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Pirelli tire selection

Discussion in 'Tech' started by Pneumatico Delle Vittorie, Jun 15, 2018.

  1. Blue Junk

    Blue Junk Well-Known Member

    Find the compound code, next to the date code. There are a couple tires out there that don’t have a SC designation sticker. They’re my favorite. Lol
     
  2. Pneumatico Delle Vittorie

    Pneumatico Delle Vittorie Retired "Tire" Guy

    That you Cory?
     
  3. Blue Junk

    Blue Junk Well-Known Member

    Hi Jeff!
     
  4. Pneumatico Delle Vittorie

    Pneumatico Delle Vittorie Retired "Tire" Guy

    And a holiday bump, happy fourth
     
  5. ronin1052

    ronin1052 Well-Known Member

    Alright, gonna stick my neck out a bit & hop in w/ the sharks...

    Trackday only, Mid-Intermediate pace (i.e. fat, middle-aged slow guy).

    Diablo Rosso Corsa II. Not a lot of data/info out there on these.
    Three trackdays in so far, kinda settled on 30F / 28R cold pressures.
    Pirelli first-timer; they feel pretty good, much different (softer, more feedback) than S21s they replaced.

    Am I in the ballpark, as in the 'correct' ballpark?

    Any info is appreciated, thx in advance.

    .
     
  6. Pneumatico Delle Vittorie

    Pneumatico Delle Vittorie Retired "Tire" Guy

    I did a bunch of press launches with Ducati and others over the years with Rosso IIs. So what bike and tire size and at what track please?
     

    Attached Files:

  7. ronin1052

    ronin1052 Well-Known Member

    Heavily modded Suzuki TL1000S; 120/70-17 front, 190/55-17 rear.
    250# rider w/o gear (I'm workin' on it...!).

    Track time was/is at The Ridge Motorsports Park in Shelton, WA.
    Smooth, newer circuit (2012), not known as being particularly abrasive or tough on tires.

    Moderate PNW climate, daytime temps typically 60*F - 85*F during track season.

    .
     
  8. Pneumatico Delle Vittorie

    Pneumatico Delle Vittorie Retired "Tire" Guy

    The Rosso Corsas and the newer Rosso Corsa IIs are run at these pressures, 32-36 front & 29/32 rear hot, so you are in the range just tweak the psi a bit, and then print the data sheet from the earlier post. Have fun.
     
    mpusch likes this.
  9. noles19

    noles19 Well-Known Member

    Are you checking your pressure when you get off track?
     
  10. ronin1052

    ronin1052 Well-Known Member

    Yes. I typically see 3 PSI rise from cold to hot-off-track - which is consistent with published Pirelli info.
    I just don't push hard enough to see any greater rise...I'm working on that.
    Next event is in 3 weeks; I think I might try 29/27 (or even 28/26) cold, at least in the morning before the track heats up.

    FWIW, my gauge is within 0.5 PSI of NIST-calibrated gauge of local tire vendor.
    And I use my gauge exclusively, to mitigate absolute:relative measurement error.

    .
     
    noles19 likes this.
  11. noles19

    noles19 Well-Known Member

    Good job! Just as a way to make it easier I'd suggest telling the hot off the tracktemp anytime you talk to a tire guy, there is a lot less guessing with hot of track vs cold.
    Because you're never completely sure how much pressure someone is gaining obviously.
    3 pounds gain is in the right window for what you should be getting imo
     
  12. Pneumatico Delle Vittorie

    Pneumatico Delle Vittorie Retired "Tire" Guy

  13. ilikebass

    ilikebass Active Member

    Ok Pneumatico, I have one for you.

    I'm racing a Daytona 675 and am leading the amateur championship here in New Mexico at Arroyo - for perspective I am at a mid-pack expert pace right now. I recently switched from Dunlop slicks to Pirelli and the softer carcass is really helping soak up the bumps which is allowing me to stay on the throttle longer with more confidence. So I am faster now, thanks Pirelli.

