Important warning!!!

stkr00

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I'm not sure if this is what caused my problem or not, but it's worth a warning to those that ride the track, or other high speed "areas". Sorry for the length, but you need to have the image of the day to get the full effect.

I attended the Learning Curves Racing license school yesterday at Road America (4/21). After already completing two full NESBA days at Road America and getting bumped to Intermediate, I was very confident in my abilities there compared to those in the class that had not ridden the track before.

Woke up early, took a shower, got the bike ready, and everything was going perfect as the sun was coming up. Finally found the LCR pit area, got in class, everyone is pumped up because it is a beautiful day. First class session is over and we're getting ready for our first practice session.

I check the tire pressure. Front 31 -check, Rear 25 -hmmm? I roll the bike over to get some air from a neighboring pit...nice guys from New Jersey. Rear 30 -check. Cool, now I'm ready to rock. First call for LCR...gear on, bike started, off the stand, and out to Pit-In.

We go out for our snail pace lap to show the new guys the track. No biggie...it's a beautiful 4 mile scenic trip. 2nd lap, Rick is waving us by two at a time. I get my wave on the carousel and motor around...remembering I don't have a lot of heat in my tires yet. I take it easy until I get back to turn 1, and then it's GAME ON. I pass one rider going into T-3, then another two down the straight to T-5. Now...this is where it all goes wrong...

Breaking hard and downshift for T-5, lean it in, a little squirmy...hmmm, roll on to drive out...REALLY squirmy...thinking maybe I picked up some sand or ran through something. I take it a little easier into T-6 but now it's even worse...can barely steer the bike out of the turn. My hand comes up and I'm riding the edge of the track at about 30mph trying to figure this shid out. I do the next 2 miles of the track at about 15 mph waving anyone behind me by hoping I don't get rammed by another student.

I finally get back to the pits, and up on the rear stand. Gloves get thrown into the tent as well as the jacket and back protector. The Arai got gently placed in the chair.

My rear tire is completely flat...not one bit of air. You can almost push the tread all the way to the rim. The tire was so hot you could hardley touch it. I'm pissed. Get the tire off and go to get a new one. Dunlop brought the wrong tires due to a sticker error. Michellin has a tire...cool. Power Race - Medium/Soft :cool

I go back to class...fuckin tight schedule. Get out of class, pick up my tire. The guy didn't look for a puncture. The tire was scorched anyway. Get the tire back on the bike. Check the pressure - 22 psi...good to go. That's when I notice my valve stem cap from the original tire sitting next to my stand. This had no meening until later...

Later on I realized that the only reason the original stem cap was there, was because I had NOT put it back on after getting the first tire some more air. I never removed it after the flat, because I new there wasn't any pressure in the tire.

The centrifugal force at the high speeds of the track were "probably" enough to pull the valve core in, and therefore, allowed the air in the my tire to escape because I DID NOT have the o-ring valve cap on as required by tech. It was on when I went through tech, so it is not their fault. It is my fault for allowing myself to get in a hurry and overlook a simple detail that could have had a far worse outcome than just the cost of a new tire.

I'm almost ashamed to admit all of this, but hopefully it will help prevent anyone else from experiencing this same ordeal.

PLEASE: Check you caps, and make sure they're on and tight.

BTW...The Michellin Power Race tires...
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Man, glad your ok and everything worked out. Thanks for the heads up.
 
"o-ring valve cap on as required by tech" can you tell me what that is? is it just blk palstic valve cap or something else?
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Wow ... great story and a good lesson for us to remember. Thanks for sharing. Glad neither you nor the bike were hurt.
 
Stkr00, so many times that stories that start like yours end much much worse. Glad your ok bro.

Don
 
Thanks for sharing that....thats good stuff know about....glad nothing worse happened
 
I'm not sure if this is what caused my problem or not, but it's worth a warning to those that ride the track, or other high speed "areas".  Sorry for the length, but you need to have the image of the day to get the full effect.

I attended the Learning Curves Racing license school yesterday at Road America (4/21).  After already completing two full NESBA days at Road America and getting bumped to Intermediate, I was very confident in my abilities there compared to those in the class that had not ridden the track before.

Woke up early, took a shower, got the bike ready, and everything was going perfect as the sun was coming up.  Finally found the LCR pit area, got in class, everyone is pumped up because it is a beautiful day.  First class session is over and we're getting ready for our first practice session.

I check the tire pressure.  Front 31 -check, Rear 25 -hmmm?  I roll the bike over to get some air from a neighboring pit...nice guys from New Jersey.  Rear 30 -check.  Cool, now I'm ready to rock.  First call for LCR...gear on, bike started, off the stand, and out to Pit-In.

We go out for our snail pace lap to show the new guys the track.  No biggie...it's a beautiful 4 mile scenic trip.  2nd lap, Rick is waving us by two at a time.  I get my wave on the carousel and motor around...remembering I don't have a lot of heat in my tires yet.  I take it easy until I get back to turn 1, and then it's GAME ON.  I pass one rider going into T-3, then another two down the straight to T-5.  Now...this is where it all goes wrong...

Breaking hard and downshift for T-5, lean it in, a little squirmy...hmmm, roll on to drive out...REALLY squirmy...thinking maybe I picked up some sand or ran through something.  I take it a little easier into T-6 but now it's even worse...can barely steer the bike out of the turn.  My hand comes up and I'm riding the edge of the track at about 30mph trying to figure this shid out.  I do the next 2 miles of the track at about 15 mph waving anyone behind me by hoping I don't get rammed by another student.

