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Discussion Starter · #1 ·
Top ten signs you are not going to finish a turn on two wheels...



Other than the fact as was running a bit too tight a line for the speed at which I was taking the turn, I am still surprised that the rear let go the way it did. I was just steady on the gas, preparing to pick the bike up after hitting my apex, and boom! It let go without a warning. Was running a 180 Pilot Power with 38 lbs of pressure. I had taken that same turn many times without a problem, but this time the tire decided that it had had enough.

I consider myself fortunate to have been able to keep the throttle on (notice the black stripe) to avoid what could have been a pretty bad highside I suppose. No damage other than a snapped left slider, a broken mirror, twisted clutch handle and minor scratches which will be fixed easily.

It would be a much better learning experience if only I knew why the hell the back end broke loose...
 
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Discussion Starter · #2 ·
Re: You Know You Are Not Making It When... Image Worth 1000 Words (HRC-E.B.)

38 psi . well that would be my guess



Getting the most drive requires smoothness and the ability to feel what is going on with the rear tire. With no information to go from nobody here will have any information worth a shit to help you.

My only advise is to find out exactly what your suspension settings were and what the actual hard numbers were (ride height, swing arm angle, front and rear preload)

If I had that information I could offer you some info as far as maximizing rear grip and feedback
 
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Discussion Starter · #3 ·
Re: You Know You Are Not Making It When... Image Worth 1000 Words (sp2pilot)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sp2pilot »</TD></TR><TR><TD CLASS="quote">38 psi . well that would be my guess

</TD></TR></TABLE>

+1 I would start by dropping tire pressure 7-8 lbs....glad you're OK!
 
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Discussion Starter · #4 ·
As sp2 mentioned your pressure seems a little on the high side for track use.
For Pilot Powers it is recommended you run 28 front and 30 psi rear.
 
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Discussion Starter · #6 ·
Can't remember whether it was on this forum or another, but I seem to remember that a Michelin rep had indicated that the pressures to be used at the track for Pilot Power were more in the vicinity of 34-36 Front and 36-38 Rear, as opposed to 29-30 front and rear for most other street tires?

As regards rear-end settings, I had not experienced any issues getting traction and drive exiting the corner. I was surprised to see the back end come around on me in the middle of the turn on neutral throttle...

Even assuming it would have given me feedback, what the hell could I have done to prevent it from coming around at that point?
 
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Discussion Starter · #7 ·
Re: (HRC-E.B.)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HRC-E.B. »</TD></TR><TR><TD CLASS="quote">Can't remember whether it was on this forum or another, but I seem to remember that a Michelin rep had indicated that the pressures to be used at the track for Pilot Power were more in the vicinity of 34-36 Front and 36-38 Rear, as opposed to 29-30 front and rear for most other street tires?

As regards rear-end settings, I had not experienced any issues getting traction and drive exiting the corner. I was surprised to see the back end come around on me in the middle of the turn on neutral throttle...

Even assuming it would have given me feedback, what the hell could I have done to prevent it from coming around at that point?</TD></TR></TABLE>


Ok if you want help then you better be able to take a little blame, (or all of it actually)

Your information is dead wrong about starting pressures.

Feedback is that little thing that lets you know you are about to lose the rear and adjust accordingly. (I spin the rear harder off corners them most ask the people that ride with me or just watch one of my videos)

If you have feedback and feel the rear begin to spin up, (there are little indicators just before it breaks lose) you add peg pressure, lower your shoulders, counter steer, move your weight back, ....you do alot of stuff you don't just hit the ground unless you just don't know what the hell you are doing,(in that case you will hit the ground alot,get used to it)

My point is you obviously did not have enough grip at the exact moment (about 1/2 second before the shutter closed on that shot) that you expected.

You decide, you want to learn from this or just write it off as an unknown and never have the confidence to come back from it. Crashing sucks. It is just one of the harder components of learning where your personal limits are.
 
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Discussion Starter · #9 ·
Re: (HRC-E.B.)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HRC-E.B. »</TD></TR><TR><TD CLASS="quote"> a Michelin rep had indicated that the pressures to be used at the track for Pilot Power were more in the vicinity of 34-36 Front and 36-38 Rear, as opposed to 29-30 front and rear for most other street tires?</TD></TR></TABLE>

the first mistake was listening to the tire "rep". he obviously doesn't have a clue as to track psi's.

