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Stradale Tires: Chunking Problems? Pressures?

Discussion in '360/430' started by Brian C. Stradale, May 7, 2004.

  1. Brian C. Stradale

    Brian C. Stradale F1 Rookie
    Lifetime Rossa

    Mar 17, 2002
    3,603
    Dallas, TX, USA
    I took my Stradale to the track today (click here to read about that)... the car performed great. The tires did not.

    In particular, towards the end of a session, I started pulling chunks out of the tread in the corners.

    I know another Stradale owner who experienced the same... in fact, he had FMoD replace the fronts... I saw the old ones... lots of big chunks all the way around!

    Any of you other Stradale owners had any issues with the tire performance on the track? Any of you experience any chunking problems? Any of you have more tire rubber on your wheels than brake dust?

    What pressures are you guys running on the track?
     
  2. 4i2fly

    4i2fly Formula 3

    Apr 16, 2004
    1,330
    SF, Bay Area
    I am glad to see you take your brand new CS to the track. How was the experience other than the tire situation? I think what you see is normal for those tires.
    I have a 360 and I am on my 2nd set of tires (Pilot Sports and now P0’s). When I track my car one can see the rubber sort of collecting at some parts on the surface of the tires. I think it is worse on the P0’s, and may have something to do with threadwear (120 and 220 for Pirelli and Michelin respectively). The Stradale tires are rated at threadwear of 60 so, I can imagine it will be worse.
    On the tire pressure, I always run a couple of pounds more for the track in the tires and monitor the wear when I come out to the pits. I look at the wear very carefully and adjust the pressure accordingly. I pay close attention to the wear on the sides. If it is too much need more air if it is too little meaning the thread on the side is not getting worn, I take a few pounds. But I would start with the factory recommended plus a couple or three pounds more.

    Cheers,
    Matt
     
  3. Scotty

    Scotty F1 Veteran
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    Oct 31, 2003
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    Brian--Have your tires been heat cycled? Did you take your first laps at 6/10's to slowly warm them up? What was the track temperature? Air temperature? Sorry--lots of questions.

    On thing would have been useful is an infrared pyrometer. This is a gizmo that provides "touchless" temperature readings. Next time you are at the track, see if someone has one and read the outer, middle and inner termperature (across the width of the tread)--that might give you some clues if you haven't figured it out by then.

    Of course, the likely reason is that you were doing track things on full depth street tires, and street tires just don't handle that sort of thing that well. I think the Tire Rack website (www.tirerack.com) has good info on heat cycling and tread shaving tires for track use.

    Time for either track/street tires, or a second set of wheels (CHA CHING).
     
  4. Scotty

    Scotty F1 Veteran
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  5. Scotty

    Scotty F1 Veteran
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  6. WCH

    WCH F1 Veteran
    Rossa Subscribed Owner

    Mar 16, 2003
    5,179
    Anyone aware of any track tires for the Stradale? I have not heard of any yet.

    Brian, thanks for the debrief on your track experiences, very helpful for other Stradale folks. If I can get to a track soon, I'll try to take temps and pressures systematically - might even use the old shoe polish on the tire edge trick.

    Will
     
  7. Izza

    Izza Formula 3

    Nov 3, 2003
    1,046
    London
    I have a spider but run it on CS rims and tyres. On the road I have had no problem but a friend of mine is a nominated test driver for Ferrari in France. He had the first CS in France and suffered the same issue as you. This was especially bad on Magny Cours since the back straight allows you to get to top speed before arriving at a hairpin which has to be taken at 30mph in second gear. He went through 3 sets of tyres in 3 months of CS ownership!

    However, when I saw him recently we talked about this issue and he said that the CS tyres are now made of a slightly harder compound. This had stopped the chunking occuring.

    I would recommend seeing how your second set goes before looking elsewhere.
     
  8. Mitch Alsup

    Mitch Alsup F1 Veteran

    Nov 4, 2003
    6,992
    Get a tire probe-point pyrometer and take some temperature readings.

    You want the middle temperature to be the average of the inside and outside temperatures. Too hot->overinflated; not hot enough->underinflated

    You want an even gradient fron outside to inside and the inside 10dF to 20dF hotter than the outside. Inside hot->too much camber; outside hot->not enough camber

    One result might be that the suspension is just fine and the capabilities of the car are beyond the work capabilities of those tires. A pyrometer is the way to know.
     
