Electric Bicycle Road Racing Theory

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Electric Bicycle Road Racing Theory

The idea of this thread is to start with some basic principles and realities and build the sport of EBRR up from the roots. Along the way I will attempt to recreate existing arguments about electric bicycles that seem to recur regularly. This is to be made as a sort of college course... even though it's not really going to be taught anywhere. (well, you never know, I can remember some college courses at about this same level)

Physics

We begin with a review of bicycle physics.

An ordinary human being can (at best) produce 400 watts of power over a sustained period by pedaling. For short durations it's possible for peak athletes to achieve 750 watts of power going out the rear wheel. At about 30 mph the primary losses are due to air resistance, so it's very difficult to go faster than 30 mph by pedal power alone in an upright bicycle.

The electric bicycle was created as a "bicycle" replacement or enhancement. In order to retain a definition of "bicycle" we need to accept that motor power cannot significantly exceed human power. This sets a realistic upper limit of 750 watts (1 hp) as the boundry.

The first major point is that even BEFORE we look at the laws pertaining to electric bicycles we are already more or less bound to a limit of 750 watts simply because it what makes us within the definition of a "bicycle". Going significantly above this level and you are into motorcycle or moped territory.

Present Laws

Europe - 250 watts output
Canada - 500 watts output
USA - 750 watts output

The USA is allowing the logical maximum for a "bicycle" while the other nations seem to cut the limit down to something less than is within the accepted understanding of a "bicycle". This is unfortunate, but what we have to work with.

Since we are discussing "pure forms" in the abstract and we see that in the most pure sense 750 watts is the logical limit for an ebike we simply state that 750 watts is the "proper" level to establish as a worldwide standard for Electric Bicycle Road Racing. Since racing would be done on Go Kart tracks and these are not regulated by street laws there is no reason not to set the level worldwide as 750 watts. (that way in the future if you have the World Cup equivalent of EBRR then everyone is using the same limits)

So the "bottom line" is that laws exist and some are compatible with racing while others are not. In the USA it should be easier to produce machines that can be used on the street as well as the track, but in much of the world these machines would be sold as "off road only".

Motor Input verses Output

We know that at tax time we report our income and then deduct certain things before we actually calculate our taxes. Motor Input verses Output works the same way. Laws are written to limit the "Output" of a motor, but make no reference to what "Input" was required to get there.

A typical motor is about 75% efficient. This means that if you start with 1000 watts of Input power that you will get approximately 750 watts of real Output at the rear wheel.

Given the physics involved and also that fact that it's nearly impossible to limit Output directly (it's always something that is arrived at "after losses") the logical way to organize racing is around an Input side restriction.

So if we want approximately 750 watts Output, then we limit the Input to 1000 watts and we simply allow that through the process of motor losses we arrive at the desired result.

This is a critical insight, because if it's possible to electronically calibrate the precise amount of power going INTO the motor we can have a class of racing that is fair. With a simple meter on the Input it's possible to define a class of racing very tightly.

1000 watts of Input is the logical definition of EBRR.

Other Arguments

It's always important to review each and every other argument for how to organize racing classes.

Unlimited Power

The most natural urge is to want to allow Electric Bicycle Road Racing to use as much power in the motors as the designer can achieve. On the surface this even seems like a good idea until you start to anticipate where the designs will naturally progress. If you can increase motor power on an unlimited basis you will also need to increase battery capacity to feed this higher power level. More battery means more weight and that means a stronger frame and possibly suspension to make it usable. At some point the machine resembles a motorcycle only it retains "faux pedals" to satisfy the bicycle definition. An acronym PINO (Pedals In Name Only - "Pee No") describes this type of machine.

The next logical step is to limit the overall weight of such an overpowered machine so that a limited battery weight places a self induced restriction on effective power usage. Let's say the bike is limited to 100 lbs overall. You now have a situation where a 150 lb racer has a 50 lb advantage over a 200 lb racer because the bikes are limited to a fixed amount of weight.

