* * * Aerodynamics * * *

[Lowell]

Somehow I doubt most e-bikers worry about being able to control slides in corners...

 

[safe]

I was seeing it like this:

Well it's definitely an even tighter tuck. My only concerns would be like the previous posting about "King" Kenny Roberts. Which is going to be safer at high speeds? My guess is that the knee pad approach takes away from the ability to "react" to events to a small degree.

Let me give you a short lesson on that...

The "racing posture" is to have your shoulders FLAT or at least partially IN OPPOSITION to the direction of the turn. The reason is that you can quickly "shift" your sholders and it produces a rotational torque that counters the slide of a tire. The knees (knee dragging) are also used as a sort of "balance pole" to help correct your balance when needed.

Wow, truth is that very, very few people get good enough to know proper form and so they crash for many circumstances that they could have survived.

Bottom Line: For safety reasons (being so high up) I'd "advise" the traditional "road racer" posture over the "Gravity Bike" posture. Don't forget... those guys are REALLY low to the ground.... REALLY low.... so they are dealing with different weight balance issues...

 

[safe]

Somehow I doubt most e-bikers worry about being able to control slides in corners...

They don't because they are too slow to have to worry about it. My point is that when you start to go faster things like "center of mass" and "riding position" can't be overlooked or you will crash and burn very quickly when you encounter your first danger...

I'm "safe" you understand... I ride like a maniac... but I do everything possible to give myself an advantage so that I don't become a victim.

http://www.norfolkarena.co.uk/powerslide/goldplus.htm

 

[Geebee]

Safe, if you want a real blast try a low recumbent trike around a tight corner at speed, the trick is to get your upper body over the side of the trike so that your head is almost level with the curb (to prevent it flipping and helmet please) and then if you are going fast enough you will induce a 3 wheel drift or slide, great stuff.

 

[safe]

Three wheeled bikes are like go-carts. They are very stable.

Comparing two wheels verses three or four is sort of the "apples verses oranges" thing though. Comparing a recumbant to a road racer style (tight tuck, not the upright bikes) is a better comparison because they both have good aerodynamics and yet they differ in handling behaviors. It seems like a two wheeled recumbant would have no "counter measures" if one of the tires started to "drift" at speed. I've never seen a recumbant "in a drift" but maybe it can be done.

Anyone ever done a "powerslide" on a recumbant?

Every 14 year old boy and his bicycle has done a "powerslide"... (or at least a looooong skid sideways with a little bit of crossup)

 

[Anonymous]

Safe,

Actually, I find it far easier, safer, and faster to slide on a recumbent 2 wheeler than on an "upright" one. Powersliding? Piece of cake.

One thing that was weird to learn was leaning my inside leg into the corner so that my outside thigh was just about to graze the ground. It is much more comfortable and forgiving than the kneecap for obvious reasons.

A recumbent is far less pitch sensitive than an upright bike - so sliding either end is not likely to grip and fling the rider (high-side). A recumbent doesn't need the theatrics (hanging off, etc) that upright bikes need to get into and out of a corner due to the lower CG and resulting reduced polar moment about the longitudinal axis.

There also isn't a body of experience to draw on regarding recumbent stability and control in a roadracing environment. Yet. So I had to find out for myself and the results have been very satisfying.

 

[safe]

Actually, I find it far easier, safer, and faster to slide on a recumbent 2 wheeler than on an "upright" one. Powersliding? Piece of cake.

I've never seen a recumbant do anything serious in a performance "handling" sense. While your conjecture that a lowered center of gravity somehow makes a bike less likely to high side is "interesting" is has nothing to do with the way things really work.

A history lesson...

In the old days of motorcycles they had very "pointy" tires. The logic then was that when you leaned onto the sides the tires could stick better. The frames were actually designed to flex so that the tires NEVER broke loose. As a result, if the tire did brake loose you were almost guaranteed a crash.

