A Fix For Classic Car Show Power Voting
by: Ray Taylor
As I wrote in a previous article, "Classic Car Show Power Voting", there has been a real challenge at my San Diego Classic Car & Cycle Show & Swap with Power Voting. I think I may have found a way to help reduce the imbalance in voting results at People's Choice type of Car Shows.
For those who don't know, Power Voting is when groups such as Car Clubs go to a People's Choice Type Car Show and vote for all their club members and no one else. I believe people should be able to vote for whomever they please. The challenge comes about when those attending the event don't participate by casting their votes for their favorite vehicles. Without a large number of votes being cast, Power Voting can sway the results so the majority of the trophies go to the Power Voting Group.
Voter Apathy strikes again! I think I have found a fix that will help make the voting results more equitable for all entries.
I am going to start doing at my Car Shows what the state of New Mexico is doing to help encourage their people to get out and vote. They bribe them! How? When they vote, they are entered into a Voter's Lottery! That's exactly what I am going to do too!!! When you cast your vote at my events from now, on you will receive a ticket for a Special Raffle just for Voters! Bribery works well with politicians; I think it will help cancel out the effects of Power Voting.
If you have any questions or suggestions about this new addition to my shows, please feel free to contact me. I really appreciate and enjoy hearing your ideas and feedback.
On Memorial Day, Monday, May 28 from 6am to 2pm we will be holding our Annual "Salute Our Troops" Classic Car & Cycle Show & Swap in the SW lot of San Diego Qualcomm Stadium. All Active Military will be given Free entry. If they are in Uniform, I will also treat them to Free Refreshments.
Please come out on Memorial Day, Monday, May 28 and show your support!
Grab A Friend, Bring a G.I., and We'll See Ya There!
Ray Taylor
www.CarsNet.com
Sunday, April 29, 2007
Thursday, April 19, 2007
MOTORCYCLE TIRE BASICS
MOTORCYCLE BALANCING ACT
as they relate to single track vehicles (motorcycles in other words).
it falls over, if left to its own devices when stationary.
is to move the tyre contact patch line to under the new position of the C.of
G. If the bike is stationary this can only be done to a limited extent by moving
the bars, however once under way we can steer the bike to place the position
of the tyre line wherever we need it, and this is why it is easier to balance
when moving. The other way to maintain low speed balance is by moving the combined
C.of G. of both the rider and machine to above the line joining the tyre contact
patches. This is what trials riders are doing when moving their bodies from
side to side whilst standing up. The high C.of G. of the rider has more effect
on the toppling over moment and also gives more control over the position of
the bike's C.of G. Thus to a great extent the process of low speed balance is
dependent on the individual skill of the rider. In addition, some bike parameters
can also affect the ease of remaining upright, the main ones being:
# 1. A low C.of G height helps.
# 2. A large trail changes the position of the tyre line more for a given handlebar
movement.
# 3. A small rake angle reduces the fall of the steering head when the bars
are turned away from the straight ahead position, assisting with the balance
process.
to maintain its plane of rotation. In other words, while it can easily be moved
laterally along the axis of spin, it resists tilting about any other axis, and
more importantly, when it is tilted it automatically causes a strong twisting
moment about an axis at 90 degrees to that of the original tilt. This twisting
effect increases as the speed of the wheel rises, this is known as gyroscopic
precession. When you have finished reading this, I expect you to go and remove
the front wheel from your brother's mountain-bike, if you then obey the following
intructions you will get a graphic practical demonstration of the strength of
these precessional forces, which are so vital to the balance and steering of
any bike. Firstly hold the wheel upright, as in, get your young brother (well
he won't be out riding, will he?) to spin it so that the top of the wheel is
moving away from you, as if it were the front wheel of a machine you were riding.
If you then try to tilt the spindle to the LEFT (equivalent to banking your
machine) you will find that the wheel _turns instantly and strongly to the LEFT,
as if steered by an invisible hand. In other words, your attempt to tilt the
wheel about its fore-and-aft axis has produced a torque swivelling it about
its vertical axis. Now start again but this time turn the wheel to the LEFT
about a vertical axis, just as sharply and strongly it will bank to the RIGHT.
Try both these manoeuvres again, but do it at different wheel speeds and tilting
speeds, you will see that the precessional forces depend strongly on these factors.
