E-Bike Racing: 2011 World Challenge

[NorCalTuna]

FWIW, the SCCA and many other sanctioning bodies describe weight specs, generally, "w/" driver, and they are minimums. I'm letting the worms out here a bit, but I think it's important to at least pay lip service to what has been done, historically. I agree with everything else that has been said about the rules, but dogman is right on. It's like having import drag without civics. It's like a BLT without bacon.

from an arbitrary section on shifter carts from the scca SOLO rulebook (which honestly applies as well as any other rule system here, track wise)

" Minimum weight for entrants in 125cc shifter karts is 385 lbs. as raced, including driver, regardless of driver gender or class en- tered. Weights for entrants with karts having other engines are as listed in section 19.1.D.3."

So, given a 165 lb. driver, the scca is thinking the cart should be 220 lb.

here's the whole solo book, for brain food.

http://www.scca.com/documents/Solo_Rules/2010_scca_solo_rules.pdf


honestly, a max weight contest could become dangerous and ludicrously expensive, while a min makes the sport accessible to far, far more people and setups. You want some people squeekin' by, and some people adding ballast- that way it's fair to the rider. Unfortunately, it's not really easy to safely add ballast to a bike, unless competitors know far ahead of time that they will have to.

The max weight rule is further problematic. I'll use myself as an example, at the risk of showing my hand : ^). I'm about 160 with gear and a helmet, but Nerdmobile ][ will be about 85-90 lbs- it's full sus bike, a specialized big hit fsr, an x5 and some lipo. Well, i'm SOL. NMB1 would be ok weight wise, and range and power wise, but it's not a particularly compelling tech display, and will be severely limited by it's lack of a suspension (but i'd still race it!). The rule, at 70 lbs, excludes pretty much everybody who you'd actually want to see race and pretty much every x5, which with a wheel and tire is half the weight allotment. And, by making suspension bikes basically inaccessible, the rule may even make the sport unsafe, or worse, lame. I think a good number of folks should actually weigh the bikes they have before we arbitrarily come up with that figure. Light riders like myself are naturally disinclined to this sort of rule when light vehicles are in question, which raises another reason to do a minimum: I'm sure that people who are better nourished would appreciate the lighter ones to concede a bit of the natural advantage, which is obviously part of the spirit of the SCCA rule. Honestly, I'm trying to argue for a better, more accessible and competitive event; picking a number from the hat, I say 260 lbs w/ rider min, which anybody remotely reading the last paragraph will know is entirely self serving, about my projected fighting weight, plus some ballast. 8) Hey, what can I say- this also would get the 190ish lb rider, closer to average, on that legendary 70lb bike, on the team, and make the 220 lb guy with an 80 lb rig only feel like he's at 40 lb disadvantage, rather than 90, which is me on the amazing 70 lb bike. I'm not saying it's impossible, but if your battery says "ping" or your motor says "x5" you're probably feeling the same burn right now. Even a 9C weighs 17.6 lb.

70 lbs is a very noble goal but somewhat difficult to obtain outside of very specific setups, and while it wouldn't be the first time rules write the successful equation, I'd argue that the endeavor seems to be sustainable, usable performance over absolute performance-however you bring that to the track; for that matter, accessibility and fairness over absolutes in general, which also is the ethos of AMA and SCCA racing, i'd say. Theres people who bring huge, huge dollars to those sports and you find them stuck in impound explaining away strange wires and hoses (or the aluminum "LEAD BARS" one guy had in his trans am I saw one day- how DID he think he'd get away with that?) as frequently as you find them on the podium. The really good guys are already at the BBQ.

 

[liveforphysics]

More of a formula 1 type race for ebikes,

F1 pushes the limits of current tech, so should this I suppose.

Yes, I think the biggest advantage of any type of racing is to create the need/demand for innovation in designs, which then trickle-down into non-racing builds.

I guess you could call it like an F1 event for e-bikes... but rather than an exclusive multi-hundred-million dollar budget being needed, in this event, no reason $1,200 in a bike can't make you a winner if you practice your riding skills and take the time to tune a setup to perform well and be reliable etc. I know some folks on here will gripe about the budget being out of reach etc etc, but really for something a year away, it only takes the sacrifice of the price of an espresso or a couple soda's a day to make a competitive entry.