    I am running SC1's front and rear and they are wearing nicely. I can start feeling the rear letting go under hard throttle on corner exit but I really feel like the front is planted. I put a new rear on every race day and run that the practice day for the next round. So basically a new rear every round. My question is at what point should I be replacing the front if I cannot feel it sliding? Should I be keeping it on until I do feel it giving out a little? I don't want it to be unpredictable/dangerous, and I have to admit I don't have an overly adept feel of the front so I tend to replace it more than I really need to just to avoid a sudden front-end event. I'd like to stop replacing more than necessary. People say a front end slide should be gradual provided you are smooth, which is something I think I do have going for me. Is it reasonable to get 4 days out of a front? This would get me on a 2 rear to 1 front schedule. Based on wear it seems like I should be able to get more time on the front but I don't know about heat cycles, is 4 acceptable before replacing? What is the philosophy on replacing tires if you are not having any immediate signs of loss of grip?

    PS I forgot to bring up compounds, like maybe going to an SC2 front.
     
  14. Pneumatico Delle Vittorie

    Pneumatico Delle Vittorie Retired "Tire" Guy

    Sorry I was out on the boat today. I always suggest tracking laps/mileage, suspension settings, air pressures, etc. after any track time with the bike. Along with that check your clickers often to make sure they are where they should be. And with notes you can compare them as time goes by to make sure you are progressing. I expect you will see the front move a bit more with X amount of mileage and heat cycles and once you get a tuck or push that you don't like change the front. And keep an eye on the warmers too, make sure they are working properly ALL OF THE TIME. And watch your hot psi and pressure rises along with making sure your gauge is accurate.
    Yes I would think so but I never made it to Arroyo during my travels. Just track the heat cycles/mileage and replace the tire when you feel it needs to, and this applies to any track.
    Knowing where you are at with mileage and heat cycles is the key, and I think you will find a point of when it's time to replace the tires.
    The SC2 front does last a bit longer and it has a firmer feel. But don't think that it isn't as fast as a SC1 because it is. So maybe try one in the future and you may like the feel too? Finally make sure you look at the front travel to make sure you aren't bottoming. Sometimes peeps can't feel the difference between the front squishing on the bump stop or that you are compressing the tire sidewall. Get it wrong and you'll tuck the front. Hope that helps.
     
    Last edited: Sep 1, 2020
  15. ilikebass

    ilikebass Active Member

    To your points: I keep track of the days and typically a day will give me about 100 miles. I have my clickers exactly where I want them, depending on track I'll be +/- 2 clicks. I run 32/25 (f/r) hot off the warmers currently and the wear is nice and even. Warmers are 6 months old and seem to be working fine. I have 3 mm of unused fork travel that I'm sparing for the off-line surprise bump (this has happened before during a sketchy pass and I bottomed bad).

    What I got from your post was keep track of laps and figure out at what point the tire starts to move on me, then I'll know when to change them so it does not happen? If you are smooth should the front let go softly so that you can tell that it pushed but it will not give out completely so that it is not "dangerous" to do? I realize that I'm changing the front more frequently than I need to because I'm trying to give myself some safety margin, but I would really like to figure out when it's actually necessary. I have only felt the front end push a few times so I'm not that familiar with the feeling, hence the apprehension.
     
  16. ilikebass

    ilikebass Active Member



    @ 6:23 he explains that higher tire pressures lead to an increase in tire temperatures, which is the exact opposite of what I thought! I am understanding what he's saying though. So does this mean that when track temps are down instead of dropping pressures like I would normally do to get more heat into the tires, you should be increasing pressure?? I plan on testing this at the track with my infrared gauge asap, this seems crazy to me.
     
  17. Pneumatico Delle Vittorie

    Pneumatico Delle Vittorie Retired "Tire" Guy

    You don't a temp gauge and you're over complicating things, all you need to do is follow this well accepted process and ride the bike then adjust as needed.

