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What's causing my Pirelli SC2 tire wear pattern issue?

Discussion in 'Tech' started by DmanSlam, Mar 6, 2021.

  1. Wheel Bearing

    Wheel Bearing Professional low sider

    Manufacture also doesn't recommend modifying your engine/electronics...so...
     
    TurboBlew likes this.
  2. RandomTask

    RandomTask Well-Known Member

    So...apples and oranges. If you mod your engine/exhaust/electronics and it fails, it’s unlikely to throw you off the bike. A tire failure is more likely to do that. If we want to play whataboutism and go to extremes.

    I’m not drawing a line in the sand based on what the manufacturer says. My opinion is that the design intent of an item should inform, not direct, the decision making process. An ECU, flash, exhaust, etc is purpose-built. Flipping a tire intended to run in one direction is not.

    Didn’t want to ruffle anyone’s feathers, just want to ensure we don’t confuse opinions from objective facts.

    If you want to flip your non-bidirectional tires, by all means. Just don’t pretend it’s risk-free.

    /end_thread_jack
     
  3. TurboBlew

    TurboBlew Registers Abusers

    and strongly recommends a qualified service center... then I watched a guy crash his brains out because a dealer serviced his forks to OEM specifications leaving about 30mm of the fork leg unused and the preload ranked to 11. You could feel the forks hit the mech bottom of the stroke just putting weight on it. But the tire told the tale of how overloaded it got.
     
  4. Wheel Bearing

    Wheel Bearing Professional low sider

    Is running Pirelli's for 8+ years and having flipped literally every single rear tire during that period (at least once, sometimes 2 or 3 times) without the slightest hint of a tire carcass integrity issue an extreme case too? Oh, and also not personally knowing (or even reading on the internet) about a Pirelli tire failing because it was flipped as well?

    Flashing the ECU is not the manufactures purpose built function. Apples to apples.
     
    TurboBlew likes this.
  5. RandomTask

    RandomTask Well-Known Member

    Good for you


    Sent from my iPhone using Tapatalk
     
  6. 2blueYam

    2blueYam Track Day Addict

    Yeah, in my original reply I did state my experience is on an old 1000 and SC2 rear (with about 140HP, but over 70lb-ft of torque) and may not apply to his 600. Agree on turn 9, as I was gently rolling on the throttle typically before apex on that one, but if I gave it too much too soon, even as I was picking the bike up and it would spin up and wear the shoulder.

    The going wide thing was more on just on turn 2. My issue there was picking the bike up earlier so I could add more throttle, and the bike would of course run wider (duh). Unfortunately, that was eating up the shoulder of the tire because I had to keep a decent amount of lean angle to get over for a good line for turn 3. My fix was to keep the bike down to the apex in 2. This meant less throttle at that point, but after that, I could pick the bike up more, have a shorter path to turn 3, roll into the throttle a bit faster with less resulting tire wear on the shoulder. It is a tiny bit slower, but a lot less tire wear on the shoulder.
     
  7. stangmx13

    stangmx13 Well-Known Member

    The rule of thumb is roll on when you are able to get to WOT smoothly and quickly. For me, I try to get to WOT in 1-1.5sec. If it took longer than that, I may have rolled on too soon. If I can do it quicker than that, I definitely rolled on too late.
     
  8. DmanSlam

    DmanSlam Well-Known Member

    So...The long, throttle roll-on seems to suggest your corner speed was too high and the line was too wide, having to wait till you can get to WOT? In the short roll-on, corner speed too slow resulting in, apparently, a tighter/straighter line, allowing you to overcompensate with the throttle?
     
  9. DmanSlam

    DmanSlam Well-Known Member

    I'm definitely going to remember this because, yes, passing under the bridge and the dip following it, required making a 'decision' on getting the pass done vs looking reckless, spooking a slower rider, crashing, contact or the rider resisting the pass. :) Feels good when you get it done though. Breathe, wiggle fingers and roll back on the throttle...
     
  10. stangmx13

    stangmx13 Well-Known Member

    There can be many causes of your roll on not matching the corner. The ones you listed can be true.

    I think its important to understand why an early roll on is a bad idea. Acceleration increases your turning radius. If you roll on early, the outside edge of the track starts getting closer. You notice and slow or pause roll on so that you can finish the corner without running into the dirt. Having too much corner speed or a wide line makes this even worse! But it's all the same problem.