 

[John in CR]

350lb minimum weight sounds like a winner to me. That'll separate the men from the boys, or maybe the boys need their own 250lb min class. 8)

 

[Tiberius]

Wow, page 6 in less than 48 hours.

Some of the suggestions about classes, weights, etc, seem to be aimed at making a handicap type of race - ie., where everyone is equal regardless of what they start with. Now, that has its place, but its not what we're trying to do here. This is a race, and it should be an out and out competition, where, as Luke says, entrants seek out any and every advantage (within the rules and with sportsmanship).

Someone mentioned the F1 of e-bike racing. I like that; its kind of what I had in mind. But we need a few basic rules to make it e-bikes instead of motorcycles, and to stop it turning into a competition between budgets and raw power. A weight limit, working pedals and the distance/time should achieve all that quite simply.

Please think about what you are trying to achieve if you propose extra or different rules. There is a law of unintended consequences and if you try, for instance, to make it more inclusive and help the back runners, quite often all you do is just hand the front runners another opportunity to get further ahead.

I'll give you an example. I chose a distance of 12.5 miles / 20 km because it will take 25 mins at 30 mph. We could expect the front runners to come in around 20 mins and the laggards around 30. It is of course possible to have a series of shorter races; I've seen many good races that last less than 10 mins.

But think what it means for batteries. As proposed, the front runners will be averaging 3 C discharge, so that could mean 10 to 15 C peak. If instead you have a series of short races, then the front runners will be running 40 or 50 C discharges and 10 C charges. Suddenly you are into specialist batteries and chargers and from the point of view of the typical e-bike, its got less inclusive instead of more. You would get fewer entrants and the difference between the front and the back runners would get larger.

Nick

 

[liveforphysics]

Theres people who bring huge, huge dollars to those sports and you find them stuck in impound explaining away strange wires and hoses (or the aluminum "LEAD BARS" one guy had in his trans am I saw one day- how DID he think he'd get away with that?) as frequently as you find them on the podium. The really good guys are already at the BBQ.

When I ran in a BOTI class that required 2150lbs minimum vehicle weight (with driver), I bolted a row of 25lbs lead-ingots behind my front bumper-bar under the bumper cover on the front of my civic. After back to back exploded axles in quals, we had to jump the tire pressure up 3psi to keep the car from hooking so hard! lol! Sadly... later in that event I broke a handful of teeth off one of my spider gears and couldn't find/buy a spare LSD type spider gear set from anyone at the track. But now we're way off topic. lol

 

[liveforphysics]

Also, for the guys fussing about the weight of an 530x series motor being too heavy to make a competitive bike, I'm planning on using a 24.8lbs BRUSHED motor for this event, and it's not a hub motor, so I've also gotta build a drive system around it as well, rather than just bolting into dropouts. If I'm not mistaken, your 530x series motors are something like 23.5lbs all laced up into a rim, which makes a reliable and read-to-go traction drive system?


I should add that I'm going to try my hardest to shave about 5lbs off that 24.8lbs POS motor though. And I'm going to make it a stressed member of the frame to minimize frame weight.

 

[liveforphysics]

I'm also thinking to prove the "working pedals" aspect of the bike, it must be sucessfully ridden up the driveway at my parents house (or something similar) with the battery disconnected, and not having your feet touch the ground. It's about 120yds of a very mild 1-2% slope. I think if you're bike can do this, then it counts as having functional pedals, even if they look something like this.

Also, for the guys who like drag racing, the field there is wide enough to do about 20-30 bike/rider wide drag races. We've done some 10-wide dirtbike sprint drag races there, and it's such a hoot to watch with bikes flipping over backwards on the line, or fishtailing giant rooster tails into wrecks, or not being able to stop before they hit the house etc etc.

 

[NorCalTuna]

I think the vigor of the thread indicates the pent up demand for this, for motorsports to move beyond ic. Sorry for the earlier HUGE post (I write, therefore I type)

great broken parts story, luke- funny when an idea works too well, huh? On the road race VWs, we always noticed the car exited worse the lighter the bumper was- it was years later at russell, after a lecture from carroll smith, that I realized the weight forward of the axle actually helped the car accelerate out of the corner... We all put our HUGE us spec bumpers back on and crash damage got cheaper to boot.

