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October 18th, 2020, 02:45 PM   #41
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Quote:
Originally Posted by Segfault View Post
Your opinion is based on "butt feeling", mine is not opinion, it is based on science.

You are right there is low pressure area behind an object which moves thru air and it "pulls back". What you ignore is the fact there is also high pressure area in front of that object. When the bike from behind B approaches the bike in front A the high pressure area from B starts neutralizing the pullback power bike A is experiencing. This high pressure area in front is much smaller than the low pressure area in back, but it is there.
There is absolutely no scientific explanation how the bike behind could slow down the bike ahead, unless the rider in the back is Magneto ...
Again NASCAR makes these effects more obvious. When 2 or more cars draft up to a lone lead car, you will notice how the chasing pack deliberately remain constant to one another keeping the gap the same at all times. This allows the benefit to the lead car to actually run a higher top speed. If the second car disrupts the constant by letting the gap increase/decrease or pulling out of the draft the benefit is lost.

Cars and bikes though, not really the same and I've not witnessed it much other than perhaps 125/moto3.

What I have seen quite often is a line of bikes running onto a straight, not at all nose to tail sometimes quite a distance apart, and we all marvel including the commentators how bike/rider number 4 somehow ends up in the lead, while the poor old leader ends up in 4th.

I would postulate we have bikes running down a straight, they are all geared correctly to be hitting close to the rev limiter in 6th gear and hence they don't really have the capacity to endlessly go faster, the bike in 4th cant be running 20mph quicker without blowing the engine. How does 4th end up 1st? It could simply be down to increasingly improved acceleration for each bike in line in the tow. Yet when we see this happen it certainly appears the lead bike in a group of drafting bikes tends to suffer rather benefiting in any way, no positive air pressure pushing going on that I can see, that would surely help the leader as the bike behind approaches.
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October 18th, 2020, 03:21 PM   #42
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Originally Posted by Keshav View Post
Not based on "butt feeling". It's accepted science based wisdom passed on by professionals, never in more than 35 years have I heard any rider dispute this. But of course "a guy on the internet" wants to argue otherwise. Believe what you will. It's not my job to change your mind. I find in situations like this, I could have Stephen Hawkins come and explain why a person is wrong, but it's a matter of pride and most guys on internet forum take stuff too personally and are not open to any differing opinion.

Leave us not drag this out. I don't want to get into a long debate. Nobody is going to change their mind. Positions are stated. People get bored with this kind of thing. Let it be. OK?
I take you at your word because you have raced as I said before the further discussion, and the physics of all this is complicated, and seems to differ between sports, cars vs motorbikes vs bicycles, aero changes things as it did in F1 where slipstreaming became a thing of the past etc.

The only thing is while the fact that you have raced is fairly clinching in any discussion such as this in all my years of following MotoGP I have never heard anyone, commentator or rider, complain about towing ruining a qualifying lap or slowing down the tower, as in this case where Dovi’s complaint seems to have been exclusively that the tow allowed Petrucci to set a time faster than he could have achieved with his own intrinsic pace, and he straight out said he wasn’t looking for any help such as a tow from Petrucci.

Last edited by michaelm; October 18th, 2020 at 04:43 PM.
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October 18th, 2020, 04:09 PM   #43
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Quote:
Originally Posted by birdman View Post
Again NASCAR makes these effects more obvious. When 2 or more cars draft up to a lone lead car, you will notice how the chasing pack deliberately remain constant to one another keeping the gap the same at all times. This allows the benefit to the lead car to actually run a higher top speed. If the second car disrupts the constant by letting the gap increase/decrease or pulling out of the draft the benefit is lost.

Cars and bikes though, not really the same and I've not witnessed it much other than perhaps 125/moto3.

What I have seen quite often is a line of bikes running onto a straight, not at all nose to tail sometimes quite a distance apart, and we all marvel including the commentators how bike/rider number 4 somehow ends up in the lead, while the poor old leader ends up in 4th.