The newer thinking is that you use more flat shaped tires and when you lean you ride on the edge which gives a more sensitive feedback about when the traction is getting light. The big change in frame design was to eliminate the flex out of the frame so that when the tire started to slide and then "caught" itself the frame would not hold that stress like a "spring" only to a short time later "unwind" and give you a "high side". The "high side" is really a "frame flex" issue and not a center of mass issue. (hint, hint, a "pointy" tired recumbant with a flexible frame should "high side" exactly the same way) This is when the "Delta Box" frames started showing up that really lowered the flex and thus reduced high sides significantly. (they still happen, but you really are just as likely to low side as high side these days)

When someone is in a recumbant position they lack the ability to "throw their weigh around" like you can in a jockey position. So I'm just trying to find the "magical" physics that makes your theory valid. What body part can you twist, turn or "whatever" to get rotational torque like you can with the knees and shoulders on a road racer? The head alone makes a bad "counter balance" because it messes with your inner ears sense of balance. On a motorycle you keep your head level, shoulders flat and bend everything else. Where's the "counter balance"?

I think there's a reason that you have never seen any serious "handling" performance out of recumbants. (they are not at the race tracks to my knowledge) At the level of actual competition I don't think that a recumbant would fair very well, the handling limiting the rider to well below the traction limits of the road racer. At 100 mph I would much rather be riding "on top" of something than sitting and having to pray that the tires don't let go and crash and burn.

 

[safe]

At the wikipedia website they have a very favorable opinion of the recumbant trike:

"Three remarkable characteristics of recumbent trikes include: 1) the fact that the rider does not need to disengage from the pedals when stopped; 2) the trike can be geared very low to enable mountain climbing while heavily loaded and at a slow speed, without losing stability; and 3) trikes are capable of turning sharply without leaning, producing lateral "g forces" similar to sports cars. Recumbent trikes may also be more suitable for people with balance or limb disabilities."

...but they seem less enamored with the performance of the two wheeled recumbant:

"Balance. Balance is easier to effect with a higher centre of gravity, because of the "pendulum effect" (it is easier to minutely change the angle at which ordinary bicycles lean).[2] The lower center of gravity makes two-wheeled recumbents harder to balance, especially when moving slowly or on unstable surfaces. If a wheel slides, the bike will typically go down very fast. Where one can change one's weight from the seat to the pedals on an ordinary bicycle, one's weight is only on the seat while riding a recumbent. This ability to shift one's weight and place weight on one's feet is an important part of the difference in balancing an ordinary bicycle and balancing a recumbent. Maneuverability. Recumbents have usually a larger turning radius. Also, it's impossible to jerk the front wheel up curbs. Since the front wheel is usually small, driving up unlowered curbs is very risky even with suspension."

http://en.wikipedia.org/wiki/Recumbent_bicycle

A comment on this, on my lead acid bike I placed the batteries very high up in the air, but the effect is that it makes the steering LIGHTER than if I had placed them down low. A bike steers about the center of mass and so the FURTHER the tires are from the center of mass the MORE responsive it is. (more torque to rotate the mass) I know, it sounds "crazy" but that's how bikes actually steer... weird huh?

The irony is that people think that a lowered center of mass is "good" when in reality it's the opposite... one gets the best handling with a center of mass that is higher... it's just the weird physics of bicycles... (that's why those scooters with the low mass handle so bad... it's for the same reason... kind of reminds me of the old "bikers" verses the "mods" debates back in the 60's)

The recumbant trike looks like the winner... (if I had to pick)

 

[Anonymous]

I used to do lots of sportriding - and spent a day at was once called Sears Point. I've owned and built a number of sport bikes. And enjoyed them a lot. There are some great roads near Cloudcroft, New Mexico, near where I used to live. Heck, here's my old RZ between Cloudcroft and Ruidoso:

http://i19.photobucket.com/albums/b157/rohorn/rz350.jpg

That you haven't seen or experienced anything regarding the performance potential of the recumbent configuration is the result of your lack of knowledge on the subject. I've BUILT some motorized recumbent racetrack bikes - they work. They are far less sensitive to tire profiles. I've done a lot of testing.

As far as crashing and safety goes, virtually all the injuries come from the initial impact with the ground - something speed has nothing to do with. But losing control with your butt 2 inches off the ground is downright comfortable compared to being flicked off of a 30" high seat. I've done both.....

The whole throwing the body or body parts to control a road bike was pure BS in my opinion - and has been proven:
http://www.superbikeschool.com/machinery/no-bs-machine.php

Current racing design is about selling what's in the showroom this year - and going with what is familiar to the tuners and riders. Kenny Roberts is a legend - one who I admire a lot (as one should be able to discern from the above picture), but his old racing style is very much obsolete. You don't see too many flattrackers making it into GP anymore - there's a reason for that. There's also a reason why laptimes have pretty much stagnated for the last 20~ years with only microincremental improvements (due to tires and engine management) - the dynamics of the basic roadrace bike design has resulted in a developmental dead end.

