Cold Tire Crash?

[mpusch]

I had a blast this past weekend at Pittrace, it's just unfortunate I ended the last session of the weekend with my first ever crash. I'm trying to move past it as quickly as possible, but I want to make sure I understand why it happened so I can at least learn from it and have some confidence moving forward.

I've run PP3s for most of my riding career, and never had a problem with them on track (mid-intermediate). However, I wanted to try something different and try the Pirelli Superbike Pros, since they seem to be pretty much geared towards me. The big thing is they are supposed to be able to be used without warmers.

Here's a video of my first couple turns on the tires. Had pressures at 31F/26F per recommendations, and I was really trying to take it easy on the tires. This was the last session of the day, and the track was just about bone dry. Notice I take both of the lefts on sealer and at a slightly more demanding pace than my first right hander. Any thoughts?

 

[adotjdot]

Hey Micah, hopefully you are ok from the crash. Knowing what happened is the first step to getting past the crash. Quick question, from the video I can hear you are backing off on the throttle, were you also using the brake when you went down?

Without more data, my best guess would be yes, cold tires. That is a quick transition from left to right and even at a lower pace than your previous turns, if you are adding too much lean and brakes on a cold tire too quickly, you are asking the tire to do too much which causes it to wash out. The left turn leading into that section you are building brake pressure straight up and down then gradually giving it away without much lean, so you are not asking as much from the tire.

And something to note about tires in general. All tires, regardless of brand and type, do not NEED tire warmers. Warmers are just used to bring the tire up to operating temp so that the rider does not need to build as much heat into them on the track before aggressive riding. So even with slicks, you do not need to run warmers, you will just need to spend a longer time building heat into them before you can ride aggressively. To properly build heat into your tire, get the bike straight up and down, accelerate hard, and brake hard. Again, only straight up and down! Make sure you give yourself at least a half a lap or more to build that heat before adding aggressive inputs into the corners.

 

[Otto Man]

Had no idea that was you that crashed. I'm not very good at putting forum names to people once I see them at the track. Your bike did a nice job at spreading various parts across the track...thankfully, CR Manix did what he should have done and put a hand up as soon as he saw your bike. I was behind him and could not see the crash, so him putting a hand up gave me that much sooner of a heads up to get ready. Kudos to you also for doing the right thing and immediately getting off the track and out of the impact zone. As far as the crash...

Lots of variables, but my .02 cents: The last session of the second day is always a blast, as it thins out from people packing up early to go home. It's also the time where some of the biggest crashes happen, typically from people riding every session both days, and you get fatigued and get lazy on your riding. Maybe you were muscling the bars too much and not turning the bike enough with your legs/weighting the foot peg. Very easy to over load the bars that way and not allow you to feel the feed back the bike is giving. Another thing was the weather - there was that massive rain front moving in, and right when the session started, the temperature dropped quite a bit. Colder pavement = less grip.

Those tires don't need warmers, true - but they (and any other tire) still need time to warm up. Simply going down the one straight into one braking zone with a quick little left hander isn't enough to get that tire up to optimal, ideal operating temperature. I think you got lucky from the left hander because you didn't start descending into the bowl, so there wasn't a whole lot of load on the front end of the bike. That first right hander really starts to load the front end, especially once you start carrying more speed and you're still braking from the first left hand turn.

So there we have multiple factors in play - colder pavement, cold tire...and the final thing was the sealer. That sealer just doesn't provide the grip that the rest of the track has - very obvious by your video, you slid on the sealer, then the tire catches traction as soon as you get off the sealer. I tried showing a number of riders the line in the bowl itself, which is basically riding the left side of the track all the way around, completely avoiding the sealer. Even on Saturday, with rain tires, avoiding the sealer was the fastest way around the track.

I don't believe it's the tires at all - the gentleman in front of you at the beginning of your video runs the exact same tires. I've worked with him on a number of occasions.

 

[mpusch]

Thank you both for the input. I think I'm pretty good as far as injuries go. My lower back is sore (had a back protector on, but apparently not a long enough one...that'll change), but that's about it.

I agree that several of variables listed above are elements that contributed to it. I understand the fatigue element, but I had taken session 6 off (switching tires) and I really felt 100% out there.

I can't remember specifically if I was on the brakes there. I thought it sounded like my RPMs were holding steady, indicating maintenance throttle...perhaps. I know I commonly would trail slightly (3-5%) through there sometimes.

I guess you guys boiled it down pretty good. I don't run warmers on the PP3s so I'm used to running a lap or so off pace, and thought running 70% speed through there with a slick would have been enough. It might have been, if the conditions were a bit warmer and I didn't run the sealer. For what it's worth, I ran just about all weekend off the sealer as much as possible (including the bowl), but thought that when it dried out it wouldn't have been an issue.

Lesson learned, and I'll have the PP3s back on next time if I have any concerns about weather. And if I do run the Pros, I'll have warmers on them just to provide that extra margin.

 

[adotjdot]

Glad you are ok!

 

[D-Zum]

PP3s, Slicks, DOT's, etc.....maybe it's just time for warmers and the peace of mind they'll offer you.