    Tire Pressure
    Get a good gauge then get the tires on the warmers. Once you’re ready to go out set the correct HOT psi. Then ride and when you get back check the pressures off the track. You’re looking for around a 2-psi increase. If higher or lower adjust accordingly to the correct hot psi settings listed on the attached tech sheet. And if you keep the pressures in our suggested range and find what you like you will be happy. And when it’s cold and the pavement is almost frozen there is no magic way to get your tires up to 170f with air pressure. You need to ride within the current weather conditions and deal with it.
    Warmer use
    When the bike is off the track warmers are used to prep the tires for the next session/race and also to help control heat cycles. Harsh heat cycles cause the compound to change for the worse and you can lessen this effect by helping your tires cool down slowly with the warmers. Some riders leave them on all day and some do not, so you can decide what works best for you. But if you have 2 or 3 races in a 2-hour time frame just leave them on. It’s important to note the tire pressures and warmer for each type of tire. When it’s raining the track temp is much lower and the flying water acts to cool the tires. So, using dry tire settings doesn’t help because they will just cool down in a lap or so. And rain tires like to run well under 150F.
     

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  18. ilikebass

    ilikebass Active Member

    Thanks for the reply. But I do not see how my question is over complicating anything. Keeping heat in the tires is of paramount importance, so in addition to going out hard immediately off the warmers to keep them hot, if changing pressures can help keep temp in them that should be part of our intellectual toolbox shouldn't it? As I said, I thought that dropping pressures helps generate more heat (and so did Crafar apparently) but it sounds like it's actually higher pressures that generate more heat. I was thinking I could run the high end and the low end of pressures for 10 laps back to back and check with a thermal gauge to see which setting results in higher tire temps. I understand this only gives surface temp not temp in the carcass. Not seeing how understanding this heat generation thing is over complicating anything. Seems like it would be a useful piece of information to have for those of us who ride the track in the cold. A few weeks ago at the track the ambient temps during the day were 40-55 F, I will spend all of next week at the track also and it is projected to be about the same.
     
  19. Blue Junk

    Blue Junk Well-Known Member

    You’re not the only one that thought/thinks that about pressure and temps.
    I’d say the most important thing to keep in mind is that the tire needs to be in its temp range. The data your collecting is only relative to you and your ability to generate temp in the tires.
    Tire stuff isn’t rocket science but people sure know how to F it up properly in quick order, then argue about it endlessly...
    Good luck. Report your findings if you’re interested. There’s a wealth of knowledge here. Most don’t open their mouth much though, they’re watching though.
     
  20. Pneumatico Delle Vittorie

    Pneumatico Delle Vittorie Retired "Tire" Guy

    The first thing to do off the track is to check hot psi because checking hot psi is more accurate than checking tire temps. As I’ve said before on this thread (post #64) checking temps isn’t going to tell you much. And the reason it’s almost impossible to do the exact same thing on track or exiting it to be able to see get usable data. But if you want usable/repeatable tire temp info put 3 infrared sensors on the front fender and 5 sensors on the rear hugger and then look at tire temps from the on track sessions.

    And with all due respect do what you want and go ahead and probe away. But don’t forget to use that thermometer to check the warmers as we have seen low output from a generator or even a land line keeping the warmers from getting up to at least 176f.

    For any situation the same process applies, monitor the hot psi and try to keep about a 2 psi rise off the track. In cold weather compound choice is extremely important, so if it's brutally cold a SC2 rear may be better than a SC1. And if you use a SC0 you’ll probably cold- tear the crap out of it. Pirelli front tires as much less sensitive so a SC1 will be the best choice. To select the correct compound for the conditions look at the first post in this thread and review the chart. And remember there is no magical way (either psi or trying to tune your tires with a temp gauge) to get them up really hot when the conditions aren't optimal.
     

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