Which is why I'm messing with recumbents. I'd rather develop what's next than consume what's yesterday. In the mean time, a lowracer recumbent is the fastest configuration for a low powered electric bike - arguing otherwise is just so much grumpy old man BS.

NOBODY is powersliding a 1000 watt bike at 100 mph and highsiding it anyway.

 

[Anonymous]

The irony is that people think that a lowered center of mass is "good" when in reality it's the opposite... one gets the best handling with a center of mass that is higher... it's just the weird physics of bicycles...

There's a big difference between what makes a bike easier to ride at low speed and what makes one faster on a racetrack. Scooters and motorcycles have vastly different high speed characteristics as a result of the different wheel sizes and wheelbase, not to mention terrible suspension. Build a motorcycle with scooter wheels, wheelbase (but with a motorcycle CG) and nasty suspension and you'll still have a squirly motorcycle.

The higher the CG, the more the front tire has to steer to deviate the path of contact to attain the desired lean angle. Or it attains the desired lean angle later with the same steering angle. And at high speed, the limiting factor to corner entry and exit is the ability of the rider to steer into and out of the corner. Such vehicle behavior is desirable in low performance riding, such as the kind referred to in the Wiki page (a reference notoriously bad for its errors and bad information, by the way), but isn't how one goes about developing a high performance bike on which one aspires to corner with any degree of speed.

 

[Lowell]

"Which is why I'm messing with recumbents. I'd rather develop what's next than consume what's yesterday. In the mean time, a lowracer recumbent is the fastest configuration for a low powered electric bike - arguing otherwise is just so much grumpy old man BS.

NOBODY is powersliding a 1000 watt bike at 100 mph and highsiding it anyway."

Agreed, it's a bit like saying a Smart car has bad high speed handling due to the short wheelbase and high CG. It just doesn't matter to 99.9% of Smart owners.

Except this guy:
http://www.leafstream.se/smart/index.html

 

[safe]

The higher the CG, the more the front tire has to steer to deviate the path of contact to attain the desired lean angle. Or it attains the desired lean angle later with the same steering angle. And at high speed, the limiting factor to corner entry and exit is the ability of the rider to steer into and out of the corner.

Obviously you know how to ride because the RZ was a wonderful bike and so I'm beginning to respect that you aren't just unaware of the physics and just "wishing" with your heart that recumbants are a better path. So let's keep this a respectful debate. (so far so good)

You probably remember that short period of time when they were experimenting with "under the bike" gas tanks. What they found (to their amazement) was that the lower center of mass made the bike harder to initiate into a rotation because the torque of the tires (the countersteer) was much lower when the distance is shorter. So people crashed and burned and "lesson learned" they stopped trying it.

The recumbant places so much of the mass so low that the torque to steer is going to be very low. The result is that it will be sluggish in turning and you will have less reaction time to deal with a slide. Being slightly distant from the tires allows the "arc of motion" of the slide to be smaller... so if you are rotating right near the tires you might rotate 10 degrees, but further away it might be only 5 degrees. The distance creates a more precise turning capability with more torque at all points.

So reaction time is AGAINST the recumbant.

There must be some type of physics that has not been communicated so far to explain how you reverse this pretty solid argument against the recumbant.

Let me add a thought here...

There is the "location" of the center of mass and then the "inertia" of the center of mass. The inertia is about how "spread out" the rotating object is. The location is about how high it is. The "ideal" seems to be to have the majority of the mass in a tight ball centered around the human body. If the mass is concentrated in the middle then less inertia is built up in a slide. (rotation about the leaning axis, not the turn based axis which a recumbant is no better at dealing with anyway)

A high side usually goes...

1. Tire breaks loose.

2. Bike begins to rotate outward in the rear, but stays on it's line in the front.

3. Rider countersteers. (usually too much)

4. Rear tire catches the road and transmits huge energies into the frame.

---> a. Frame acts like a spring and retains the energy.
---> b. Frame is rigid and forces the tire to break loose slightly relieving some pressure.

5. If the above was part 4a then the spring unwinds and you get a big thrust into the air and a crash. If the above was 4b then you have a decent chance of hanging on and recovering.

Question: Describe the "improved physics" that would make the recumbant go through the previously described circumstances...

 

[safe]

NOBODY is powersliding a 1000 watt bike at 100 mph and highsiding it anyway."