In order to still try to salvage this approach you have to figure out some sort of indexed relationship of power, body weight, and bike weight to equalize things. It simply gets too complicated and no one will perceive it as being fair.

With a 1000 watt power restriction the rider's pedal strength will tend to match their weight (if they are athletes) so the heavier rider can compensate by being stronger. This nullifies weight differences during accelleration. (though when it comes to top speed aerodynamics the smaller rider probably glides better)

Battery Capacity Limits

Another approach to equalizing the racing is to set a limit on the battery capacity without regard to it's physical weight. This allows all the bikes an equal overall quantity of power but alters the way people will operate their machines in a race. Rather than an all out sprint where the racer applies full throttle whenever they can the Battery Capacity Limited racing will favor those with a smoother riding approach so that less energy is wasted getting around the track. While we can applaud the ideal of increased efficiency, if the effect is to take the passion from the racing experience the psychological negatives tend to make this less attractive. However, there are special cases where this could make sense. (fragile streamliner recumbents for instance)

To date these are the main alternative approaches to ebike racing.

Public Perceptions

There are several broad categories of people that have fairly clearly defined perceptions and opinions about ebikes.

The Cyclist

The pure cyclist simply will not allow a single thought towards electric bikes because it's a violation of everything that the cyclist holds dear.

The Senior Citizen

Many Senior Citizens view the electric bike as a "mobility device" for those who are by now too frail to get around under their own power. In this view the electric bike is a sort of wheelchair. This person will guard the low speed image of ebikes and oppose anything that gives a racing perception.

The Outlaw

The outlaw is someone that knows the laws on the street, but just completely disregards them in favor of whatever power they can achieve by their own bike modifications. When presented complicated issues about how high powered ebikes fit into the larger scheme of things their response is "I do whatever I can get away with." This person might race, but possibly in some other racing category. To the outlaw having a 1 hp power limit seems confining.

The Parent

If you are shopping at WalMart for childrens toys you will come to realize that within the store bicycles are classified as "toys". They sell some electric "toys" such as scooters, pocket bikes and even ebikes. The parental perspective is that ebikes are more or less silly toys that you get your child for xmas, but that they will grow out of them quickly so you shouldn't pay too much or worry too much about quality. The parent will be a little worried about something that appears too fast, so the 1 hp power limitation will provide some comfort to help them decide to purchase an EBRR bike for their child.

...the target demographic for Electric Bicycle Road Racing begins at about the age of twelve and fades out at about thirty much the same as in BMX. (this isn't to say that some older folks might not like it too)

The Passion

What will make Electric Bicycle Road Racing unique?

Cycling already provides numerous excellent racing styles that demand athletic performance of their racers. Motorcycle road racing already gives the rider skill thrills of riding at the edge of traction.

Part of the reason that newer sports like Mixed Martial Arts have taken hold is that they took the best of several other sports and blended them into something that brings out the best of all of them. That same mindset needs to be used in EBRR in that the top level racers need to have mastered all elements of the sport to succeed. There can be no room for the out of shape racer if EBRR is to be considered a real sport.

Walk Through A Race

Let's walk through a typical race...

At the start riders are lined up in rows of two (ideally) based on heat races or best lap times which were decided in advance. The faster riders are placed at the front. To get a fast start the rider needs to stand up and pedal explosively off the line because below 30 mph aerodynamic effects are small. Once the rider gets up to about 25-30 mph it makes sense to drop down onto the seat and tuck behind the fairing to increase top speed to near 40 mph. This is taking place on a Go Kart track that isn't going to allow top speeds for very long, so just as you are hitting your top speed you quickly need to brake for the upcoming corner. In the corner you ride the very edge of traction and both tires may drift a little. Depending on how much speed you lost in the corner you would either stay in the tuck and use all motor power or you might stand up again and get another burst of pedal power.