I would postulate we have bikes running down a straight, they are all geared correctly to be hitting close to the rev limiter in 6th gear and hence they don't really have the capacity to endlessly go faster, the bike in 4th cant be running 20mph quicker without blowing the engine. How does 4th end up 1st? It could simply be down to increasingly improved acceleration for each bike in line in the tow. Yet when we see this happen it certainly appears the lead bike in a group of drafting bikes tends to suffer rather benefiting in any way, no positive air pressure pushing going on that I can see, that would surely help the leader as the bike behind approaches.
We used to call it the slingshot effect. Talk to anyone who's ever been passed coming off the wall at Daytona by a slower rider and tell them it's not a real thing. (I don't mean you should mate)
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October 18th, 2020, 04:48 PM   #44
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Quote:
Originally Posted by Keshav View Post
Not based on "butt feeling". It's accepted science based wisdom passed on by professionals, never in more than 35 years have I heard any rider dispute this. But of course "a guy on the internet" wants to argue otherwise. Believe what you will. It's not my job to change your mind. I find in situations like this, I could have Stephen Hawkins come and explain why a person is wrong, but it's a matter of pride and most guys on internet forum take stuff too personally and are not open to any differing opinion.

Leave us not drag this out. I don't want to get into a long debate. Nobody is going to change their mind. Positions are stated. People get bored with this kind of thing. Let it be. OK?
Butt feeling is probably correct though, given your butt has frequently been on the seat of a racing motorcycle.
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October 19th, 2020, 10:08 AM   #45
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Originally Posted by p4p1 View Post
2 excellent weekends for Alex Marquez in a row. Strongly starting to think that HRC made the wrong call replacing him with Pol.
100% agree they should have waited. Pol is highly over rated. come to think of it so is 20, and 4. crowning 20 the champ because he won a race claiming he is like marquez was just not fair to marquez and being blind. 20 was never had a fight with 46 so he was allowed to be praised by the media. 93 destroyed 46 so he was a villian.

remember it took 20 a year to win a race and the media was all over him saying he is the next coming. 93 won back to back championships and at the time was never mentioned.
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October 19th, 2020, 11:28 AM   #46
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Quote:
Originally Posted by mark419ny View Post
100% agree they should have waited. Pol is highly over rated. come to think of it so is 20, and 4. crowning 20 the champ because he won a race claiming he is like marquez was just not fair to marquez and being blind. 20 was never had a fight with 46 so he was allowed to be praised by the media. 93 destroyed 46 so he was a villian.

remember it took 20 a year to win a race and the media was all over him saying he is the next coming. 93 won back to back championships and at the time was never mentioned.


For sure Fabio is very inconsistent. I think we may see a repeat of his moto3 years.
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October 19th, 2020, 01:10 PM   #47
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The elephant in the room; all riders have favorite tracks where they gel with the circuit, as, well as bogey tracks. The loss of Thailand, China, USA, Australia etc. really does skew the results. The fact that some riders get to race multiple times at tracks that favor their bike and/or their riding style throws outsized advantage to certain riders
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October 19th, 2020, 02:20 PM   #48
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This maybe true, but it is also just the fact that there are fewer tracks. If yer gonna race, ya gotta do it at a track. Just like always, the better you are, the faster you’ll go. Doesn’t matter where. Get better at your bogey tracks is the correct advice to hand out. (Not that I’m dispensing any, he he.)
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October 20th, 2020, 01:19 AM   #49
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I always thought it was more that the bikes didn't gel with a circuit, rather than the rider.
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October 20th, 2020, 06:55 AM   #50
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Originally Posted by SlartyBartFast View Post
I always thought it was more that the bikes didn't gel with a circuit, rather than the rider.
It's both, but recall if you will, Stoner was largely unbeatable at Phillip Island regardless of which bike he was on. He won at Qatar in the old 250 class and came back to win there in 2007, 2008, 2009, 2011. (2006 - his rookie year - he was 5th on a half-ass LCR Honda with shitty mismatched tires)

Riders at all levels agree that they're more comfortable or more adept, on one side vs the other. If you keep track of places where a given rider makes his passes they tend to be mostly in a left or right. Of course they have to be good at both, but there's always a preference, so tracks with predominantly left turns will favor certain riders and right turns, others. Stoner, as well as many of the great American riders, started out in pee wee flat track classes and on into their teen years, on tracks where they only turned to the left, so for sure left turn passes were deeply in the their DNA.
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Last edited by Keshav; October 20th, 2020 at 12:15 PM.
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