I have an extra set of Suzuka's that have been used for 3 days I'll sell ya cheap. PM me if you're interested. I bought them some years ago
because I went to Atlanta and left my Chicken Hawk's in the garage. The tire vendor there had warmers for sale. I've kept them around
as spares.

 

[HavocCat]

It's very interesting to see your back tire just slip out like that without any (what sounds like anyways) throttle.

I'm glad you are ok, each crash is a learning experience! Get that baby back together for June!

 

[Motofun352]

First..videos can be deceiving...having said that, in the dry I would take a wider entrance into that turn and run across the sealer before the apex. The wet sealer just plain sucks but in the dry it's not as bad as it looks. Glad you're OK.

 

[mpusch]

First..videos can be deceiving...having said that, in the dry I would take a wider entrance into that turn and run across the sealer before the apex. The wet sealer just plain sucks but in the dry it's not as bad as it looks. Glad you're OK.

That's why I was kind of confused. I avoid sealer like the plague in the wet. But in the dry it should be decent, right? Had no problems with the pp3s on them in the dry. I wouldn't think slicks would act any worse than hypersports on it. But if the temps weren't up in brand new tires, that might have been the 2% difference.

Thanks Chris, parts get ordered tomorrow. Not too long of a list fortunately. Just not sure if the tank will make it or not...

PM on its way D-Zum.

 

[Dave561]

We should throw a camera in the middle of every corner like that. Really great angle for on coming bikes.

Sucks hitting the ground, the guys pretty much covered it, but I am honestly a little confused as there seems to nothing obvious in the video. Not being there though I don't have any idea what the grip level was in that corner.

 

[Greg ZX6R]

I'd be interested in seeing the ideal operating temperatures for the tires you were using. I remember an article in RRW a few years ago regarding the operating temps for Michelin DOT/slicks versus their street tires. Both had the nearly the same upper temp. limits, though the street tires (Pilot Power or PP3's) had a beginning operating temp. (i.e., they started "working") that was 50 degrees lower than the DOT/slicks. If I remember, the street tires started "working" at 102 degrees, and the DOT's/slicks started at 152 degrees.

 

[prplppleatr239]

I was behind and caught some of the crash and barrel roll on camera.

 

[mpusch]

We should throw a camera in the middle of every corner like that. Really great angle for on coming bikes.

Sucks hitting the ground, the guys pretty much covered it, but I am honestly a little confused as there seems to nothing obvious in the video. Not being there though I don't have any idea what the grip level was in that corner.

Seemed fine most of the day

I'd be interested in seeing the ideal operating temperatures for the tires you were using. I remember an article in RRW a few years ago regarding the operating temps for Michelin DOT/slicks versus their street tires. Both had the nearly the same upper temp. limits, though the street tires (Pilot Power or PP3's) had a beginning operating temp. (i.e., they started "working") that was 50 degrees lower than the DOT/slicks. If I remember, the street tires started "working" at 102 degrees, and the DOT's/slicks started at 152 degrees.

Makes sense. I think the SBK Pros are supposed to come in a bit earlier than slicks, but really that makes sense. I mounted and balanced my own tires (have been for a year or so), but can't think of anything I could have done to cause that from a mechanical error perspective.

I was behind and caught some of the crash and barrel roll on camera.

Thanks! I was wondering if anyone else caught it.

 

[raineman021]

Mpusch - It seemed as though you had taken T3 on the left side of the tires and held up fine (even with the sealer) while possibly even asking more of the tires there than in T4 (*arguable*).. Which makes it odd to see such a loss of traction on the rear leaning/trail braking to the right in T4. Not sure if going down hill there changes that at all -- OR maybe there was something on the tire itself on the right side that you picked up while motoring through the paddock (I would like to think that is not the case).

Regardless of the true verdict - I am glad you are ok man! Definitely grab some tire warmers to rule out that possibility. I plan to do the same, haha.

 

[vinny337]

Mpusch, Get yourself some warmers and check your tire pressure before every session. Although I didn't need them, believe it or not I used warmers when I was in "B" group…mainly for the confidence level.

 

[mpusch]

Darrin hooked me up with a set! Have no desire to do that again...

 

[physicistkev]

Didn't read this above so I wanted to mention it. You put your rear tire on the inside of the seam for the asphalt patch. Cold tires will have an effect, but so will an uneven patch of pavement. Don't put 100% on the cold tires, I think the seam played more than a minor part.

 

[mpusch]

Didn't read this above so I wanted to mention it. You put your rear tire on the inside of the seam for the asphalt patch. Cold tires will have an effect, but so will an uneven patch of pavement. Don't put 100% on the cold tires, I think the seam played more than a minor part.

Interesting thought...I kind of did that in the first half of the corner too though right? Makes sense that it would reduce contact patch.

 

[physicistkev]

I mention this as there is a seam at Barber, on the exit of turn 5 that got me out of the seat once. That was 3 laps in and I was using warmers. At 4:19 or so.

As soon as I ran over the seam, that's when the rear started to catch up with the front.

 

[mpusch]

I mention this as there is a seam at Barber, on the exit of turn 5 that got me out of the seat once. That was 3 laps in and I was using warmers. At 4:19 or so.

As soon as I ran over the seam, that's when the rear started to catch up with the front.

Wow. Yeah screw that crap. Consider me advised!