I'm not proposing making an equal race; thats impossible. I'm implying that the rules are stated contrary to ANY KNOWN tradition, including F1, which has minimum weights very, very rigorously enforced. (for that matter, I've never seen an F1 car without a suspension...) F1 isn't completely open, by any means at all, so if an open race is what is in favor, F1 isn't an appropriate term. Here's a brief of the weight rules.

http://www.formula1.com/inside_f1/rules_and_regulations/sporting_regulations/8688/

It would be hard for any combination of two of these elements to be on your bike and not be too heavy:

Large Motor- the limitation for power is no longer batteries or controllers but motors, which are currently massive to handle the temps.
Suspension- my daily driver, at about 3k watts, is about as much as a no-sus bike can safely handle... this is a race, right? With speed?
Lifepo4- saying the second best, sort of, technology doesn't make the show is silly. I can understand no SLA, thats unsafe.

It's hard to say any of those don't belong here- possibly lifepo, but I think the case can be made. Is there a divide between what Nick and I generally construe a ebike to be, causing this friction? To me, the motor is the prime mover to move fast, I am the secondary thing that pedals under 18, and twists the right handle up to 40 or so. This takes a fairly heavy motor, and speeds like this make suspensions attractive for safety's and handling sake. It's not a motorcycle, I pedal routinely, but my demands for speed (isn't this a MOTOR SPORTS event?) and handling dictate a somewhat more sophisticated, powerful machine than perhaps others have in mind. That said, I'm not sure- as has been pointed out- how uncommon 3-9k watt (or far more as the new 150v, 24 fet controllers are coming out) bikes already are and will be a year from now. Just sayin.

 

[drewjet]

This sounds great. I really like the idea.

For events to tie in to, have a look at Electrathons. For those that don't know it is a 1 hour race on a closed course, battery limited race. It has a 2 hour break between heats. I think E-Bike racing would be a great tie in.

We have 7 races planned for the next season here in Central Florida, I think I could easily talk the organizers into adding E-Bike racing to the card.

I like the keep it simple rules.

Let's go racing boys.

 

[liveforphysics]

With all the suspension talk, I would just like to add that a kart track runs karts with no suspension sitting 1/2" off the ground over it at 80-100mph. That's how smooth the kart tracks are here. I'm thinking scooter tires on a BMX will likely be about ideal.

This hill climb event would be normal good condition pavement smooth, and let me assure you that it gets steep enough you won't worry about reaching dangerous speeds to be running no suspension.


A minimum weight works in karting because everyone has the same displacement engine, and carries roughly the same quanity and type of fuel, etc etc. This means by making a uniform weight, everybody has a similar power to weight ratio, so the racing stays tightly grouped together, keeping it exciting for spectators, and making it more about driver than vehicle and techno innovations.


What happens with a minimum weight restriction in E-bike racing? I'm 6'2" and 215lbs right now (need to diet!). If NorCalTuna is 160lbs, then his bike will have 55lbs more motor/battery/controller/tires/brakes than my bike... If we were all specified that we were only allowed to use an unmodded 9C hubmotor, an unmodded 50amp 50v controller, and a ping 48v 20Ah pack, then yes, having a total vehicle weight minimum would make sense.

In an open type format, it would be utterly absurd though. I would have to get the 105lbs ex-BMX champ security guy here at work to by my rider by proxie, and then he would be able to ride a full blown electric super-motard motorcycle build with pedals strapped to the front wheel...


If the bikes are all fixed at 70lbs maximum, then the very large weight differences between riders are just a straight 1:1 penalty for the big heavy riders (like myself) and a straight 1:1 advantage for the lightweight guys. If you set a bike+rider weight minimum, then you make the weight penalty difference between riders no longer a straight 1:1 advantage, but you've multiplied it into a 2:1 leveraged advantage, because each pound lighter they weigh is a pound they can put into the bikes powertrain system that a heavier rider can not apply to his powertrain.

In other words, you create a greater performance gap in an attempt to level the playing field to be more fair.

