Rules For Racing...

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liveforphysics

New Member
Apr 19, 2011
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Santa Cruz CA
This is kind of how things are now, you can't buy real race ebikes today because the sport of ebike racing doesn't exist yet.
Not for you obviously, but I seem to have experienced about 12 ebike race events in the last couple years, from hill-climbs to full road-race courses to drag strips to kart tracks.

Come to this event and tell the regular group of powered bicycles racing together that the activity they are currently participating in doesn't exist.
 

Mike B

New Member
Mar 23, 2011
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I don't know why you think that a motor running at twice the speed will have the same heat as a motor running at speed with the same load.

Eddy current and hysterisis losses increase with speed and result in increased motor temperature.

In addition, all of the other loads; tire resistance, bearing losses and aerodynamic losses all increase too. As your chart shows, the wind loss increases rapidly, so your 2X motor is going to be producing more torque to make that speed and that requires more current which will make the motor really hot. 2x the current is 4x the heat.

If you take a motor that is making rated power at a certain voltage and a certain speed and then you double the source voltage and the load that motor is going to get real hot and then burn unless you employ additional cooling.
 

bairdco

a guy who makes cool bikes
Aug 18, 2009
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living the dream in southern california
safety, i think you're going to have to start your own racing organization.

there's a place down the street that sells those crappy production ebikes, and i see a lot of old out of shape men and women riding around on them.

you could post up flyers and have a lemonade stand, and maybe make some money selling those big sun hats with green visors to the geriatric race fans.

i'm only half-kidding.

watching nascar is bad enough. to watch it in slow motion on a "production" ebike is just ridiculous.

do you know anyone who would buy one? let alone 20 people so you could have a race class? or 50 people so you could break even on track rental?

the only people i've ever met who have any interest in a slow ebike are all over 60, and probably couldn't get around a kart track unless it had 3 wheels and first prize was a meatloaf recipe.

i used to race SCCA with a gutted, primered, insanely modified 75 honda civic hatchback that topped out at 150, and out-cornered every production car on the market at the time. even the so-called "supercars."

there's no way i could go back to a stock civic with a 0-60 time of 10.5 seconds and have a good time racing it.

luke's right. we go to races to race. we build bikes to compete with other people who are racing, not to compete with the girl on a pink ebike with a cute little doggy in the basket.

you said yourself that building your race bike was something you wouldn't wish on others. but, we are the "others." i've got a coupla grand in china paperweights because of this "sport" that you say doesn't exist.

i've got broken frames, busted knuckles, flashburned eyes, and skin i left at willow springs.

and i'm not the only one.

you're building one race bike that's never seen a track, and i've broken, torn down, and rebuilt at least 5 bikes in 2 years and 7 or 8 races.

again, i'm not the only one.

i taught myself how to weld, learned expansion chamber dynamics, gear ratio equations, fuel calculations, weight to power figures, and how to host a race for my friends and still pay my rent and have money to eat (and drink. and smoke.)

i just don't understand what kind of sterile utopia you're dreaming about, but it sounds to me like instead of a kart track, you'd be happier racing through a mobile home park, trying to outrun a golf cart.

despite my long winded, insulting tirade, i still encourage you to show up, get on the track, and find the enjoyment, the competitive spirit, and the friendships the rest of us have found on our stupid overpowered bicycles...
 
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liveforphysics

New Member
Apr 19, 2011
85
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Santa Cruz CA
Not true.

It's physics... electric motor heat is the current squared times the resistance. It doesn't matter how much voltage is involved as long as the current is held constant.
Holy chit Safe. It's been years of spreading your BS now, and you still don't have a flipping clue how a motor works.

Motors heating is its inefficiency, it's made of the sum of the copper loss and core loss. I^2*r is the copper loss, and the rest is core loss. Many functions of coreloss increase at the square of RPM, some at the cube, and some linearly.