Note particularly, the directions in which these forces operate as this is important
for the automatic retention of balance. Let us now see how these forces keep
the machine balanced and on a relatively straight path without assistance from
the rider. Suppose the bike, whilst travelling along at a normal speed, starts
to fall to the left under the action of some extraneous influence. As we have
just seen, gyroscopic precession of the front wheel immediately turns it to
the left. This sets the machine on a curved path (to the left), so creating
a centrifugal force (to the right), which counters the lean and tends to restore
the machine to the vertical, the precessional forces are thus reversed tending
to restore the steering to the straight ahead position. In practice, that which
we regard as riding in a straight line, is really a series of balance correcting
wobbles, if we could look at the actual paths taken by the centre-lines of the
wheels, we should see that the front wheel path continually crosses that of
the rear. In the explanation above, I have only described the effects on the
front wheel, precessional forces are at work on the rear also, but it is much
harder to steer the rear wheel independently, as the whole bike must yaw, rather
than just the wheel and forks, as on the front. Hence, only a small contribution
is made to the auto-balance mechanism by the rear. We have now considered balance
in a straight line, but as we lean when cornering, there must be other factors
at work to maintain equilibrium under these conditions.
opposing moments, the one due to centrifugal force acting outward, and the other
to gravitational force acting downward (both acting through the C.of G.). The
actual angle, which depends on the radius of the turn and the speed of the machine,
is that at which the resultant of the two forces passes through a line joining
the front and rear tyre contact patches. This is the steady-state roll axis.
But how do we actually initiate the turn - do we lean or do we steer first?
Let's see what happens with each method. If we turn the handle-bar in the direction
in which we want to go, both centrifugal force and the front wheel precession
would cause the bike to topple outward, and that leads to gravel rash. But if
we momentarily try to turn the bar quickly in the opposite direction, (sometimes
known as counter steering) then these two forces will combine to bank the machine
to the correct side. Gravity will then augment the banking effect and this,
in turn, will give rise to gyroscopic forces helping to steer the front wheel
into the curve, whereupon the processes for maintaining balance as described
above take over and keep the bike on our chosen path. This is all very well,
I hear you say, but if this is the way to corner, how come we can steer a bike
no-hands. Well, it certainly is possible to do so, but only with a lot more
difficulty. Precise control and tight turns are difficult to accomplish without
handle-bar manipulation. Just try it! Let's consider the no-hands situation.
As we saw earlier, simply banking the bike steers the front wheel in the correct
direction automatically, through precession. But how do we make the bike lean
in the first place, what do we have to push against? There is nothing solid
to push against and so the only way to apply bank (without the facility of steering),
is to push against the machine with the inertia of our own body. This means
in practice, that in order to lean the bike to the right, we must initially
move our body to the left. So now we have two possible methods of initiating
a turn, and it is interesting to note that in both of them (banking and reverse
handle-bar torque) our physical effort is in the opposite sense to that which
might be thought natural, but when learning we adapt quickly and the required
action becomes subconsciously automatic. It is these reverse actions that require
us to learn to ride in the first place, when learning most of us wobble about
out of control until our brain latches on to the fact that counter-steering
and counter-leaning is the way to do it. Once the brain has switched into reverse
gear, it becomes instinctive and is usually with us for life, and we could return
to riding after a long layoff with no need to relearn the art of balancing or
steering. So which of these two possible methods of initiating a turn do we
use in practice? We probably subconsciously combine both methods, and the pressure
on the inner handgrip is partly forward (counter-steering) and partly downward
(banking). Remember though, that the actual counter-steering movement is very
small, since gyroscopic precession depends for its strength on the speed of
movement not on the amount of movement. If you still don't believe that steering
to the opposite side works, then next time you are out riding, try jerking the
bars quickly to one side, and see what happens. Leave yourself plenty of road
if your reactions are a bit on the slow side. Do this at about 40 mph., and
don't blame me if you fall off. The relative proportions with which we combine
the two methods depend partly on riding style but also on speed and machine
characteristics. For example, a heavy machine with light wheels at low speeds
demands a different technique from that applicable to a light weight machine
with heavy wheels at high speeds, and hence the two machines will have a different
feel. But humans adapt quickly and the correct technique soon becomes second
nature. It may seem strange that in the above discussion no mention has been
made of such important parameters as, steering geometry, wheel and tyre size,
wheelbase, frame stiffness and so on. This is simply because, balance and the
ability to start and maintain a turn can be achieved within a wide range of
these parameters. That is not to say that these factors are unimportant. We
shall now look a little more closely at one of the more important parameters
that come under the heading of steering geometry, i.e. TRAIL. Consider first,
which shows the basics of steering geometry.
of straight line stability, in addition to that obtained by precessional effects
as described above. But trail also introduces other effects which are vital
to the feel and handling of the motorcycle.
is much greater than that of the front, the rear wheel is the more important
in this respect. The reverse is actually the case for several reasons.