Different Go Kart tracks are going to stress different racing styles as the tighter tracks will reward more frequent bursts of acceleration coming out of the turns while other faster tracks will reward more time in a tuck for faster top end speed.

Drafting will be a big factor in this sport as it is in Cycling because at 40 mph the aerodynamic wake is much larger than at the 30 mph level that most Cyclists are used to. This means that the rider in second place on a straight away will almost always have passing power coming into the next turn. This means that the racing will be very intense with a lot of chances for passing.

At this point it's important to bring up the notion of "fair play".

You simply cannot allow dirty tactics into a sport like this because it's simply too easy to disrupt another rider and cause a crash. While in many cases the dirty rider goes down with the innocent anyway the sport suffers if there is no authority to penalize foul play. Riders should be stripped of any win if they intentionally cause another rider to crash and if they repeat that behavior that rider should be banned from the sport.

Penalties

What about doping?

I don't think that doping would be a big issue in this sport. Even if some guy is using steroids it will only benefit in the acceleration portion of the sport and that is not so dominant as to make for instant success. While there might be problems down the road with doping it doesn't seem important for now.

Electrical Cheating?

There will be an absolute need for precise power limiting circuitry to ensure that no one exceeds the 1000 watt input limit. Anyone caught tampering with the circuit (which needs to be supplied by the racing organization) would get an instant penalty of some sort. For the early days of the sport there will be the need to accept less precise limiting techniques (like just using known 1000 watt controllers) but over time that will need to be made more strict to ensure fairness.

Distance and Duration

The length of the race needs to be compatible with the amount of battery that is used. We calculate battery size:

Power input restricted to 1000 watts per second = 1000 watt / hour (Wh)

So if the race lasted a full hour at full throttle you would need a battery that was something like 48 volts and 21 Ah. In order to lower the battery requirement it would be preferred to shorten the race to about half an hour which would drop the battery required to:

1000Wh / 2 = 500Wh

...and this can be achieved with a 48 volt and 11 Ah battery.

Lead Acid (SLA) ~ 50 lbs (Peukert's Effect requires 20Ah)

NiCads ~ 30 lbs

NiMh ~ 20 lbs

LiFePO4 ~ 15 lbs

Assuming:

Rider ~ 175 lbs

Bike ~ 55 lbs

SLA = 50 / ( 55 + 175 ) = 22%

LiFePO4 = 15 / ( 55 + 175 ) = 7%

As long as the race duration is kept low the battery is reduced in it's influence on the race outcome. However, just like with being overweight the more athletic rider and the lower weight battery will have an advantage. As with Cycling the quest for lighter and lighter machines will guide technological progress in the sport, but the shorter distance will tend to place a cap on battery costs. The sport needs high technology, but should not only be about technology.

How far is half an hour?

We assume that the average speed is about 30 mph. Half of 30 miles is 15 miles so we calculate that the maximum distance should be LESS than 15 miles.

A realistic track length would be 10-15 miles.

A realistic race duration would be 20-30 minutes.

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Electric Bicycle Racing With Battery Capacity Limitation

I actually talked with the sponsor of this event and suggested using a 1000 watt input limit, but this group is primarily made up of streamliner recumbents and they really can't attack the corners safely. Because of this, the choice went to Battery Capacity Limiting instead. However, the sponsor did listen to me when it came to the motor power and set a 1000 watt limit on the motor:

HPC - ePower Events

Non metered racers will further be limited to a system with a maximum 1000 watt continuous rated motor.

They use standard wattage meters like the WattsUp meter and after the race if you go over your limit of watts they penalize your score. It's more of an individual time trial. This is not a PINO sport however, and pedaling helps a great deal in assisting the motor since they give a rather small wattage limit given the distances.

So if you are interested in this type of racing you should follow that link for more information.