 

[Tiberius]

It would be hard for any combination of two of these elements to be on your bike and not be too heavy:

Large Motor- the limitation for power is no longer batteries or controllers but motors, which are currently massive to handle the temps.
Suspension- my daily driver, at about 3k watts, is about as much as a no-sus bike can safely handle... this is a race, right? With speed?
Lifepo4- saying the second best, sort of, technology doesn't make the show is silly. I can understand no SLA, thats unsafe.

It's hard to say any of those don't belong here- possibly lifepo, but I think the case can be made. Is there a divide between what Nick and I generally construe a ebike to be, causing this friction? To me, the motor is the prime mover to move fast, I am the secondary thing that pedals under 18, and twists the right handle up to 40 or so. This takes a fairly heavy motor, and speeds like this make suspensions attractive for safety's and handling sake. It's not a motorcycle, I pedal routinely, but my demands for speed (isn't this a MOTOR SPORTS event?) and handling dictate a somewhat more sophisticated, powerful machine than perhaps others have in mind. That said, I'm not sure- as has been pointed out- how uncommon 3-9k watt (or far more as the new 150v, 24 fet controllers are coming out) bikes already are and will be a year from now. Just sayin.

Hi NorthCalTuna,

I wonder if you have answered the question when you talk about "any combination of two". If its a balance between these various factors, its not obviously dominated by any one of them, and some engineering calculations and trade-offs have to be done, then I think its just right.

The 70 lbs / 32 kg proposal is chosen to be a round number (we'd have to decide on whether it was 70 lbs or 32 kg because they are not exactly equal), but it wasn't plucked out of the air.

There is, or was, the idea in UK and European legislation that 40 kg is the dividing line between a bike and a motorcycle. 40 kg is too high and I wanted to come down from that. I weighed a few bikes and e-bikes and I'm confident that a seriously competitive e-bike can be built for this distance below 30 kg. In fact 40 kg is what I measured a set of bikes at when they were all loaded up with extra batteries for an endurance event.

You mentioned LiFePO; the red bike in my avatar is carrying enough LiFePO to do twice the proposed distance. It is a bit heavier than the same Whr in LiPo but not enough to dominate the equation.

Nick

 

[liveforphysics]

I would just like to add a bit about the proposed technical challenges with motor heat, battery size, controller heating etc etc.

It SHOULD be difficult!!! You SHOULD have challenges in motor heat/cooling. You SHOULD have strict compromises to make between controller power limits and battery capacity. You SHOULD need to struggle and scratch your head and crunch numbers and run tests in parking lots on power usage etc etc.


It's a race for God's sake! The whole idea is to make a challenge that is difficult and involves making tough decisions to find the best compromises!

Parts SHOULD burn-up. This is why we gotta do the hill-climb last... because I think there will be a lot of magic smoke getting released during the hill climb stage...


*** Edit - I've got like 150x IRF4110's sitting here at home, and plenty of electronics repair equipment, and I will freely give IRF4410's to anyone who blows a controller during the event, and I'm sure there will be enough skilled folks on-hand at anytime to do the FET replacments***

 

[dogman dan]

It seems like the intent of the weight limit is to limit batteries and motor sizes. So maybe do that with other rules instead of making it a contest to see who can build the lightest bike, so as to carry the biggest battery?

Like I said, once you start setting limitations of any kind, all kinds of difficult questions pop up, somebody gets excluded that maybe should be in, etc. Look how hard it's been to write good laws against driving and talking on cell phones as an example of the difficulty of rule making.

But with the smart people on this fourm, I'm sure something can be figured out to make a race that's fun, challenging, not ridiculous expensive like an unlimited class, still difficult to make a bike within the rules that will podium, yet still allow the typical 72v x5 setup.

I still like the idea of a battery limit. 20s lipo voltage max, 10 ah max rated size or whatever seems the right numbers. The hot competitors will all have turnigy or equivilant, but guys with headways could fit in the category, or even two 36v pings. Do some testing so that race length matches the battery size at 50 amps, but you'd run out at 100.
Then a guy could use strategy, unleashing his 100 amps in the final sprint, or screw up and slow way down at the end as voltage sags.



Testing each bike for wattage like Safe wants to do eventually, or installing amp limiters, is too much pita. But we all would know just by looking at it if somebody was packing 15 ah instead of 10. If somebody squeaks 11 ah in, hey, thats racinge eh?