    A little off topic here... I do think that whacking the throttle open and tearing tires is 2-3 issues wrapped into one crappy outcome. Their apex speed is low. The edge of the tire doesn't see much load and the whole tire is colder than it wants to be. They're also late with the throttle so the tire has less time generating heat. Then they get on the throttle. The cold carcass doesn't flex enough to handle the load and tears the surface off. On top of all of that, we are probably talking about a newer rider with a less-than-ideal setup, which makes everything even harder on the tire. Poor tire.
     
    MachineR1, DmanSlam and TurboBlew like this.
  11. DmanSlam

    DmanSlam Well-Known Member

    Can't refute that statement --> I do think that whacking the throttle open and tearing tires is 2-3 issues wrapped into one crappy outcome. I "think" I'm rolling the throttle on very quickly but I definitely have 2 issues, minimum, after reading everyone's comments. Appreciate them all.
     
  12. DmanSlam

    DmanSlam Well-Known Member

    After watching this video -- I found this video of two guys (they're brothers) riding on Summit Point Main -- I'm back for follow-on discussion about throttle application in mid-corner.

    I mentioned, while riding on slicks, I'm on the throttle pretty fast and, sometimes, pretty hard...because I can. Related to my technique are video segments for comparison. Is this the example to follow or can even they do better?

    At 0:20 and, again, at 3:18 -- turn 1 entry and throttle roll-on technique. Their throttle roll-on happens where mine does, sometimes a cracked throttle before the apex as well. Too slow, too fast or just about right?

    At 2:55 -- downshift occurs at pit entry heading into turn 10. That's well beyond the overpass and almost beyond the downhill section. I NEVER downshift this late. Is that a slipper clutch kicking in or do I need to work on my braking point? I'm comfy with the turn-in and apex. My knee is down consistently...not that it means I'm going fast through that turn.

     
  13. JCW

    JCW Well-Known Member

    I think last night I saw some videos of Brandon Paasch and Greg Melka at Summit Point... their videos might be worth watching. The one above has a real fisheye lens distortion to it.
     
  14. Pneumatico Delle Vittorie

    Pneumatico Delle Vittorie Retired "Tire" Guy

    Mr. DSlamMan I think MAYBE it's time for you to do a school with a well known racer with one on one instruction. In the long run this will probably help you more than Jimmy and Joey BBS offering their opinions, and maybe cost less too. Just my 2 pennies worth
     
    DmanSlam likes this.
  15. stangmx13

    stangmx13 Well-Known Member

    Those did not look like good clean laps. It looked like they were messing around.
     
  16. DmanSlam

    DmanSlam Well-Known Member

  17. mpusch

    mpusch Well-Known Member

    Nothing against these guys at all, but I see no reason to use them as a benchmark for anything. In addition to that fish eye effect making it almost useless for any comparison, they are running about 130% off the lap record pace there.
     
    DmanSlam likes this.
  18. DmanSlam

    DmanSlam Well-Known Member

    Haha. The 360-camera does distort the video a bit. I will look at some other actual race videos for this track, and others, that I ride at.
     
  19. 2blueYam

    2blueYam Track Day Addict

    You can start with this gem with three of the fastest 600 riders that have ridden Summit Main:
    Summit Point Main - On Board R6 - YouTube
     
  20. DmanSlam

    DmanSlam Well-Known Member

    You know that was a cool-down video, right? But it's a good lead on riders to watch. I have seen Paasch's videos long before he won Daytona.

    I know Xavier a bit as he's a regular at the minimoto track. I didn't know much about him at the time though. Just that he raced.

    True story at the kart track (not that I make things up):

    Xavier broke a master chain link on his 300/400, I don't recall the bike exactly. I called around to friends nearby to see if they had a spare. But Xavier's chain size was a 417 or some weird size. No luck. So, he sat with a busted bike while Emerson/Bobblehead and their third buddy rode. I offered to let him ride my TTR125. He flat-out turned that offer down. But then, I said, Okay, how about my Ohvale 190? He jumped on that offer immediately. Lol. I was still getting used to riding it anyway and figured Xavier might like the GP style and horsepower.

    Well, that is when I learned who he was and, also, I learned what my Ohvale is capable of doing. He was keeping pace with Emerson on his 300/400 on the kart track, backing it in, wheelies. Shredded the last bit of life out of my rear tire. I let him ride it the entire time he was there. Cool thing is that he actually paid me some money for expenses -- although it wasn't enough to cover that rear tire replacement. Lol. He also critiqued the settings on my bike that made a big difference since he and I were about the same weight.

    Watching Xavier on my Ohvale that day? Seeing is believing.
     

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