© Tony Foale 1986 -- 1997
Let's return to basics and look at the mechanisms of stability and steering,as they relate to single track vehicles (motorcycles in other words).
BALANCE.
As a single track vehicle, a motorcycle lacks inherent static balance, i.e.it falls over, if left to its own devices when stationary.
Once moving above a certain speed however even the most uncoordinated riders
find that the machine seems to support itself. So it is obvious that there are
two aspects of the balance process, the low speed case and that in the higher
speed ranges. There have always been clever sods who can balance indefinitely
on a stationary bike, but for most of us we need a minimum of forward motion
before this is possible. However, at these low speeds it is necessary to move
the handlebars from side to side to stay upright, and as all trials riders know,
it is easier if we stand on the footrests instead of sitting down. Let's examine
why. Now, if the combined centre of gravity (C.of G.) is vertically above the
line joining the front and rear tyre contact patches, then balance is achieved,
but this is an unstable situation, any small distubance such as a light breeze
will be enough to start a topple over, i.e. the C.of G. moves sideways.
is to move the tyre contact patch line to under the new position of the C.of
G. If the bike is stationary this can only be done to a limited extent by moving
the bars, however once under way we can steer the bike to place the position
of the tyre line wherever we need it, and this is why it is easier to balance
when moving. The other way to maintain low speed balance is by moving the combined
C.of G. of both the rider and machine to above the line joining the tyre contact
patches. This is what trials riders are doing when moving their bodies from
side to side whilst standing up. The high C.of G. of the rider has more effect
on the toppling over moment and also gives more control over the position of
the bike's C.of G. Thus to a great extent the process of low speed balance is
dependent on the individual skill of the rider. In addition, some bike parameters
can also affect the ease of remaining upright, the main ones being:
# 1. A low C.of G height helps.
# 2. A large trail changes the position of the tyre line more for a given handlebar
movement.
# 3. A small rake angle reduces the fall of the steering head when the bars
are turned away from the straight ahead position, assisting with the balance
process.
The balance mechanism at higher speeds is more complex, but at least is largely
automatic and independent of rider ability. To understand the action it is necessary
to look at a few properties of gyroscopes, which is another way of describing
spinning motorcycle wheels.
to maintain its plane of rotation. In other words, while it can easily be moved
laterally along the axis of spin, it resists tilting about any other axis, and
more importantly, when it is tilted it automatically causes a strong twisting
moment about an axis at 90 degrees to that of the original tilt. This twisting
effect increases as the speed of the wheel rises, this is known as gyroscopic
precession. When you have finished reading this, I expect you to go and remove
the front wheel from your brother's mountain-bike, if you then obey the following
intructions you will get a graphic practical demonstration of the strength of
these precessional forces, which are so vital to the balance and steering of
any bike. Firstly hold the wheel upright, as in, get your young brother (well
he won't be out riding, will he?) to spin it so that the top of the wheel is
moving away from you, as if it were the front wheel of a machine you were riding.
If you then try to tilt the spindle to the LEFT (equivalent to banking your
machine) you will find that the wheel _turns instantly and strongly to the LEFT,
as if steered by an invisible hand. In other words, your attempt to tilt the
wheel about its fore-and-aft axis has produced a torque swivelling it about
its vertical axis. Now start again but this time turn the wheel to the LEFT
about a vertical axis, just as sharply and strongly it will bank to the RIGHT.
Try both these manoeuvres again, but do it at different wheel speeds and tilting
speeds, you will see that the precessional forces depend strongly on these factors.