I really do see where the low weight limits intent is, but the reality is that it will eventually have guys racing on too light frames to pack in more motor and battery. There goes low cost, and there goes some safety. It might be better at least in the beginning, to let people run as heavy and strong a frame as they like, and let the mass slowing them down after a corner be the penalty for it.

I dunno, you want a nice simple three sentence rulebook, but a weight limit that is too low excludes, and one that is too high defeats the purpose of it entirely. It's pandoras box. But if the primary purpose of the rule is to exclude huge motors and batteries, then just specify battery size, and exclude specific motors. Somebody will show up with something huge that is not specifically excluded of course, so somebody has to be able to judge a bike on the spot, and include it, or not. Too big a motor or controller will still penalize a rider if the race length and battery size are matched well enough.

 

[liveforphysics]

I dunno, you want a nice simple three sentence rulebook, but a weight limit that is too low excludes, and one that is too high defeats the purpose of it entirely. It's pandoras box. But if the primary purpose of the rule is to exclude huge motors and batteries, then just specify battery size, and exclude specific motors. Somebody will show up with something huge that is not specifically excluded of course, so somebody has to be able to judge a bike on the spot, and include it, or not. Too big a motor or controller will still penalize a rider if the race length and battery size are matched well enough.

Doesn't the bike weight cap do this all perfectly though? If you want a huge heavy motor, you're going to have to skimp on battery weight. If you want a giant battery, you're going to need some light motors. Want big 5lbs motorcycle tires for awesome handling? Then it means less weight for battery and motor, etc etc.

It finds it's own balance naturally by the entire package needing to be 70lbs.

For the folks who think it takes exotic everything to make 70lbs, keep in mind, Tiberius dominated (as in destroyed every class they had by a huge margin) his e-bike contest in the UK. He is obviously confident he will win this one as well. What did he dominate with? A small hubmotor and a some low-power LiFePO4 pack (ping or something) on his handle bars.

I think his plan here is to come out with something like a 9C and a ping pack or two bolted to a road-bike, and win by out-handling all of us (like I think he did in the last e-bike contest). If it goes anything like an amatuer motorcycle race, an extremely skilled rider can go out on the track with a 25hp Ninja 250 and absolutely slaughter the whole field of amatures riding 150-200hp +1000cc superbikes.

Only the hill-climb will really be a matter for max power and power stability to dominate, and the hill climb I've got in mind may burn up every super high-power bike that tries it, and it will get won by somebody pedaling up a 9C with a 25amp assist.

 

[Thud]

So its an event then?
Seems like a lot of discusion over something in its planning stage. I feel it is far more important to acctually just get an event together & get some exposer before imposing a book or rules on the 1st running of an event.

This is a new application of the technoligy & there are going to be wide ranging views as to what a real test of e-bike performance is. Just as in all forms of motorsport, A Motorcycle drag bike has little incommon with road racer & a poker run has nothing ot do with short track ovals.

My point is it just needs to start before it can be refined. (this conversation is de'javue of one with Safe at motored bikes LOL) I don't have the resources to aquire my dream version of the bike(or bikes) I would love to bring to the 1st "Olympia de' Electric Bicycle" but be sure I will be in 100% support of whatever comes up. Being one of the group at the weight diadvantage I just accept it as fact & set up acordingly. I haven't been below 200#s since 2003 at nearly 6'.

Luke, if your serious about taking the time to get this organized & running count me IN. I am in 100% support of whatever it looks like starting up. If its at all viable as a sport it will grow & evolve form there.

I see dogman has posted, all good food for thought. if you want to limit the amount of money spent on the bikes, just add a "Claiming" provision. where the Winners bike can be bought for a set amount of cash after the event. counter claims can be made & the winner of a bike is determinrd by a random draw. There is a guy from texas who bought a very fancy honda "works" bike one day the factories forgot to bring thier claming cash to the race.

 

[Miles]

A simple weight limit seems a reasonable way to start this off.

The other limit that might still be worth considering is an energy one (battery pack standardisation/weight seems too complicated, though) - the organisers supply a meter with a cut-off, to give a fixed dose. Probably need to factor in the rider weight, though...

 

[liveforphysics]

I think Thud has the right answer here.

A claimer race.

Anyone can buy any bike after the race for a fixed amount of cash that is deemed reasonable before the race. I sorts the low budgets and high budgets and levels things pretty nicely in motorsports.