Micheline runs in the 29-30 front and rear ranges, IF NOT LOWER. I've seen some guys running 26 front and 28 rear (and lower) in the race compound tires.

the specs the tire rep gave you was for street riding......


not the track....


if you set at 38 rear cold, you were somewhere in the vicinity of 42-44 hot, when the tire was warmed up, if not higher.

nice ****** leading up to your rear tire though.....
glad you're ok........
 
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Discussion Starter · #10 ·
Re: (Rigor)

I just came back from a track day in Omaha. And the Michilen rep told me to run 29 ft and 26 rear. The traction was great and the wear was minimal. Prior to that I was running 30 30. Go figure.
 
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Discussion Starter · #11 ·
Re: (ur-n-8)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ur-n-8 »</TD></TR><TR><TD CLASS="quote">I just came back from a track day in Omaha. And the Michilen rep told me to run 29 ft and 26 rear. The traction was great and the wear was minimal. Prior to that I was running 30 30. Go figure.</TD></TR></TABLE>

Was that with Pilot Power tires or other Michelins? Once again, I could be wrong, but the numbers I heard from different sources with regard to these particular tires were consistently WAY higher than what is the norm for other tires. Has to do with the fact that their carcass is different to deal with the softer synthetic compound. I'd be curious to know what the REAL recommendation is in order to use what is best for these tires.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sp2pilot »</TD></TR><TR><TD CLASS="quote">


Ok if you want help then you better be able to take a little blame, (or all of it actually)

Your information is dead wrong about starting pressures.

Feedback is that little thing that lets you know you are about to lose the rear and adjust accordingly. (I spin the rear harder off corners them most ask the people that ride with me or just watch one of my videos)

If you have feedback and feel the rear begin to spin up, (there are little indicators just before it breaks lose) you add peg pressure, lower your shoulders, counter steer, move your weight back, ....you do alot of stuff you don't just hit the ground unless you just don't know what the hell you are doing,(in that case you will hit the ground alot,get used to it)

My point is you obviously did not have enough grip at the exact moment (about 1/2 second before the shutter closed on that shot) that you expected.

You decide, you want to learn from this or just write it off as an unknown and never have the confidence to come back from it. Crashing sucks. It is just one of the harder components of learning where your personal limits are. </TD></TR></TABLE>

I am definitely prepared to take the blame. As I mentioned, I would like nothing more than (a) knowing what to do in case this happens again (as mentioned, I wasn't prepared for this, so I would have been hard pressed to see it coming. Now is a different story) and (b) knowing what pressures I should be running in my damn tires (though I know for a fact that a lot of people simply repeat information they've heard without being familiar with the particular equipment being used, on the assumption that "all tires are the same", which is false).

SP2: as indicated earlier, this crash did not happen at the exit of the corner, where I do spin the rear occasionally also. It happened more toward <U>the apex/middle of the turn, on neutral throttle</U>. Other than hanging off more to keep the bike more upright, is there anything I could do that would maximize grip at that stage in a turn? You seem to be suggesting that loading the outside peg will increase grip (which, from a physics standpoint appears to make sense).

I would be ultra stupid if I were not prepared to learn from this. There is nothing good about a crash if you can't learn from it. Keep it coming.
 
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Discussion Starter · #12 ·
Re: (HRC-E.B.)

How scrubbed are those tires? It may be my imagination but I think I can see the blue lines still on them. Did you walk back and look at where it all went bad (tracks up here don't see use all year so they get very dirty, and bumpy from frost)?
 
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Discussion Starter · #13 ·
Re: You Know You Are Not Making It When... Image Worth 1000 Words (HRC-E.B.)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HRC-E.B. »</TD></TR><TR><TD CLASS="quote">

</TD></TR></TABLE>

I could have saved that . . . .

 
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Discussion Starter · #14 ·
Re: You Know You Are Not Making It When... Image Worth 1000 Words (spezjag)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by spezjag »</TD></TR><TR><TD CLASS="quote">

I could have saved that . . . .

</TD></TR></TABLE>
 
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Discussion Starter · #15 ·
I had a similar kind of crash. Tight line in a slow turn and the back just WENT. In my case I probably got into some bad pavement and perhaps some dust too. Too tight of a line. I was on Pirelli slicks-30/30 psi-lap 4. With Power street tires I was running around 30/30 but the back would get loose on the track and I was advised by multiple people to run higher pressures with these tires to reduce carcass flex and overheating. Very different from Power Race tires which run "normal" race tire pressures in the front and pretty low(22psi) in the back. Yep we make mistakes but I think every now and then the hand of god reaches down and smacks us down for a little entertainment..........my crash was the first one since I started doing track days back in 1999.
 