Note particularly, the directions in which these forces operate as this is important
for the automatic retention of balance. Let us now see how these forces keep
the machine balanced and on a relatively straight path without assistance from
the rider. Suppose the bike, whilst travelling along at a normal speed, starts
to fall to the left under the action of some extraneous influence. As we have
just seen, gyroscopic precession of the front wheel immediately turns it to
the left. This sets the machine on a curved path (to the left), so creating
a centrifugal force (to the right), which counters the lean and tends to restore
the machine to the vertical, the precessional forces are thus reversed tending
to restore the steering to the straight ahead position. In practice, that which
we regard as riding in a straight line, is really a series of balance correcting
wobbles, if we could look at the actual paths taken by the centre-lines of the
wheels, we should see that the front wheel path continually crosses that of
the rear. In the explanation above, I have only described the effects on the
front wheel, precessional forces are at work on the rear also, but it is much
harder to steer the rear wheel independently, as the whole bike must yaw, rather
than just the wheel and forks, as on the front. Hence, only a small contribution
is made to the auto-balance mechanism by the rear. We have now considered balance
in a straight line, but as we lean when cornering, there must be other factors
at work to maintain equilibrium under these conditions.
STEERING (CORNERING).
To analyse this, we can divide it into two phases;-1. Initiating the turn,
2. Maintaining the turn.Since the second phase is easier to analyse, let's look at it first. It is
not feasible to steer a motorcycle through a corner in a substantially upright
position, as in a car or side-car outfit, because the centrifugal force generated
would cause it to fall outward. Hence we must bank the bike inward so that this
tendency is counteracted by the machines weight tending to make it fall inward.
opposing moments, the one due to centrifugal force acting outward, and the other
to gravitational force acting downward (both acting through the C.of G.). The
actual angle, which depends on the radius of the turn and the speed of the machine,
is that at which the resultant of the two forces passes through a line joining
the front and rear tyre contact patches. This is the steady-state roll axis.
But how do we actually initiate the turn - do we lean or do we steer first?
Let's see what happens with each method. If we turn the handle-bar in the direction
in which we want to go, both centrifugal force and the front wheel precession
would cause the bike to topple outward, and that leads to gravel rash. But if
we momentarily try to turn the bar quickly in the opposite direction, (sometimes
known as counter steering) then these two forces will combine to bank the machine
to the correct side. Gravity will then augment the banking effect and this,
in turn, will give rise to gyroscopic forces helping to steer the front wheel
into the curve, whereupon the processes for maintaining balance as described
above take over and keep the bike on our chosen path. This is all very well,
I hear you say, but if this is the way to corner, how come we can steer a bike
no-hands. Well, it certainly is possible to do so, but only with a lot more
difficulty. Precise control and tight turns are difficult to accomplish without
handle-bar manipulation. Just try it! Let's consider the no-hands situation.
As we saw earlier, simply banking the bike steers the front wheel in the correct
direction automatically, through precession. But how do we make the bike lean
in the first place, what do we have to push against? There is nothing solid
to push against and so the only way to apply bank (without the facility of steering),
is to push against the machine with the inertia of our own body. This means
in practice, that in order to lean the bike to the right, we must initially
move our body to the left. So now we have two possible methods of initiating
a turn, and it is interesting to note that in both of them (banking and reverse
handle-bar torque) our physical effort is in the opposite sense to that which
might be thought natural, but when learning we adapt quickly and the required
action becomes subconsciously automatic. It is these reverse actions that require
us to learn to ride in the first place, when learning most of us wobble about
out of control until our brain latches on to the fact that counter-steering
and counter-leaning is the way to do it. Once the brain has switched into reverse
gear, it becomes instinctive and is usually with us for life, and we could return
to riding after a long layoff with no need to relearn the art of balancing or
steering. So which of these two possible methods of initiating a turn do we
use in practice? We probably subconsciously combine both methods, and the pressure
on the inner handgrip is partly forward (counter-steering) and partly downward
(banking). Remember though, that the actual counter-steering movement is very
small, since gyroscopic precession depends for its strength on the speed of
movement not on the amount of movement. If you still don't believe that steering
to the opposite side works, then next time you are out riding, try jerking the
bars quickly to one side, and see what happens. Leave yourself plenty of road
if your reactions are a bit on the slow side. Do this at about 40 mph., and
don't blame me if you fall off. The relative proportions with which we combine
the two methods depend partly on riding style but also on speed and machine
characteristics. For example, a heavy machine with light wheels at low speeds
demands a different technique from that applicable to a light weight machine
with heavy wheels at high speeds, and hence the two machines will have a different
feel. But humans adapt quickly and the correct technique soon becomes second
nature. It may seem strange that in the above discussion no mention has been
made of such important parameters as, steering geometry, wheel and tyre size,
wheelbase, frame stiffness and so on. This is simply because, balance and the
ability to start and maintain a turn can be achieved within a wide range of
these parameters. That is not to say that these factors are unimportant. We
shall now look a little more closely at one of the more important parameters
that come under the heading of steering geometry, i.e. TRAIL. Consider first,
which shows the basics of steering geometry.
