Okay Barry let me ask you some questions if you don't mind. I'm not interested in calling you names or any of that.
So i assume you have watched the Video posted above, and have concluded that the method shown here is a kind of 'watered down' version of backing it in. That seems feasible to me, like you said he'd doing it at a relatively low speed, not actually continuing into a corner and even mentions that the method can be used for looking cool.
Clearly the common perception is that the method in this video is fundamentally the same as it would be on a track in a high speed scenario, but you claim this is absolutely not the case, so would you please outline just one more time the method for backing it in that you feel is correct in a racing situation.
If posible please try to avoid describing emotions (like terror) and vague statements like 'very sensitive balance of physical conditions'. Smiley faces don't make your argument any clearer to digest either. So how about a bullit point list of actions from the rider needed to back it in your way, from being wide open on the straight to meeting the apex of the corner with the bike in line again. Where relevant mention not only opperation of brakes, clutch gears etc, but which controls are left untouched, and the general movement of the bike i.e. which wheels are turning, which wheels are pointing where and if any of them are off the ground. If you can write this list relative the the instructions in this video so it is clear how you feel they differ.
Cheers
Posted it all before ....... search is your friend.
But a few points:
1. I know of nobody who tries to back it in ......... not saying it isn't done what I'm saying is that when observed it is more of a consequence than a conscious attempt to hang the back out. Except in very rare cases on tarmac ( dirt yeah it happens a bit, especially say to try and duck inside someone ) )
2. Neeves? Jeeeves? what ever is partially right ....... it occurs because of a breaking traction between the rear tyre and the surface it is traveling on, and a moment around the front tyre contact point which mainly occures and when the bikes ability to provide the centripetal force to exactly counter the centrifugal force due to actually taking the corner .........( he almost gets to that part too right at the end, but fails .... possibly cos he isn't actually taking a corner. In effect the guy had no centrifugal force happening at all ) Also he was not moving very fast at all, and I think he should have picked a better bike. Though it probably was one of the only ones he could easily get hold of without a slipper ..... so maybe it was the easiest thing at the time
When taking the corner and attempting to track around it the centripetal force is opposing the centrifugal force via the two contact patches, front and rear tyre.
On each tyre we can say that the centripetal force is maintained by the force needed to shear the mating surface of the contact patch as a joint in shear whereby for a given material the contact patch will approach shearing in proportion to changes in the forces on it. Such forces as the centrifugal force of the corner or other vectored forces such as occur via change in the tyres angular velocity.
But we also need to remember that that force needed to shear traction changes due to the actual frictional force on it ie. Friction formula F=uN ( Used u for mu ( coefficient of friction) ) eg gravity and the mass of the bike /rider.
Now when coming to a corner and braking hard with the front brake the force N on each tyre changes:
the downward force on the front increases so the traction between rubber and surface rises ........... in effect the front gets planted more
the force making traction at the rear however goes very light ...... in fact as is often seen its no longer in contact ....... ie the force is zero or very minimal
now you have to think back to that actual centrifugal force and the fact that it was being opposed by both the front and back tyre traction, now suddenly there is noting to oppose it at the rear tyre ( or very little ) when its even still on the ground. So with nothing to oppose the centrifugal force it now becomes a force that creates a moment around the front tyres ( in some instances felt by the rider in the bars ) and forces the rear out ....... if kept in check the rider is aided by the fact that the more he lets it hang out the more the increasing sideways force as the tire is now scraping at a vector sideways ......( usually a very small force unless it finds traction then it instantly becomes a huge impulse and results in a highside )
Now some other important factors. ( bits that were missing also from Mr Neeves vid. )
The faster you take a corner ( change direction ) the closer you get to the point were the tyres cannot provide enough centripetal force to counter the centrifugal force. Thats a cornering limit. So when getting near the limit regardless of applying any brake front or rear, even if you were tracking true there is a centrifugal force at which the tyres will let go.
Now you have to think in 2d vectors ....... at speed, as in a race, you are always close to the point were centripetal force = centrifugal force.
Now in terms of observed cases of the rear stepping out ( commonly called Backing it in ), at genuine racing speed were you are already on the limit, we need only to cause to rear end to have the slightest change to cause the rear end traction to decrease to the amount whereby the centrifugal force of the corner begins to push the rear outward.
At this point with the front doing all, or just about all, the stopping hence the rear traction being absent ( tyre in the air ) or just touching, many things can break that tiny amount of remaining traction when present:
Backing off
cracking the throttle ( especially on dirt )
weight shift
weight bounce
throwing a stick in the back spokes
applying the back brakes
downshifting
the latter three of these have about the same effect as when the rear wheel is so light the wheel will change its spin so rapidly and even lock with the rear brake, the first example are way subtler and do have use at high speeds.
Now what is the difference between backing it in and skidding .....
When emergency stopping one downshifts and brakes hard ..... if this is the case why is it not backing in a bike? and isn't intending to maintain speed at all ...... Something is missing.
When a bike is backing it in it is experiencing a centrifugal force due to turning into a corner, this will cause the rear to step out for many an input as pointed out before. Because of the existence of the centrifugal force of coming into the corner, as well as the almost non existent rear traction due to some front end braking. The input needed to begin the rear wandering outward becomes less for higher speeds.
This is when we see rider body placement, bike placement and throttle control being contributing factors and indeed one would never touch the rear brake or downshift in such situations. Therefore if they are not always present such as the front brake and centrifugal force due to cornering. Oddly if the rear is still on the ground it is possible to get it to sit down even more by trailing the rear brake which creates a moment around the rear wheel and translates to a force with a resultant downward force at the swingarm pivot hence which then act as a moment around the front axle tending to force the rear back down ...... in any case that usually after the front has wandered and the need arose to ... the rear .......
As in my original since braking and downshifting are not always present in getting the back end out on a bike .... they are therefore not what initiates backing in. Indeed in some situations you would not do either for fear of death.
PS. This is not the common perception for high speed
where do you get that crap from ..... even Neeves gives that disclaimer .... you need to watch again. And if its the "common perception" on here that you talk of , the you have to remember many of these folk have never even ridden a bike ..... so where do they get their perceptions from?
which was one of my original points given that the opinions being thrown around were so far off the mark , and indeed considered downright dangerous by some of us more "uncommon perceivers", eg did you bother to read someof the comments on that vid. seems to be a few of us "uncommon types" out there.
thats cos I think you need to get over your distraction with emoticons .....
SHould I wish to be so churlish ...... I would be sooking about half the avatars on here
including mine actually