This means if you've got the budget for a $5,000 custom carbon fiber frame and exotic wheels with Matt's new exotic 14kw motors and an $900 kelly, and a $1,500 of LiPo, you can get bought by anyone after the race for some reasonable amount, like $<2,000usd.

I think $2,000usd for a claimer would do it's job of regulating the budget differences pretty well right? I can't imagine you could find any normal non-electric bicycle road-race where the bikes were under $2,000usd...

 

[Tiberius]

So its an event then?
Seems like a lot of discusion over something in its planning stage. I feel it is far more important to acctually just get an event together & get some exposer before imposing a book or rules on the 1st running of an event.

Hi Thud,

That is a point. But I'm expecting to travel a long way and do some preparation, and I hope I'm not alone. People like me need to know what the rulebook is a long time in advance, so we can work out how to beat it. We'll be mightily pissed off if we put all the work in and then someone says "just run what you brung" or if we turn up and find we're excluded because of some late rule.

.....if you want to limit the amount of money spent on the bikes, just add a "Claiming" provision. where the Winners bike can be bought for a set amount of cash after the event. counter claims can be made & the winner of a bike is determinrd by a random draw. There is a guy from texas who bought a very fancy honda "works" bike one day the factories forgot to bring thier claming cash to the race.

I mentioned this before as a neat way of limiting budgets. I also plan to only arrange one way shipping for my bike and offer it for auction for charity after the event. That could be wrapped up in the claimer scheme.

Nick

 

[liveforphysics]

I want to formally say that I will give my entry, complete with batteries, away freely to anyone who can defeat me in the hill-climb event. Not a joke, dead serious about this. So if you want what ever bad ass bike I come up with, you've just gotta beat me in the hill climb and it's yours to take.


Also, NorCalTuna (who is a buddy in California and member here) mentioned the potential of renting a box-van to drive up all the folks bikes in California that need bike-transportation to Tacoma/Seattle and back. He also said he would help with the food. He is a very nice guy!

 

[dozentrio]

I want to formally say that I will give my entry, complete with batteries, away freely to anyone who can defeat me in the hill-climb event. Not a joke, dead serious about this. So if you want what ever bad ass bike I come up with, you've just gotta beat me in the hill climb and it's yours to take.

That's such a tempting challenge But what if more than one person beats you? I'm tempted to design purely for this

Honestly, I'm excited as hell for this event, regardless of the final form it eventually takes.

What Thud says about actually needing an event, before we start settling the rules, makes a lot of sense. However, with all the enthusiasm I am fairly confident that we'll have something set up by next year. I think a hill climbing race/event is a pretty good test of overall propulsion system performance. In fact, it's great! It punishes heavy bikes, and rewards efficient power transfer. Your bike might be able to do ridiculous bursts of power on a level, and that will serve you well on a kart track. But a sustained pull up a hill where your air-cooling is going to be limited by the slower speed is going to truly test the controller and motor.

However, this still leaves out an important aspect of ebikes. Reliability under duress. I propose an off-road event. Or re-propose... I think someone mentioned it on the first few pages. Something like this will truly punish all aspects of the bike. And before anyone says that it'll give an unfair advantage to full suspension bikes.. don't There are plenty of hard-tail mountain bikes, and many racers prefer them. And anyway, a full-suspension frame can be one of the trade-offs that we have to consider when designing the bike. It may help reduce the stress and vibration on the frame (and rider), but it'll eat up some of the budget.

Speaking of budget, I think a purely budget limited race might be the best idea. It leaves you free to design and innovate with cost being your only limitation. I think that this is where a whole lot of creativity is born. When you compare cold war technology from Soviet Russia to the US, I bet you'd see the soviet stuff is a lot more creative. I have no idea actually, but I hope the idea I'm trying to get across is clear. So perhaps a limit of $2000 is a good idea. If people want to spend half of that on a Plettenberg Predator, that's their decision. Probably not a wise idea though

 

[dogman dan]

I just think it would be sad to have guys with really nice FS bikes running a 530x and 72v battery going, oh well, sounds fun but my $2000 or more ebike is all I have the budget for, and I'm excluded from this race.