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Electric Bicycle Road Racing With Unlimited Power

The "Death Race" is an "Outlaw Culture" race for 50cc gas powered motorized bikes. Electric Bikes have essentially "crashed the party" and are making efforts to get involved. The electric bikes are strictly PINO (Pedals In Name Only - "Pee No") and can have Unlimited Power. These machines are not even close to being street legal.

Death Race 2010

If you aren't an "Outlaw" don't even bother!

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Electric Bicycle Road Racing With 1000 Watt Input Limit

That's why it's a "theory" thread.

Hopefully I'll be posting information of upcoming races for the 1000 Watt input class someday. What is needed is a "Cycling Culture" as a base because EBRR should be a sport for athletes, but it also requires a willingness to look at electric power as a sort of bionic extension of human power. On VERSUS when they covered the Tour de France they talked about worries that small 200 watt motors might be hidden in frames and apparently they even xrayed some bikes to check for it. So the idea of electric assisted racing is "in the air" but the actual racing implementation is fractured into different subcultures.

The EBRR scene is at present "Balkanized".

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The Cyclists View

ES: Veloman

Ebike racing would be cool, but it won't ever be as big as road cycling racing or motorcycle racing. It's an efficiency sport that includes a motor- hence it is just a fringe activity at best. With road cycling, it's all about athletic performance (and efficiency is demanded). With motorcycle racing, it's all about technique and high power/speed.

The general public has essentially no interest in watching a sport that isn't the pinnacle of either athleticism, power, or skill.

Ebikes are just sooo practical - that they don't hit those psychological highs that other activities can create. Think of the thrill of going 150mph on a streetbike, the thrill of setting an athletic personal best, or outskilling an opponent at a game of baseball, tennis, and so on.

I think a lot of people who drive and love cars - they shun the idea of transporting themselves at a max of 30mph because it's boring or something like that. They love the idea that they can drive 0-60 in 6 seconds in a 'sport' car, thinking it's thrilling. Yet they are really just fooling themselves because in the end, they are still no where near the pinnacle of speed and power that motors can achieve.

I, on the other hand, love the fact that I know I can pedal my road bike faster than 99.99999% of any human. That's a lot more rewarding, even though I may only go 30mph up that hill, while a Mustang driver could do 80 up it.

This is an excellent observation of why EBRR is getting Balkanized. For the other sports (Cycling or Motorcycle Road Racing) they play to the extremes of either athleticism or raw speed and the design goals emerge naturally. The EBRR classes that have developed have a sort of cult like design strategy where people clump together based on their own interests. Recumbents want to race other recumbents, so they make rules to serve that agenda. Outlaw ebikers with PINO bikes want to race other Outlaws so they mold rules for themselves.

1000 Watt Input Limiting EBRR tries to lure the Cyclist back into the sport. The attempt might never work for the very reasons that Veloman has stated, that part of the Cyclist "pride" is that they have in effect done it themselves.

Lance Armstrong even titled his autobiography:

"It's Not About The Bike"

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Some BMX History...

Check out wikipedia:

BMX racing - Wikipedia, the free encyclopedia

Other notable American sanctioning bodies

Along with the majors and pioneers, there were other BMX governing bodies, both national and regional and past and present. Among them were the Bicycle Motocross League (BMXL); the United Bicycle Racers Association (UBR) (1977-1983); the United States Bicycle Motocross Association (USBA) (1984-1986), which merged with the ABA at the end of the 1986 racing season after financial trouble made it unsustainable; the International Cycling Association (ICA), which was started in part by professional racer Greg Hill in 1990; and the Southeast Region-based National Pedal Sport Association (NPSA) (1975-1985). They are all gone now, but they did make, for good or ill, an impact on the American BMX scene.

My comments:

Apparently the beginning of BMX was at least as fragmented as the beginning of EBRR. While BMX seemed to have a single definition of what the bike would look like they still managed to create multiple racing organizations where many did not survive.