Anytime core loss is greater than copper loss, adding current increases efficiency, or reducing RPM increases efficiency.


This is why we banned you from ES because you were un-teachable and continued spewing radically incorrect bullsh*t daily that some poor newbs actually were suckered into believing.
 

Goat Herder

Gutter Rider
Apr 28, 2008
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I think they should make a class just for Safety to race in, but gosh he will be looking at every one else going faster ''very happy about it too'' and saying they are all wrong? Or did that already happen?dnut

Everybody needs to slow down now lol.ride3

What I don't get is Safety does not have to race with any big dogs. His misleading post are misleading . Forever now I have read that he wanted to race all these faster bikes . It has been worded by him like we all had no choice. A bunch of hooey I say. They have different race classes for a reason.


Why is he trying to slow folks down that he does not even have to race with to begin with? There is already a slower class he can join. So in a nut shell he should just race those folks where he can fit in but he may just be to slow then? I don't think anybody wants to detune their H.T. motor from right out of the box as it came from the factory just for him lollaff

How slow can you go???
 
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Mike B

New Member
Mar 23, 2011
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Central CA
Go ahead and believe that eddy currents and hysterisis do not exist if you want, but I can tell you that they do.

Go ahead and measure the no load current on a motor at one voltage and then double it and see what happens to the current. There is no load on the motor, so where is the extra torque coming from?

With load the effect is even greater, you are pumping more current which creates more magnetism and makes these losses even higher.

Yes, basic physics.
 

Mike B

New Member
Mar 23, 2011
2,256
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Central CA
Works for me.

The heat is insideous too. As the temp increases, the r part of i squared r increases further increasing the loss.

The i part is the worst though.

I really don't see your idea of having say a 1 KW street legal motor and then turning it into a 2 KW race motor by doubling the voltage therefor increasing your speed (and the load) and thinking the motor will not get any hotter.

It just doesn't make sense.
 

Easy Rider

Santa Cruz Scooter Works
Jan 15, 2008
2,145
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Nor*Cal
I'm not by no means an expert on electric motors but I do work with a lot of 208v or 480v 3ph and single phase motors and the primary cause for heat has always been the amount of load put on the motor. I'm not bashing anyone but that's been my experience with heat. I'm just a student trying to learn.
 

bairdco

a guy who makes cool bikes
Aug 18, 2009
6,537
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living the dream in southern california
there's been a handful of custom ebikes at the races. and 2 handfuls of full built gas motors.

there's a bushel of chinese 2 strokers.

we're not a cult. we're guys that race. we may talk a lot of BS to each other, but we get along. on and off the track.

all you have to do is show up. decide for yourself. constantly pointing out why your theories are better means nothing if unproven at the track.

you can have the coldest running, longest lasting motor in the world, but no one cares if you come in last place, or don't race at all.
 

Goat Herder

Gutter Rider
Apr 28, 2008
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AHRRR!!! show up or shut up please. he's driving me crazy!
They will be racing with out him showing up for a Great Great many years to come and everybody will get along perfectly fine... just fine with out him! I know well enough none of this stuff is that complicated and all of the races promoters have worked well with the community just fine with out the weird cult ideas Safety has .

First step is to simply get along. Nobody want's to join Safety's race cult lol.:p
 

Goat Herder

Gutter Rider
Apr 28, 2008
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Increased rpm does heat the motor, but not by dramatic levels. Current is the dominant issue with electric motors.

All I'm saying is that if the sport is going to gain mass appeal then the rules should "encourage" people to run stock motors and just run them to higher rpms. The manufacturers of the stock ebikes would get wise to the rules and "detune" them so that when you bought the bike it was running at, say, 1800 rpm maximum. On race day you convert to higher voltage and run it up to 3600 rpm... no big deal.

I've actually tried some of this stuff on previous ebikes and it all checks out as true. Just don't exceed the current carrying capacity of the motor and it works fine.
They already do that. They have done absolutely everything with electric motors. Yes at the races that have been in progress for some time now! Where have you been?