  9. Brian C. Stradale

    Brian C. Stradale F1 Rookie
    Lifetime Rossa

    Mar 17, 2002
    3,603
    Dallas, TX, USA
    Heh... you didn't "click here", now did ya? ;) (see above... and click)


    I am very accustomed to R-compound tires... its not rubber stuck to the tires... that's normal... its chunks of rubber missing from the tires that's a problem.


    That's about where I was, and I was getting good wear to the edges, but not over the edges at all. So, I had enough pressure, though perhaps too much. But I wouldn't think 32# cold would sooo too much that it would justify chunking.
     
  10. Brian C. Stradale

    Brian C. Stradale F1 Rookie
    Lifetime Rossa

    Mar 17, 2002
    3,603
    Dallas, TX, USA
    Yes, the tires got a good heat cycle almost every day I've owned it (about 11 heat cycles prior to today).


    First lap is at about 7/10ths to warm the tires... they're not too grippy cold.


    Mid-80's today; overcast, so track wasn't much hotter... but I didn't measure it.


    Actually, I have one. I used to keep it in my 360 glove box so that I could take quick measurements with the car "at temp". The Stradale has no box, so I had left it in the clubhouse. Had I known I'd have tire issues, I'd have probably tucked it in the mesh holders in the back. I'll do that next Friday so that I can get some accurate measurements.


    Yep, but the problem is those ARE track tires... or supposed to be. But it may be they need shaving. Unfortunately, you can't buy them through TireRack and I don't think Ferrari offers tire shaving.

    I'd switch to Michelin Pilot Sport Cups, but they don't come in 19" sizes yet. I've used the Kumho ECSTA V700's on my Modena... but again, none in 19" sizes. And no, 18" wheels won't fit over the Stradale brakes.
     
  11. maranelloman

    maranelloman Guest

    Brian, I am sorry about your tire problems.

    It is highly likely that I will be at MSR next Friday, at least in the afternoon. I am instructing that weekend for a PCA event there, and another MSR member has invited me & a friend up for a member's day. Depending on weather, I many bring the 550...although I suspect that is may be a bit too much car for MSR, especiallyon the crap Pilot Sports I currently have.

    Anyway, I hope to see you then.
     
  12. thomas_b

    thomas_b Formula Junior

    Sep 15, 2003
    765
    what was the tire / wheel temperature? – I found the tires to be really! hot even after some cool down time – one guess I have is that the carbon fiber disks store & radiate a lot of heat – this could push temperature to the tire limit and could be a reason for chunking – it is hard to check since tires change temperature so fast and measurements after a cool down lap are next to useless – note that an infrared pyrometer does not cut it; you need to penetrate the surface to get a reasonable picture; you also need to stop fast

    one other thing – I don’t consider the CS run in after 500 miles – not sure about the tires but the brakes and the engine change behavior significantly after 1000 – 1500 miles – can’t remember the tire run in period 200 miles? but new tires generate more heat until they are broken in
     
  13. spyderman

    spyderman Formula 3

    Nov 4, 2003
    1,469
    Toronto - Canada
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    Spyderman
    Brian,

    Have you heard if Michelin is coming out with Sport Cups in the 19" soon? I am having some serious reservations about tracking my Stradale knowing that the tires will not be up to the task of some good lapping :(

    I recall taking out my 996tt with an Evo Stage 4 kit with 600 HP equipped with the Sport Cups and with the proper tire pressures (and brake pads) I could lap at 10/10ths until the gas tank ran dry :) The 996tt was about 400 lbs heavier then the Stradale and yet the Sport Cups just kept on going without loosing any grip, it was an assume tire for the track!!
     
  14. Brian C. Stradale

    Brian C. Stradale F1 Rookie
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    Mar 17, 2002
    3,603
    Dallas, TX, USA
    No, but I haven't been researching it at all... until now. I'll let you know what I find out.


    Oh, sheesh, don't let that stop you! Every Stradale needs to see the track!
     