As I've pointed out in previous postings EBRR is already divided into at least four classifications now:

Battery Capacity Limiting
Unlimited Power
Unlimited Power - Lite (weight limited)
1000 Watt Input Limited (Federal Ebike Law)

...so if history is our guide chaos at this stage of the process is normal. The very fact that so much chaos exists means that there is interest so we should see it as a positive sign.

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The Big Picture

What is the purpose of EBRR?

Is it racing?

Actually No.

The real reason behind the creation of a sport like EBRR is to create a new set of products that will be bought by millions of people.

What?

I thought that racing was about passion and EBRR was going to be the new Mixed Martial Arts of bike racing and ESPN and VERSUS were going to one day put shows about it on the air.

Well, those are true... I would hope all that happens... but the real reason to have the excitement in the sport is so that people will want to buy the product and find a means of transportation that does not use gasoline. The racing is in effect just the advertising for the product to give people something fun to connect with. Most people that would buy an EBRR bike would just ride it around the neighborhood and get to a friends house or run an errand.

The deep secret of EBRR is that it's supposed to be "practical" as well as fun.

This is why it's so important to keep it legal. If the racing rules are so different from the street rules then no one will buy the product because no ordinary person wants something that is only usable on a racetrack.

The bigger picture is about mass production.

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Rich Man's Hobby, Poor Man's Disease

It's said that:

"Racing is a rich man's hobby and a poor man's disease."

Many people who are rich are that way because of inheritance. Since the "fun" of making money is not really available to them (daddy made the money long ago) they need some other outlet for their passions and so racing is an avenue for the "idle rich" to find pleasure.

For the poor it's a matter of misdirection. The poor "should" read the bible, learn self discipline, and then apply themselves in the "real world" of business so that they can get themselves out of being poor. When a poor person chooses racing as a hobby this is a sickness and a misdirection of where they should actually be directing their passion. For the poor racing is like an addictive drug.

The "healthy place" for racing (like with Electric Bicycle Road Racing) is as a passage from youth to adulthood. The same competitive energy that one channels on the racetrack is then passed along to later life when one gets into business.

Racing "should" build positive morals as it teaches that greed and fear are always in balance. Too much greed for speed at the wrong time and you crash. Racing done right teaches the American culture of honest free enterprise and self reliance which are positive traits.

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Sad Demographic Realities

America is obese... and it's not just adults, but even the children are obese. In the Southern states it's worse because of the weather, but across all the states people have gotten fatter recently.

Ebike riders tend to follow the national trends and are often even worse off as many take up the hobby because of advancing age or poor health. Overall the base demographic to draw from for a sport like EBRR is pretty grim.

Cyclists are abnormal because they buck the obesity trends and so they are actually the ones who best represent the future of any kind of athletic sport. Cyclists who would consider electric assisted racing might be rare though.

The core "problem" as I see it now is that if you expect any type of racing to emerge "organically" from out of shape Americans that it will tend to mirror the trends of those that are into ebikes now.

Unhealthy people will want sports that unheathly people can do.

So I'm aware of the disconnect between present reality and "ideal" future reality. The present unhealthy demographic is not very good raw material to get anything started.

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Business is always Conservative By Nature



Shimano Steps

Shimano unveils Pedelec Motor with Long-life Battery - ExtraEnergy.org

When Shimano made the corporate decision to get into the electric bike motor market they did so in the most conservative way possible. Their Steps 250 watt motor is the lowest common denominator across the worlds legal standards. In the US you are allowed three times as much power, but if Shimano chose to build a 750 watt electric bike motor they would be limited to sales in the US.

This should make us think...

If EBRR is to be a success you can't expect major corporations to fund the mass production if they perceive the investment as "risky". Any EBRR racing class that goes above 750 watts (1000 watt input) is going to alienate the world of mass production and the real people that lose out is the general public.

Business is conservative, it will never support racing that can't be sold anywhere.