Local e-bike racetracks

[Whiplash]

True enough, these days an x5 is no longer even close to cutting edge. Or any hubbie for that matter. The only real advantage of watt limiting as opposed to weight limiting would be not discouraging anybody from entering. It could be all about getting as many guys as possible to pay an entry fee, unless a deep pocket sponsor is found. On the other hand, if running it unlimited draws more folks, do that.

Power limit discourages anyone who is interested in pushing e-bike tech to new levels IMHO.

I still say let the tires be the limiter, and MAYBE AH of battery, because if you limit the AH to say just barely enough to finish the race safely, you will be limited to how many Watt Hours you can dump into the motor during the race and thus limit the speed/acceleration you can achieve.

The weight limit naturally is a battery limit. Batteries have weight, if you want more batteries, you gotta save weight elsewhere. If you give up some battery capacity, you might save the weight to run the scooter tires with excellent cornering grip, but have to use a lower average power level because of it. Or, if you're running little 700c road bike wheels and tires, you can fit an extra LiPo pack or two on the bike to give you the ability to have more range. etc etc Want suspension? Gotta decide if it's worth trading in the ability to run extra grippy tires? or carry more battery? etc etc.

A weight limit is a natural performance limiter, and a natural way to force the choices in design that make racing and setting up a racing machine so exciting and fun. Keeping the weight limit low essentially means the cost of the battery, controller, motor to be competitive stays decently low. The way I saw it, going from a 70lbs bike to an 80lbs bike, and trying to stay competitive means adding another $500 or so roughly to the bike. Going from 70lbs to 90lbs adds $1,000-1,500 to the bike stay top-tier. Going to 100lbs puts it out the budget I'm willing to spend on an ebike race.




Also, I should add that I plan to win with a brushed hubmotor, and I think my biggest competition will be coming from common off-the-shelf cheap hubmotors. A well chosen $100 roadbike off craigslist + $200 9C hubmotor +$200 controller (tweaked) and $500-750 in LiPo is a recipe to be a serious contender in a bike race at 70lbs, and I think Tiberious plans to fly over here and win with a setup just like that. RC done properly can have a substantial advantage, but it also has it's own share of disadvantages, such as much higher potential for mechanical failures, etc etc.

OK I see your thinking on the weight limit, if we went that route, I say then ONLY do the weight limit, that will make it more of a "run what you brung" type of thing. It is starting to sound fun! I know I will at least be there next year, I don't know if I will be a contender though, since a full suspension off road bike will be a good bit heavier than a stripped down race only bike!

 

[dogman dan]

For example, this now weighs 53 pounds without batteries. It's a fairly light cromoly 26" mtb. So it could possibly carry 20s lipo of 15 ah and just squeak under a 70 pound limit.

You could run a heavier bike with a race that could be finished with 8 ah of battery, carrying 10 ah. You could get closer to 60 pounds for bike weight.

Maybe you could figure out a handicap system based on certain typical weights of bikes and motor systems. Let a guy with a 35 pound bike have 5 pounds more than a guy with a 30 pound bike. So a FS 5304 bike could have 80 pounds? A fs bike with 9c 75, but a hardtail mtb with 9c would have to stick to 70. More weight is a handicap in general, so long as all you can carry is the same size battery.

If everybody brought batteries that could be easily removed from the bike, you could just limit battery weight, and let people run anything they want. 15 pounds of lipo ought to be enough to giddy up. And again, you could allow a few more pounds for a rider that chose headways or whatever. And again, we kinda know what each battery type weighs, so you could actually just look at a bike, and go, " that's over the limit for lipo".

 

[liveforphysics]

Maybe you could figure out a handicap system based on certain typical weights of bikes and motor systems. Let a guy with a 35 pound bike have 5 pounds more than a guy with a 30 pound bike. So a FS 5304 bike could have 80 pounds? A fs bike with 9c 75, but a hardtail mtb with 9c would have to stick to 70. More weight is a handicap in general, so long as all you can carry is the same size battery.

Bike is looking good my friend

Regarding the handicap thing, let's remember it's a race event, not the socialist party equality cruise. If you can put together a setup that makes more sense and gives more advantages than the setups other folks put together, the advantage you get in return for this is better performance.

I don't think you would dig it much if I said, damn! Dogman made aero improvements on his bike, he should have to strap a 10lbs penalty weight on his bike to make it fair for the other who didn't do aero. etc etc.

If you come up with something clever that doesn't break the rules, you should get to exploit that clever thing to give you an advantage in the race (like your aero). The more rules and handicaps, the less incentive to create/innovate clever things.

My $0.02

 

[Whiplash]

ABSOLUTELY, PERFECTLY SAID. ^^

 

[dogman dan]

Well, bottom line, I like the death race rules. Must have functional pedals. Rider must wear safety gear. That way everybody plays, and like all racing, deep pockets can help you win. No escaping that in racing of any kind. Even in one design sailing, deep pockets help with training time costs.

But if limits must be used, I'd like to see them less limiting, like 100 pounds perhaps. If you want to put 40 pounds of lipo at 200v on your bike, cool, we'll really love to see how far you can throw chain with it. 8) Or we really will enjoy it when flames shoot out the cooling holes of your x5. 70 pounds isn't such a tough weight to make really, but it does make combining a heavyish frame and hubmotor difficult, unless the race is short enough to run a 5 ah lipo pack. But a longer race, needing 10-15 ah, is a better test of the build since it has to finish without smoking something.

Chances are, I won't be affording to travel to races other than in Tucson myself, where the rules are still pretty simple. But I see most limiting rules as just keeping somebody out, who could be helping pay that track fee.