I finally get back to the pits, and up on the rear stand.  Gloves get thrown into the tent as well as the jacket and back protector.  The Arai got gently placed in the chair.

My rear tire is completely flat...not one bit of air.  You can almost push the tread all the way to the rim.  The tire was so hot you could hardley touch it.  I'm pissed.  Get the tire off and go to get a new one.  Dunlop brought the wrong tires due to a sticker error.  Michellin has a tire...cool.  Power Race - Medium/Soft :cool

I go back to class...fuckin tight schedule.  Get out of class, pick up my tire.  The guy didn't look for a puncture.  The tire was scorched anyway.  Get the tire back on the bike.  Check the pressure - 22 psi...good to go.  That's when I notice my valve stem cap from the original tire sitting next to my stand.  This had no meening until later...

Later on I realized that the only reason the original stem cap was there, was because I had NOT put it back on after getting the first tire some more air.  I never removed it after the flat, because I new there wasn't any pressure in the tire.

The centrifugal force at the high speeds of the track were "probably" enough to pull the valve core in, and therefore, allowed the air in the my tire to escape because I DID NOT have the o-ring valve cap on as required by tech.  It was on when I went through tech, so it is not their fault.  It is my fault for allowing myself to get in a hurry and overlook a simple detail that could have had a far worse outcome than just the cost of a new tire.

I'm almost ashamed to admit all of this, but hopefully it will help prevent anyone else from experiencing this same ordeal.

PLEASE:  Check you caps, and make sure they're on and tight.

BTW...The Michellin Power Race tires...  
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uhem...just so I don't seem like a condescending jerk here...let me point out a few things that's just don't register correct with me here...and maybe someone can enlighten me..or?...(and what concerns me here)...maybe it was "something else" that caused this situation....as follows...

First?...

"I'm not sure if this is what caused my problem or not, but.."

well written...

2ndly?..wtf is this all about..

"Front 31 -check, Rear 25 -hmmm? I roll the bike over to get some air from a neighboring pit...nice guys from New Jersey. Rear 30 -check."

but then 5 paragraphs later?...

" Get the tire back on the bike. Check the pressure - 22 psi...good to go."

please tell me there's a numerical typo somewhere's in there and...

Lastly?....

"The centrifugal force at the high speeds of the track were "probably" enough to pull the valve core in, and therefore, allowed the air in the my tire to escape"

"Centrifugal Force" would never pull a valve core "INWARD"...as centrifugal force always throws things "OUTWARD" from center.

Now here's a "Far More Likely" scenario of what really happened...

Like many other track day junkies you followed suit and thought it a great idea to run lowered air pressure in your tires..except when you lowered that air pressure do to the 30lbs range?...there are mold seams left over from manufacturing of the tires that run right across the sealing bead of those tires...the manufacturers know this but also know that provided the owner/consumer runs anywhere's near the manufacturers recommended air pressure that those mold seams will seal up and the soft compound will yeild an air tight bead/rim seal just fine...but then here comes john q. racer who knows better and knocks 6-10 lbs off the manufactures suggested air pressure cause he just knows he'll get better traction and a bigger footprint through the curves...but what he doesn't know is this...

I watched my Metzeler mez4 rear off my FZ1 blow tiny soapy bubbles out of each and every one of those bead wall mold seam right up until about 32lbs psi...and then?..they all sealed up fine...and then I ran 38-40lbs thoughout the life of that tire just fine.

STKR..Here's what more than likely happened to you..

You dropped your air pressure for your track session the night before..causing the rear to develope a slow leak at the bead wall seams..you caught it by measuring 25lbs and corrected to 30...and then?..hit your first few curves...and as the tire deformed rolling about it's own footprint?..it put just a slight strain on the sidwall to allow more than just a slow leak...and when it was "Game On"?...and you came blasting into that first curve?..."THAT"....is exactly where and when you lost a lot more pressure big time...I've seen lose valve stems cause leakage....but never, ever, due to a valve stem cap being left off.

L8R. Bill.
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Jinkster...did you stay at a Holiday Inn Express Last Night
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Good Info bro, well thought out, and makes complete sense...Not sure if it is correct, as it is way above my head, but very good info.
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("Centrifugal Force" would never pull a valve core "INWARD"...as centrifugal force always throws things "OUTWARD" from center.)But the valve core would be moving outward, I don't think the force would overcome the spring though. Sounds like one for mythbusters
 
Jinkster...not a typo...just left out some details.

Front tire: Dunlop 208GPA Race DOT, 31psi per Dunlop for the track.

Rear Tire (Original): Dunlop 208GP-JLB Race DOT, 30psi per Dunlop for the track.

Rear Tire (Final): Michellin Power Race, 22psi per Michellin for the track.

If you want to let air out of your tires, you push the center core in TOWARDS the outside of the tire (tread area) and NOT in towards the axle area. Centrifugal force WILL act on this core, and if the resultant centrifugal force due to the mass of the core is greater than the tension spring holding it shut, it will open up.

The valve stems are metal with mith metal valve caps with sealing o-rings. Required by the CCS rulebook. Tech is the inspection area you have to pass before they allow you on the track.


Sorry I created such a shitstorm here. I guess next time, everyone can just figure it out on their own. Good luck...hope I'm completely wrong and you can all remove your valve caps and do top speed runs with complete confidence.
 
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