Hey, lets have a race and exclude a large portion of the fastest ebikes in the continent. Works for me, I run rc motors. That's basicly what the x5 owners are hearing here.

Guess the x5 frockmotor fans will just have to organize their own race. If they want one, they willl organize one. I just think the dividing line between motorcycle and bicycle is a bit heavier than 70 pounds, just like I think a 1500 watt limited race is more practical than a 1000 watt one.

The race bike I'm working on now should pass the 70 pound limit, but only barely. The main thing is to decide exactly what the purpose and intent of the limit is, and then write rules to reflect that purpose.

Personally I think you will sooner or later have a guy riding along at 40 mph when his frame folds with a 70 pound weight limit. Limiting the battery size makes more sense to me. Let people ride as heavy a frame as they want.

 

[GrayKard]

I don't think a cost limit is viable. First you have people who can get items at cost as they are dealers. Second you have folks who get freebies or discounts for testing. Last you have one time deals where great stuff goes for a steal. All of that adds up to a pretty big advantage IMO.

I really like the minimum rules idea even if that does exclude some. The weight limit and a safety inspection being the bare essential.

I also agree that the rules need to be set as soon as possible. If you are going to slowly piece a bike together over a year you need to know what you are shooting for. Waiting for the ideal motor, controller, battery, and frame to each be on sale if you are on a very tight budget.

Great thread, keep it coming!

Gary

 

[dozentrio]

I don't think a cost limit is viable. First you have people who can get items at cost as they are dealers. Second you have folks who get freebies or discounts for testing. Last you have one time deals where great stuff goes for a steal. All of that adds up to a pretty big advantage IMO.

Good points, but if we make the rule a limit of market cost, that solves both issues. Regardless of whether you had the components lying around already, go them free, or at a discount, you have to VALUE them at what it would cost someone else to get them.

I say let people ride whatever they want, so long as the combined $$ sum is no more than a certain limit. That should make it accessible to everyone who can afford whatever the limit is. Personally, I can't afford to build another $2000 ebike. The only reason I can afford to build one at all is that I have a suitable frame and the batteries already.

As people have said, if we set weight limits then we are essentially punishing bigger people. If you're 6'3 and like to work out, as well as race ebikes, you're out of luck! I think weight comes with its own natural penalty as it is. Acceleration takes more time, and takes more power. We don't need to set a weight limit in addition to this.

If we want to limit the amount of power the bike can draw, we could do stall tests on the bikes. Or install some kind of current limiting device at the battery. But this would turn the race into a choice of gearing, and how efficient your drivetrain runs.

So, to summarize, I suggest purely limiting the cost of the bike. That should result in sufficient design challenge, and make it accessible to everyone. What a reasonable limit for cost would be is another matter. I put $2000 simply as an example. Perhaps, when we look at the cost of components, it'll turn out that $2000 limits you to a cheap brushed 36V controller and a piddling few Wh of battery. What the cost limit would be set at will be a tradeoff between how fancy we want these bikes to be, and how many people will be able to afford to compete

 

[GrayKard]

Good points, but if we make the rule a limit of market cost, that solves both issues. Regardless of whether you had the components lying around already, go them free, or at a discount, you have to VALUE them at what it would cost someone else to get them.

That might work except for all the fabrication skills on this board. Who gets to determine market value on modified or one off custom frames? Custom torque arms? Custom motor mount plates? Some can even make motors and controllers from scratch...

Gary

 

[dozentrio]

Good points, but if we make the rule a limit of market cost, that solves both issues. Regardless of whether you had the components lying around already, go them free, or at a discount, you have to VALUE them at what it would cost someone else to get them.

That might work except for all the fabrication skills on this board. Who gets to determine market value on modified or one off custom frames? Custom torque arms? Custom motor mount plates? Some can even make motors and controllers from scratch...

Gary

Hmm.... that is a matter of skill, and innovation. We don't want to punish that. So, if for example someone can build a controller that can supply 300 amps and 150 volts at 8000 rpm because they're just that awesome, then this is a good thing. Because it leaves us with a controller design (we hope they're willing to share at a fair price). I would even go so far as to say that components which are hand built contribute 0$ to the value of the bike. That way, we are encouraging new and perhaps better designs. Am I on the right track here? Is there any downside to using a spending limit?