I can prolly find links for you all the way from Endless Sphere lol. That is nothing new.....at all


The races are where they get to prove it !!
 

Goat Herder

Gutter Rider
Apr 28, 2008
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I cannot think of any bike with stock parts on it that I would ever want or have ever done for myself . They simply don't exist..... and very likely for me never ever will to my grave. For me it has to work...The most important thing... pretty don't cut the mustered with my every day use. It could be great looking and not even run lol. I just painted one of my cars so it would be worth more money it needed mechanic work which would have been way more practical but the paint job got more cash for it. Go figure? It will be nice just finish http://youtu.be/zbPvF7LqUjo it;)drn2

http://youtu.be/zbPvF7LqUjo
 
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Goat Herder

Gutter Rider
Apr 28, 2008
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The "better" racebikes would use fiberglass, but the entry level would probably be injection molded plastic. I know you're joking, but motorcycles come with a lot of plastic for fairings and other parts, so you would probably see a lot of entries on the cheap stuff.

My point of course is that the rules should "encourage" the use of stock bikes (modified slightly) and that makes whoever is building the bikes have an incentive to build better and better racebikes. Like the competition between Honda, Yamaha, Ducati, Aprilia, you would get different bike brands competing to sell into the market. Pretty soon the racebike market is flooded with good products that range from excellent to Walmart junk.
You do know that they currantly have race classes for different engines right? That is all they need and is clearly stated.. It has been working great!! This is Motor bicycle Racing. Ya forgot that all over again now too..
The right rules will cause this to happen. I'm just saying... :)
Wow you have been so far out of the loop? Folks have been making their own bikes for years now. This has hit so main stream there flat out is no stopping it no matter what happens!! Ever !! Since The Wright Brothers. It has not died out yet. Not gonna happen..
Right now everything is custom built and that's going to keep it as a small sport with limited appeal.
We just need a foreign manufacturer to make us some soon to be obsolete junk. Just look at the Baja line. I worked on those. I will build my own thanks..
Gotta get rid of this "mountain bike with motor" look in favor of something stylish and aerodynamic. The sport needs to look modern and aerodynamic to catch the general publics interest. (vintage is fine, but it's limited in public acceptance)
Say's you I know you have not looked at the sport currently now?? It is clearly speaking up for it self and has all kinds of great design.... Not just a mountain bike.
Besides that history has taught us that history repeats it self with design..
Or you can just continue with the vintage look and stay with a more cult like feel. (what do I know)
All right a Wallmart mess of fragile plastic malfunction!! That only goes 20 mph if that? for mebbe a block before some plastic falls off. Is this the training wheel Cult??laff


This sport will be "big time" when you can go to Walmart and buy a (plastic) full fairing ebike with a motor that runs fine at 20 mph, but can go fast when the voltage gets boosted.

Oh... one of these days I hope... (as I dream of a better future)

For now I just go one day at a time and try to finish what I started. :)
Yes Wallmart that should be every young child's first words. :rolleyes:
 

Thud

New Member
May 26, 2010
205
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West Michigan
How did all this recent crap end up in this post...I got a new rule to add: no more Thomas Edison chit please...
That made me laugh!
There aint no brake man on this train......& we is off track proper.

And this is just wrong:
Safety said:
A simple thought experiment:

Spin a motor up to it's "no load" speed. This will produce the MAXIMUM core losses based purely on the high rate of the poles swapping back and forth.

What do you get?

Basically no heat at all.
That is msinformation...I know from real world testing my 3" outrunners have an rpm limit based on Iron loss & induction heating. They hit a wall at 9k rpm's & any more needs to be activly cooled to keep heat in check....& no amount of air cooling will do it. they truly are only a 3kw motor with higher peaks but continuously...they are just motors
sorry for the off rail railings.....what was the topic again?
.duh.