I've powerslided a "Gravity Bike" just by gravity alone when racing downhill. (at about 30 mph) Scary, yes, but any time you are trying to compete in any bike you will eventually get to the limits. Racing is about getting as close to the limit all the time. It's the "game" itself. So to "dismiss" going near the limit seems unrealistic... it definitely happens...

And let's not forget good old "sand on the road". That is a real part of life too and if you aren't prepared to get a little sideways and recover you will crash.

 

[Anonymous]

How a bike handles at its limit is very near and dear to my heart! But a G-bike can "drift", not powerslide. But yes, the behavior is much the same.

Just for your edification, it's spelled "recumbent" - there's no "a" in that word.

I understand the physics extremely well. I also remember Freddie Spencer's old triple 500 with the under-engine gas tank - I was wondering if anyone still remembered that. One of the big problems with that was simple: any time you make a big change without any other alterations will result in weird behavior. The rake, trail, swingarm angle, rider position, etc... are affected - and those things weren't changed. The rider was also used to a certain set-up, and changes can increase lap times when the rider can't handle them. It's a commonly known fact that your average rider can lap faster on an SV650 rather than a GSXR1000 - we both know why that is and both know which one really is faster.

As far as the reaction time to a slide, you're right - the lower the CG, the less time there is to react. That also means that the low CG vehicle responds faster to the rider's input, which is a good thing. What's the most forgiving for mistakes isn't the fastest - never has been and never will be. It is easier to learn to slide around on a MTB than a lowracer, just like it's easier to learn to fly in a Piper Cub than a P-51 Mustang. That doesn't make the Cub the performance airplane.

I'm sure you've heard the "balancing the long handled hammer vs. the short handled hammer" analogy. It is fairly accurate - when riding at low speeds in parking lots. But whan making a hard left/right transistion at the limit, it becomes more like trying to flop a long handled hammer that's lying on a table with your hand on the base of the handle vs. the short one. A bike with a low CG will place far less demands on the tire to roll the bike. Less demand = more traction available. More traction is both faster and safer. But we always find a way to get rid of that annoying excess traction by going even faster, don't we?

There's a reason GP bikes don't look like dirt bikes - if higher was better, then they would keep raising them. They don't. There's also a good reason why the stupid "stinkbug" bike setup that was all the rage 10+ years ago has gone away.

I really love this stuff - I'm, uh, shocked that there's anyone else in the e-bike world that finds this stuff amusing. One of my main attractions to electrics is that they give the chassis designer (aka ME) a lot more design freedom.

 

[safe]

Just to add a little to the center of mass "inertia" verses "location" thought... it's possible that the "location" of the center of mass is very low on the recumbant and so you gets some negatives on that, but the "inertia" might be pretty tight and so you get a positive on that.

So there might be contrasting advantages and disadvantages so the net effect might not be as bad as one might assume.

 

[safe]

I also remember Freddie Spencer's old triple 500 with the under-engine gas tank - I was wondering if anyone still remembered that.

Okay, so you "know your stuff" when it comes to bike history. 8)

Seems to me what you want for the street is whatever produces a very predictable slide. You actually want the tires to break loose pretty easily, but controllably. If the recumbEnt does that (sorry, I forgot they are called "bents") then it might be pretty good.

And it's true that a "powerslide" involves power, while a "drift" just involves momentum... but the idea is to be able to handle the breaking loose of the tires and recovery from that event.

 

[Anonymous]

Well, it sure sounds like you know both how to have fun on 2 wheels and how to make it happen.

That's my idea of fun as well!

 

[safe]

This project is interesting.

I think you missed a very valuable possibility on this in that you could have placed the legs within the protective cage and simply allowed the rider to pull them to the side when needed. (there's a tube in the way keeping the legs exposed as shown) If the legs were protected within a moncoque shell you could crash the shell and never have your skin touch the pavement. You could then strap the rider in very securely and be almost like an Indy Car on the inside. Ideally you might even make the feet drop down from above rather than sticking out the side. It's protection from the side in a crash that is important. (once you are up and running you don't need your legs for stability anymore)

The aerodynamics would be excellent!

I'm thinking that the "moment of inertia" is so low on these things that it's the best feature. Since it takes less to get the mass to rotate in the first place you have less to worry about in it getting away from you.

What feedback do you have on how it handled?

 

[Anonymous]

Let me add a thought here...