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Discussion Starter · #16 ·
Re: (Velociraptor)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Velociraptor »</TD></TR><TR><TD CLASS="quote">I had a similar kind of crash. Tight line in a slow turn and the back just WENT. In my case I probably got into some bad pavement and perhaps some dust too. Too tight of a line. I was on Pirelli slicks-30/30 psi-lap 4. With Power street tires I was running around 30/30 but the back would get loose on the track and I was advised by multiple people to run higher pressures with these tires to reduce carcass flex and overheating. Very different from Power Race tires which run "normal" race tire pressures in the front and pretty low(22psi) in the back. Yep we make mistakes but I think every now and then the hand of god reaches down and smacks us down for a little entertainment..........my crash was the first one since I started doing track days back in 1999.</TD></TR></TABLE>

Exactly WHERE can we get reliable information as to which pressure is required for each particular tires??? You seem to have fairly specific info for Power Race tires, but where did you get that? Anybody you can direct me to? Your info regarding carcass flex echoes what I had heard, but I don't know where to look for the real info.

Thanks!
 
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Discussion Starter · #17 ·
Re: (HRC-E.B.)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HRC-E.B. »</TD></TR><TR><TD CLASS="quote">Was that with Pilot Power tires or other Michelins? Once again, I could be wrong, but the numbers I heard from different sources with regard to these particular tires were consistently WAY higher than what is the norm for other tires. Has to do with the fact that their carcass is different to deal with the softer synthetic compound. I'd be curious to know what the REAL recommendation is in order to use what is best for these tires.


</TD></TR></TABLE>

Mich recommends much LOWER pressures then other manufacturers on the new Pilot powers race tires

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HRC-E.B. »</TD></TR><TR><TD CLASS="quote">

knowing what pressures I should be running in my damn tires (though I know for a fact that a lot of people simply repeat information they've heard without being familiar with the particular equipment being used, on the assumption that "all tires are the same", which is false). .</TD></TR></TABLE>

it seems you made a very serious assumption without confirmation about one of the most important aspects of track prep


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HRC-E.B. »</TD></TR><TR><TD CLASS="quote">


SP2: as indicated earlier, this crash did not happen at the exit of the corner, where I do spin the rear occasionally also. It happened more toward <U>the apex/middle of the turn, on neutral throttle</U>. Other than hanging off more to keep the bike more upright, is there anything I could do that would maximize grip at that stage in a turn? You seem to be suggesting that loading the outside peg will increase grip (which, from a physics standpoint appears to make sense).

I would be ultra stupid if I were not prepared to learn from this. There is nothing good about a crash if you can't learn from it. Keep it coming.</TD></TR></TABLE>

Without being there and seeing it all I have is your feedback on the crash.

correct me if I am wrong but you describe the following;

in a corner a little too tight as you approach apex on neutral throttle the rear steps out big time.

My take on what possible could have contributed to this.

Riding too stiff with too much grip pressure and can over isolate a rider to the small indicators that the bike is beginning to lose grip. Also by riding looser the bike has the ability to react less violently to track imperfections and inconsistent traction issues.

Some riders trail brake towards apex without realizing the bike tends to rotate from the weight transfer off the rear contact patch, (advanced riders use this rotation to get the bike turned as well as shortening the turn in transition points)

Too much rebound in the rear shock will cause loss or rear grip on turn in while trail braking

too little preload on rear shock will cause the bike to squat and possibly bottom causing loss of grip.


In long extended sweeping turns that the bike is healed over for extended periods 2 to 3 seconds at full lean can overwhelm the contact patch by a phenomenon know as pyro spikes. it is basically the rear tire heats to the point it goes greasy in the turn.


The fact is unless you are Valentino Rossi you probably were not the fastest guy in that turn on that exact line that day. So it comes back to rider technique and bike set up.

What shock/fork are on the bike (my guess they are stock)

What was the sag setting you put into the bike that day?

have you adjusted ride height?

what size tires are on the bike?
 
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Discussion Starter · #18 ·
Alex over at the Rogue site is a Michelin rep. He seems to know his stuff really well. Also the local Michelin guy at Pacific Raceways told me the same thing as I heard from Alex. I tend to trust the people who sell the tires and are out there on the weekends supplying tires to racers(I am not a racer myself-too old and slow). One would think that a rep supplying tires at a race track would want to give the best info possible so people will like the tires and buy more.
 
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