TRAIL.
The primary function of this, it is often said, is to build in a certain amountof straight line stability, in addition to that obtained by precessional effects
as described above. But trail also introduces other effects which are vital
to the feel and handling of the motorcycle.
If the wheel gets displaced from the straight ahead position, i.e. the wheel
is at an angle to the direction of travel (slip angle is the technical term),
a force at right angles to the tyre is generated. Since the contact patch is
behind the steering axis (positive trail) then this force acts on a lever arm
(approximately equal to the trail) to provide a correcting torque to the angled
wheel. That is to say, if the steering is deflected by some cause e.g. uneven
road surface, then positive trail automatically counter-acts the displacement
and gives a measure of directional stability. However, as shown earlier, we
cannot just consider any steering effect in isolation, gyroscopic forces must
be considered also, suffice to say, at this stage, that in this case trail and
precession work in harmony to keep us on the straight and narrow.
is much greater than that of the front, the rear wheel is the more important
in this respect. The reverse is actually the case for several reasons.
Imagine that the contact patch of each wheel is, in turn, displaced sideways
by the same amount (say ½ inch.). The front wheel will then be turned
by approximately 7-10 degrees (depending on the value of trail) about the steering
axis, this gives rise to a slip angle of the same amount and generates a sideways
force that has only the relatively small inertia of the front wheel and forks
to accelerate back to the straight-ahead position. But the slip angle of the
displaced rear wheel will be much less (about ½ degree) and so the restoring
force will be reduced accordingly, but this also has to act on the inertia of
a major proportion of the machine and rider, hence the response is much slower
than is the case with the front wheel. From this, we can see that increasing
the trail as a means of increasing the restoring tendency on the wheels is subject
to the law of diminishing returns. It must also be emphasized that the distubance
to a machine's direction of travel, due to a sideways displacement of the tyre
contact patch, is less from the rear wheel than the front because of the much
smaller angle to the direction of travel that the displacement causes. To summerize,
while the large trail of the rear wheel has a relatively small restoring effect,
the effect of rear wheel displacement on directional stability is also small,
and hence compensates. As mentioned before, trail has effects other than directional
stability, let's look at a couple of the more important ones.
If we lean a stationary machine to one side and then turn the handlebars, we
find that the steering head rises and falls depending on the position of the
steering. In motion, the effective weight of the bike and rider supported by
the steering head, is reacted to the ground through the tyre contact patch.
This force tends to turn the steering to the position where the steering head
is lowest (i.e. the position of minimum potential energy). For a given amount
of trail, this steering angle is affected by rake angle and wheel diameter,
one reason why different size wheels feel different, if all else remains the
same. As long as we have positive trail, as is normal, then this turning effect
is into the corner. Thus the amount of front wheel trail affects the amount
of steering torque that the rider must apply (hence the feel of the steering)
to maintain the correct steering angle consistant with the radius of the turn
and the bike's speed. Some bikes seem to need to be held down into a corner,
whilst others need the opposite approach. This is also influenced heavily by
tyre characteristics, but that will have to wait for another occasion.
As we all know, even when we are riding straight ahead the steering feels lighter
on wet and slippery roads than on dry. This is because as we have seen, our
seemingly straight line is actually a series of balance correcting curves, with
the handlebars turning minutely from side to side all the time. Also as we have
seen, a small steering displacement produces a slip angle, which causes a restoring
torque. For a given slip angle, this torque depends on tyre properties, surface
adhesion and trail. On slippery surfaces the correcting torque is less, thus
through the handlebars, we get a feedback (dependent on trail) for the amount
of grip available. A bike with only a small trail value may give too much of
a sense of slipperiness in the wet, and give the rider a certain degree of apprehension,
whereas on the other hand, a large trail, under these conditions, may give out
a feeling of security, which can easily engender overconfidence with predictable
results.