There is the "location" of the center of mass and then the "inertia" of the center of mass. The inertia is about how "spread out" the rotating object is. The location is about how high it is. The "ideal" seems to be to have the majority of the mass in a tight ball centered around the human body. If the mass is concentrated in the middle then less inertia is built up in a slide. (rotation about the leaning axis, not the turn based axis which a recumbant is no better at dealing with anyway)

A high side usually goes...

1. Tire breaks loose.

2. Bike begins to rotate outward in the rear, but stays on it's line in the front.

3. Rider countersteers. (usually too much)

4. Rear tire catches the road and transmits huge energies into the frame.

---> a. Frame acts like a spring and retains the energy.
---> b. Frame is rigid and forces the tire to break loose slightly relieving some pressure.

5. If the above was part 4a then the spring unwinds and you get a big thrust into the air and a crash. If the above was 4b then you have a decent chance of hanging on and recovering.

Question: Describe the "improved physics" that would make the recumbant go through the previously described circumstances...

Great analysis! As stated above, you are right - the recumbent rider would only get flicked off the bike at a different attitude - hardly a worthwhile thing to pursue.

But.....

I've had a lot of fun, um, I meant work studying crash videos. Virtually all the highsides started as a tiny slip and grip from the front tire. As the front tire slips, the front end tucks in a little - but it regains traction in a few revolutions or less (from sloughing off old rubber and exposing fresh rubber?) and grips. When it grips with the front tire turned in, the steering angle now both unweights the rear end and countersteers the bike upright. The combination of the 2 now more or less whips the bike up and around. Since the rider is still on the gas, the back end breaks loose and, well, continues on just as you described above. All of the above happens in fractions of a second - the rider is flicked off before he even knows what happened. The changes in tire profiles (as you described earlier) have helped make highsiding a lot less frequent (along with some other things!).

By having a lower pitching moment, the whole hobby horse effect is lessened a lot. That, at least in my experience and observation, is what the difference is. So in theory, one could get away with "highside prone" tires in a potentially safer platform and drop lap times.

PS

The one bad news of a low CG recumbent platform is that it is harder to get much weight transfer to the back tire while driving out of corners. Which means it is more likely to step out and lowside. I'm told the Gurney Alligator tends to step out pretty bad at the back - and that's what's holding its lap times up. There are ways to fix that.....

 

[Anonymous]

This project is interesting.

I think you missed a very valuable possibility on this in that you could have placed the legs within the protective cage and simply allowed the rider to pull them to the side when needed. (there's a tube in the way keeping the legs exposed as shown) If the legs were protected within a moncoque shell you could crash the shell and never have your skin touch the pavement. You could then strap the rider in very securely and be almost like an Indy Car on the inside. Ideally you might even make the feet drop down from above rather than sticking out the side. It's protection from the side in a crash that is important. (once you are up and running you don't need your legs for stability anymore)

The aerodynamics would be excellent!

I'm thinking that the "moment of inertia" is so low on these things that it's the best feature. Since it takes less to get the mass to rotate in the first place you have less to worry about in it getting away from you.

What feedback do you have on how it handled?

That was an experimental machine - never remotely intended to be reproduced as it is. I'll go through the flaws first!

The legs out the bottom/side was a mistake - you're right, they would be better out the top! The problem was putting my feet down and whacking my knees on the upper frame rails. That HURTS!!!

The steering control torque tube was waaay too flexible - it required a very steady hand to steer it. Once I got the hang of it, it was tolerable, but it still should be a lot stiffer. I never let anyone ride it - the fixes in the followup should take care of that. But it does roll in and out like nothing else - it feels weird at first, but the head gets used to it.

The seat is too upright, but I wanted to figure the steering out without having to deal with any learning curve my inner ear and different visual perspective might cause. The upright seat position helps there, but gets old fast.

The gas ones have been ridden by others - and all generated a lot of enthusiasm. One of the gas ones was taken to a scooter race about 1.5 years ago - and a lot of kids rode it and liked it a lot. But that race series ended - and so much for that. I've also done zero promotional work with them other than to expose them on the internet. In the mean time, the electrics have made some great strides in the last few years - I can build a much better light electric racer than a gas one for the same amount of work and money. No noise, no vibration, no smell, no problem!

The next one (I hope) won't look anything like the above picture. But here's what I'd love to do this spring:

Have the frame along the side of the rider.

