear...I had part worn zzrs which I put on the rear. And brand new ar1s on the front. Got them hot and ran pressures of 31 33. Car felt not right and as Ian said floaty which summed it up nicely. I had also had my geo touched by a local garage on Thursday to adjust the toe so wasn't sure if he had "touched" anything else. I had run pressures of 32 34 a couple of weeks ago at thruxton but with zzr all round. So we scratched our heads. Decided to switch round the tyres and have zzr on front and put ar1 on rear...i upped the pressures of the rears and went out. Car totally transformed and handling brilliant and very surefooted. Tyre pressures hot were 3736. Didn't bother tweaking them or swapping back round to see if the tyre choices worked better that way round as it felt so good.
    I did post a pic of a tyre a week or two ago with severe wear on the inside went all the way through the steel cords. That tyre wear was due to toe being out and probably tyre pressures being a bit too low.
    Hope that helps others.
    Next setup will be r888 255 on the front
     
  34. -Jamie-

    -Jamie- RSM Moderator

    I run 29/35 hot in my AR1s, they need more pressure in the rear to work on the Meganes

    AR1s need scrubbed and a heat cycle through them as well when new. Mine were pretty sketchy until I had done that
     
    timbo likes this.
  35. Ah that's interesting
     
  36. NJH

    NJH

    This is the best starting point advice for all cars and all tyres.

    Thing is there is no magic easy answer. If one wants to get all technical about it to find the ideal you will need to buy/borrow a pyrometer and start taking measurements in a controlled fashion.

    Also playing around with tyre pressures to alter a cars handling balance is fundamentally the wrong way round. I think we all know that but can accept it as a small adjustment if one is not in a position to adjust spring rates, damper settings and camber.
     
    -Jamie- likes this.
  37. So on the eve of my first track day in the Megane, I'm taking a look at pressures. My CTR on standard pressures ended up almost 50psi after a 20min session at Pembrey.... They were rock hard to touch and understeer was present in large doses.

    Its an open pit lane, so ill be aiming for hot stock pressures...
     

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