  15. Brian C. Stradale

    Brian C. Stradale F1 Rookie
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    Mar 17, 2002
    3,603
    Dallas, TX, USA
    Perhaps, but didn't seem particularly hot to me. And if they got that way today, they have no prayer when I cut another 2 seconds off my lap time in the next couple months, and its 100'F air temp and 120'F track temp.


    Yep... to see absolute temps. Not sure I'll be willing to do that given I don't want to risk damaging the brakes. At least not until I have some good confidence in the brakes holding up well. The infrared pyrometer is fine for quickly measuring the temps to see if there is a delta inside vs. middle vs. outside.


    The tires should be pretty run in. Especially after the lunch break following the second session.

    The engine may continue to "mature" for several thousand miles... I know my M3 improved markedly up to about 8k miles... others have claimed it didn't peak out until about 20k miles.
     
  16. Brian C. Stradale

    Brian C. Stradale F1 Rookie
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    Mar 17, 2002
    3,603
    Dallas, TX, USA
    Only if you bring the 550! ;)
     
  17. jakermc

    jakermc Formula 3
    Owner

    Jan 17, 2004
    1,778
    Palm Beach, FL
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    Rob

    I will be at the DE as well, driving a 1983 white 911 with a ducktail. Car #90. Drop by and say hello. If I can get there early enough on Friday, I may catch the last member session as well.
     
  18. maranelloman

    maranelloman Guest

    I will, Rob. What PCA group are you in?

    If I don't bring the 550 (for instance, if it is likely to rain), I will have a silver 1997 M3.
     
  19. jakermc

    jakermc Formula 3
    Owner

    Jan 17, 2004
    1,778
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    Rob
    I'll be driving Blue Solo. If you happen to become free during the Blue group, maybe you can come for a ride and provide some instruction. I expect to be very rusty as I have not driven the course CCW since November.

    I'm having some mechanical issues in my 911 right now that might also force a car change as well. If I can't get them sorted out I'll be bringing either a white 968 or maybe even the 355.
     
  20. maranelloman

    maranelloman Guest

    Will do! I usually will be given a Green & a Blue student. With any luck, my Blue will Solo during the weekend, so I may have some free time to work with you.

    Best,

    Dave
     
  21. thomas_b

    thomas_b Formula Junior

    Sep 15, 2003
    765
    there is a Pirelli warranty flyer in the car manuals set - I states that racing or other competitive events are not covered - however to talk to Pirelli might be some way to get a response for why
     
  22. PSk

    PSk F1 World Champ

    Nov 20, 2002
    17,673
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    Pete
    Chunking that you have described is caused by the tread blocks being too tall and thus not supported enough. Only solution is to shave the tyre down to say a 3mm tread depth.

    Basically the tread compound is TOO soft to have that smaller tread block OR that deeper tread.

    I assume that the CS comes with Bridgestone tyres?, but I am amused that Bridgestone have not resolved this issue. They had the same problem with their RE71r tyres that were street legal but a supposedly racing compound.

    I have used the RE71r tyres AFTER shaving them and they are a great little tyre but I have also seen people fnck them in ONE race meeting because they ignored the advise to shave them.

    Bit worried that Bridgestone are that thick :D

    EDIT: Just read that they are Pirelli tyres. Same issue just different supplier ;)

    Pete
     
  23. WCH

    WCH F1 Veteran
    Rossa Subscribed Owner

    Mar 16, 2003
    5,179
    Just ordered a set of shaved Corsas, should have them in a few weeks. Now I need an extra set of wheels. Wish I'd picked a cheaper hobby ....
     
  24. WCH

    WCH F1 Veteran
    Rossa Subscribed Owner

    Mar 16, 2003
    5,179
    Extra set of wheels on order. OK Brian, I'm coming after you ....
     
  25. robinh

    robinh Formula Junior

    Jan 3, 2004
    622
    Cambridgeshire, Engl
    Full Name:
    Robin
    There are no cheap hobbies - a friend of mine spends thousnads of dollars on his bicycle, tens of dollars on titanium nuts and bolts, carbon fibre this and that, sadles, wheels, spokes, shoes, cloths, everything. His current bike frame alone cost around $3k and he's no Tour de France winner, just a hobby!!!!!
     

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