Front tire wear...just another tire wear question.

Discussion in 'Performance & Technical' started by guidout, May 9, 2017.

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  1. guidout

    guidout Rides with no training wheels

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    hi all,
    I have been at my first race weekend at Grattan this past weekend.
    It was a blast...

    On Sunday morning I put a new set of Pirelli Sc1 on.
    I did 2 practice sessions and 4 sprint races with them.
    Air temperature was between 45 and 55 throughout the day.
    Tire pressure hot:
    35/29 in the morning
    35/27 in the afternoon

    I never got this king of wear on my front tires.
    From my previous experience and doing some more research I cannot recognize this kind of pattern...I don't think it is cold tear. It might be a light hot tear.
    What about suspension setup?
    As side note, I was running between high 1:24s and mid 1:26s

    Any input is always appreciated.
    Thank you

    [​IMG]
    [​IMG]
     
    #1 guidout, May 9, 2017
    Last edited: May 9, 2017
  2. indy

    indy What's an apex?

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  3. guidout

    guidout Rides with no training wheels

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    well, it looks like I was right on the high end of the range. The day was pretty cool...maybe it warmed up and I didn't do a good job at tracking tire pressure.
    Still I would like to understand the tear pattern. I've looked a lot on the internet but can't find a similar pattern associated to a specific issue...
     
  4. Scarpino

    Scarpino It's Smiles per Gallon......

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    Watch "2 Clicks Out" with Dave Moss on Youtube. You would be surprised what you can learn. He has a ton of trackside videos about suspension set-up, Suspension vs wear, Pressures vs wear, and how to read tire wear.


    Here is an older video...but a great example of what you will find on his channel.

     
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  5. indy

    indy What's an apex?

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    It looks like the tire was warm and the track wasn't fresh as in great asphalt. IMO
    That's a good pace for that track, at your pressure and the tires warming up plus the track being not being smooth could cause some scrubbing.
    I think your pressure was a little high. So cold tearing.
    But I'm also feeling out the pressures and suspension settings. Hopefully one of the tire guru's will chime in.
     
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  6. Dave608

    Dave608 Let's Ride!
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    I'm thinking pressure issue but I sent the pic to someone who should know the answer. Important question, you say 35 PSI which is fine, do you know for sure if your gauge is correct?
     
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  7. guidout

    guidout Rides with no training wheels

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    I compared my pressure gauge with people having much nicer ones and it measures the same, but I don't think it's a good way to assess accuracy.
     
  8. Dave608

    Dave608 Let's Ride!
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    Well, it's definitely better than nothing for sure. I always compare mine with the tire vendor since that is the one he is quoting on pressure recommendations, actually down south the Pirelli vendor carries a Dill gauge calibration station with him just for testing purposes.

    Anyway, the response I got back is that it definitely looks like a pressure problem assuming you have never had that issue before at that track (he said it could be geometry related as well but if you haven't changed anything probably pressure). Given the track temp was probably cool given the air temps you quoted you might have needed to run a little lower pressure for more flex to build more heat in the tire. Only way to really know 100% is to take tire temps on hot pit right as you come in from a hot lap.
     
  9. guidout

    guidout Rides with no training wheels

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    That's great. Thank you very much for taking the time to ask around.
    I'll do a better job at tracking the tire temp/pressure.
    I have been planning on buying a temp gun for quite long time...I'm they are pretty cheap so it was mainly me being lazy and/or forgetting. But I also always wondered about their accuracy? Do you use/recommend them to measure tire temps? If so, do you have a suggestion on brand?

    Thanks again,
    Guido
     
  10. Scarpino

    Scarpino It's Smiles per Gallon......

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    I purchased one from Harbor Freight for about 15 bucks.
    Its cheap, but not 1000% perfect for the readings your trying to achieve, but it gives an idea of what temps your tires are at.

    The reason why they are not exact (my reasoning) is because when you come off track.....drive to your pit.....hop off the bike, put it on the stands, pull your helmet off, etc.....how many degree's have you lost? Its an unknown equation.. a.nd the equation would have so many variables due to weather, track temps vs pit temps, if you remove any gear before you check temps, remove all your gear and then check..so on and so forth,.... So I just use that reading as a reference or guide...

    Maybe someone else will chime in with a more detail...
     
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  11. Dave608

    Dave608 Let's Ride!
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    While the IR guns are ok they are only getting surface temp, best is a tire pyrometer. I don't have one yet as if I'm at a race weekend my tire vendor has one and will work with me. For trackdays I have enough experience to generally hit pressures pretty close.
     
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  12. skidooboy

    skidooboy titainum plate tester

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    Common tearing with the Pirelli SC1 at grattan, once you break 1:27ish laptimes (in my experience). I chase the same thing with sc1. if I go to the sc2, it goes away. tires are consumables, if you weren't on your head, and you were close to your personal best, ride it, and replace the tires for the next race weekend. they will be good take off's, or track day tires. Ski
     
  13. guidout

    guidout Rides with no training wheels

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    wow if that happens when lapping in the 1:24s/1:25s, I wonder what will happens when I'll get in the 1:22s...and I will one day...:)
    I agree with you, the more speed you pick up and more you destroy your tire (dammit), but on the other hand, I'm a strong believer that the tire tells a lot, I just never saw that specific pattern especially in the front. I got pretty good at making adjustments for weird rear wear but the front is still an unexplored territory for me.
    On a side note, I love michelin slicks, but the SC1 in colder temps are really awesome.
     
  14. skidooboy

    skidooboy titainum plate tester

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    there's where your problem may lie... sc2 for colder temps, sc1 for mid to warmer temps, sc0 for hot temps. Ski
     
  15. guidout

    guidout Rides with no training wheels

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    oh ok...still learning lol
    speaking of tires, they have an arrow indicating the rotation direction, can I flip them or it's not recommended?
     
  16. steve p

    steve p What's an apex?
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    Classic Grattan tire tear. Not pressure. For sure compound and or geometry, along with springs. It doesn't happen until you hit the 24/25 ish pace. What springs do you have in your forks? Where are your forks in relation to the triple?
     
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  17. guidout

    guidout Rides with no training wheels

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    sorry, I was out for the weekend.
    About your questions, not sure about the spring specifically. I have k-tech internals and the spring is has been chosen for a 165lbs rider (the previous owner). I am a bit heavier, 185lbs, so the springs might be a bit off. Of course I re-tuned the suspensions for me and I love them...
    The forks are in the stock configuration with respect the triple clamp.
    It's good to know that at least I was in the ballpark with pressure.
     
  18. Leo Mendonca

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    Hello guidout, did you find out what the probem was?
    Back in Brazil I had the same problem with SC1 in the front. Because of my riding style I break deep towards the corner, release the breaks, coast until feel confident and then I get back to acceleration. doesnt matter the tyre pressure for me, I always had the same problem. in fact the in my last try i put 35hot and I was afraid to go further than that. the result was just a little worse than your second picture. Unfortunately in Brazil they dont sell SC2 for the front... So I tried many suspension setups and realized that the tire wasnt adequate for my riding style. I needed something harder which unfortunately I woudnt be able to buy,,, rsrsrsrs or Id have to change my riding style and adapt myself to that situation...
    maybe if you unlocked the secret you could share with me. thanks
     

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