Tuesday, April 03, 2007
Classic Car Show Power Voting
Classic Car Show Power Voting
by: Ray Taylor
I received a call from a very nice lady after our last event. She was concerned and confused. She was concerned with the number of trophies won by Clubs. She was also confused as to how club members seemed to win a majority of the trophies. I then explained Power Voting to her. Here's what I said.
Power Voting is when all the group/club members vote for all the other club members in the show. This almost guarantees the club will have lots of winners. The reason that this small group of 10 to 30 club members can sway the results is the same reason we end up with lousy politicians Apathy!
Not voting puts the results in the hands of a few rather than the many. Power Voting would be ineffective at Car Shows if a majority of the attendees would take the time to check out the cars and vote for their favorites. If the General Public would just do that, then Power Voting would be of little consequence. But if the General Public doesn't want to be bothered with voting, then Power Voting can absolutely affect the outcome of the trophies awarded.
I know some of you are thinking, "Why not have trophy classes? Won't that help?" We tried having trophy classes for years. It just didn't work and was really unfair to some. One time we would have dozens of cars in the Street Rod Class, then the next time only a few. This was true for almost every show where we had classes. One class would be overloaded and another under represented. Then when we changed things, the problem still existed only in different classes. We felt like a dog chasing its tail trying to keep the classes balanced. It just didn't work. So now we do a People's Choice Award system: if the people like your ride AND they vote for it, you win! The best ideas are always the simplest: get the most votes, and you get Best of Show. This has resulted in the usual outcome, like the Low Rider Bike winning Best of Show in January. The people loved his bike, and he got the most votes so he Won! It's that simple.
For our part, we will continue to ask people to take a ballot and vote for their top 10 favorite vehicles. If they don't, then groups/clubs will control the outcome of the People's Choice Awards at any Car Show. Please do your part, come out on Monday, Memorial Day, May 28 to the next San Diego Car & Cycle Show & Swap at the Q and VOTE!.
See Ya There!
Ray Taylor
Owner of the San Diego Classic Car & Cycle-Show & Swap
and Classic Cars Net Free Classifieds
by: Ray Taylor
I received a call from a very nice lady after our last event. She was concerned and confused. She was concerned with the number of trophies won by Clubs. She was also confused as to how club members seemed to win a majority of the trophies. I then explained Power Voting to her. Here's what I said.
Power Voting is when all the group/club members vote for all the other club members in the show. This almost guarantees the club will have lots of winners. The reason that this small group of 10 to 30 club members can sway the results is the same reason we end up with lousy politicians Apathy!
Not voting puts the results in the hands of a few rather than the many. Power Voting would be ineffective at Car Shows if a majority of the attendees would take the time to check out the cars and vote for their favorites. If the General Public would just do that, then Power Voting would be of little consequence. But if the General Public doesn't want to be bothered with voting, then Power Voting can absolutely affect the outcome of the trophies awarded.
I know some of you are thinking, "Why not have trophy classes? Won't that help?" We tried having trophy classes for years. It just didn't work and was really unfair to some. One time we would have dozens of cars in the Street Rod Class, then the next time only a few. This was true for almost every show where we had classes. One class would be overloaded and another under represented. Then when we changed things, the problem still existed only in different classes. We felt like a dog chasing its tail trying to keep the classes balanced. It just didn't work. So now we do a People's Choice Award system: if the people like your ride AND they vote for it, you win! The best ideas are always the simplest: get the most votes, and you get Best of Show. This has resulted in the usual outcome, like the Low Rider Bike winning Best of Show in January. The people loved his bike, and he got the most votes so he Won! It's that simple.
For our part, we will continue to ask people to take a ballot and vote for their top 10 favorite vehicles. If they don't, then groups/clubs will control the outcome of the People's Choice Awards at any Car Show. Please do your part, come out on Monday, Memorial Day, May 28 to the next San Diego Car & Cycle Show & Swap at the Q and VOTE!.
See Ya There!
Ray Taylor
Owner of the San Diego Classic Car & Cycle-Show & Swap
and Classic Cars Net Free Classifieds
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