Run a "bodysock" (stretchy full fairing) around the bike and rider for aerodynamics and maybe some added road rash protection. The fairing nose would still be plastic, but I'm wondering what the potential is for a kevlar/lycra/nylon fairing would be - it would be easy to get in and out of, easy (if not cheap) to replace, and easy to add graphics and such (hey, gotta have sponsors pay for my fun...)

Two wheel drive - easy to do with electrics. One thing low CG type bikes tend to do badly is transfer enough weight over the rear wheel while accelerating out of corners. Which is where 2WD comes in.....

It'll probably have normal handlebar type steering - the stick works great but takes a long time to adapt to.

Etc...... Gotta build something - I'd hate to see the next one not get past the "hot air" stage of the project! Most importantly, it would be great to get some feedback on it.

 

[safe]

The legs out the bottom/side was a mistake - you're right, they would be better out the top! The problem was putting my feet down and whacking my knees on the upper frame rails. That HURTS!!!

Well you need to have your legs to balance the machine at a stop, so they have to touch the ground somehow. I think climbing in from the top like an Indy Car is a good idea and all the crash protection the sides could give would make it a safer vehicle. Seems to me all you need is holes out the bottom so that you can touch the ground when needed. The entire bottom could be open except for the seat and some sort of foot rest while riding. That way you could steady the machine as you climbed in. (however, you would be better off with parallel kickstands sticking out each side for when you are loading and unloading yourself from the machine)

I would agree also that you need something like handlebars so that you can get the fine level of precision to control the wheels. You don't need much (I would guess) to steer such a thing so hyper-sensitivity would be a real problem.

What about a steering wheel that is geared way down so that you can bring your arms close together and get the same effect as handlebars? After all "either" control system is alien to begin with... you are inventing something that can be done any way you want... Maybe even have the steering wheel detachable like in the Indy Cars to make getting in and out easier?

 

[Anonymous]

I would agree also that you need something like handlebars so that you can get the fine level of precision to control the wheels. You don't need much (I would guess) to steer such a thing so hyper-sensitivity would be a real problem.

What about a steering wheel that is geared way down so that you can bring your arms close together and get the same effect as handlebars? After all "either" control system is alien to begin with... you are inventing something that can be done any way you want... Maybe even have the steering wheel detachable like in the Indy Cars to make getting in and out easier?

You've guessed right about the sensitivity.

That's the good side of remote steering - you can do it however you want. I'm doing the wide bars thing right now for familiarity, but I'll bet that, as a body of experience and consensus comes about, that'll change. The possibilities and potential seem great - to me, at least - I'm looking forwards to what comes of it.

 

[safe]

You are really being a pioneer on this. After a lot of experimentation you very well might discover that you have taken the motorcycle into a new reality, but it also might end up just hanging from the ceiling and talked about as a "grand experiment".

My online name is "safe" and that's how I'm planning to design my electric bikes... I'll use the most well established theories and assemble them together to create an "electric road racer". (I could have called myself "conservative", put then the login would take too long :wink: )

Once my idea is "done" (well) then I'll move on after that... but so far no one has "done" the "electric road racer" yet. Pockets bikes are "sort of" the same idea, but they are micro sized and don't handle well. I want a true "electric road racer" that handles like a 125cc road racer at speed, but weighs less than 100 lbs. (many of the handling nightmares on motorcycles have to do with so much weight)

 

[Anonymous]

After a lot of experimentation you very well might discover that you have taken the motorcycle into a new reality, but it also might end up just hanging from the ceiling and talked about as a "grand experiment".

It's already there.....

I just hope it has better developed company some day. Otherwise, it'll be just that - a conversation piece.

Your endeavors sound like a blast - I wish you a boatload of success with that! I agree with the weight part completely!

A lot more people might take up racing if the vehicle was a lot more "portable" and could be stored easily and cleanly in the house/apartment/condo. And there might be a lot more places to race without the noise. A light racer won't destroy pavement, either.

 

[safe]

The "Gravity Bike" is a good example where people can gain a great deal of entertainment by racing something that has no power other than gravity. If there were races with electric bikes the whole race would be like in NASCAR where drafting would be everything. People can only get streamlined so far and beyond that it's about how you slipstream your fellow riders.

"Gravity Bikes" are fun, but you need a separate car to drive you up a hill. With an "electric road racer" you could race (slowly) just about anywhere. And with gears even 1000 Watts can get you up to some nice speed... you just have to "work at it" (shifting) to get there...