In the end, handicaping it is no solution, but a fairly lightweight rule excludes a lot of what people already have. If you really want to make it a featherweight ebike race, then use a 50 pound rule. But for sure, eventually you will have to have rules that keep a 10,000 watt motorcyle out of the "bike" race. I'm not so sure it's that big a problem yet, provided you set some kind of rule allowing a group of riders to protest something too motorcycle like, triggering a vote of all riders present. This would be used if somebody showed up with a bike made from a motorcycle frame perhaps? Then the crowd could give it a thumbs up if it was a whizzer frame or moped, and thumbs down if it was from a racing streetbike.

 

[AussieJester]

Its all been sorted no need to be arguing!...1000watt rule it is

"Face it guys... I've seriously thought this through..."

http://www.motoredbikes.com/showthread.php?t=28177&page=2

KiM

 

[dogman dan]

Great example of a limit that would cut down on the fun. But with enough people that bring a stock kit bike, it could work. Comic relief watching people try to ride a cart track without leaning if nothing else. Maybe some interesting drafting strategy, with long chains of bikes riding with wheels 1" apart.

But for now, too limiting untill you need to sort into classes to fit on the track without too many qualifying heats.

 

[John in CR]

Also, I should add that I plan to win with a brushed hubmotor

Wow, A brushed hubbie? I've got one of those too. How high you planning to overvolt? Blown to keep the brushes alive? Did you start adding up all the weight of a high power drivetrain and get back to a hubbie being not so bad after all?

With that kind of weight limit, I'd probably have to rethink too and go with something like 6 DeWalt 24V tool motors that handle over-volting according to the robot wars guys, 1.2kg for each motor including gearbox for wheel speed friendly output or less than 1kg with higher speed gearbox for going multiple friction drives. A nice cheap solution with easy spares to keep and replace with crazy brushed motor torque using a pair for each rear wheel for AWD.

For the bike I'd have to go exotic to try and cancel the personal weight penalty I give up to the field, and go with a leaning delta trike using a fiberglass/carbon frame along the lines of the Black Max. My hope would be that I could carry more speed through the curves to offset my power to weight disadvantage, since I get to turn like a bike but 3 wheels of traction. Plus my better aero would help my batteries go further, and with a partial shell I lose less skin if I hit the ground.

What distance are the races, so I know how to divide up the 70lbs - bike between batteries and motor weight?

Nah, I'm too lazy for all that. Just lighten one of my ventilated big hubbies as much as possible, put it in a tiny and light wheel, and run it with a crazy current 100V controller. Install it on a stretched and lowered roadie frame reinforced with a wrap or 2 of carbon tape and epoxy plus some aero touches. Load it up with the lightest high C batteries I can find to get to 70lb. Then pray that regen braking and better than average aero being low are enough to offset the power to weight thing. Don't forget the body armor to save my skin, since I won't know what I'm doing other than already being accustomed to a lower bike that being lower will probably hurt me in the curves.

 

[amberwolf]

If it's under 70lbs, and has functional pedals, it's an e-bike.

I guess I don't own any ebikes then. Mine are too heavy. :lol: CrazyBike2 is more than DOUBLE that weight limit. Even if I left all the batteries off it'd still weigh too much.

But if you stuck my bikes in a class with higher power bikes like motorcycles based solely on weight, I'd be so slow compared to them I might as well not come out of the pit.

But I could take some flimsy superlight roadbike frame and cut it down as much as possible, use very narrow tires and wheels, stick a 10KW RC setup on there with Lipo, and beat the crap out of everyone in that under 70lbs category until I killed myself from it coming apart the first time I crashed it (which would be pretty quick).

 

[Whiplash]

But I could take some flimsy superlight roadbike frame and cut it down as much as possible, use very narrow tires and wheels, stick a 10KW RC setup on there with Lipo, and beat the crap out of everyone in that under 70lbs category until I killed myself from it coming apart the first time I crashed it (which would be pretty quick).

HA LOL! THAT'S THE NAME OF THE GAME!

 

[liveforphysics]

Also, I should add that I plan to win with a brushed hubmotor

Wow, A brushed hubbie? I've got one of those too. How high you planning to overvolt? Blown to keep the brushes alive? Did you start adding up all the weight of a high power drivetrain and get back to a hubbie being not so bad after all?

Ehh, think the smallest scooter tire that has a rim that can fit the PMG-132 motor inside it. It's capable of over 40bhp at ~1500rpm And it enables me to run a very simple, light, reliable brushed-type controller.

It means the rear wheel will be around 30lbs or so.... which sucks, but on a light BMX or a light roadbike, that leaves me 40lbs for the bike frame, batteries, controller and front wheel, which is totally possible.

 

[dogman dan]

Guess you are planning on a fairly short race then? Nothing wrong with brushed on a chain drive though, with a blower in the motor. Not an efficiency contest.

And you may very well have a nice tire advantage too.

 

[liveforphysics]

Guess you are planning on a fairly short race then? Nothing wrong with brushed on a chain drive though, with a blower in the motor. Not an efficiency contest.

And you may very well have a nice tire advantage too.

No chain drive, other than what you can pedal with if you wanted to pedal.
No fan either. A true direct drive brushed hubmotor. Just layed out in a less compact and heavier way than using the rotor as the spoke flange for the rim like a traditional hubmotor, but still a hubmotor.

 

[liveforphysics]

But for sure, eventually you will have to have rules that keep a 10,000 watt motorcyle out of the "bike" race. I'm not so sure it's that big a problem yet, provided you set some kind of rule allowing a group of riders to protest something too motorcycle like, triggering a vote of all riders present. This would be used if somebody showed up with a bike made from a motorcycle frame perhaps? Then the crowd could give it a thumbs up if it was a whizzer frame or moped, and thumbs down if it was from a racing streetbike.

WTF? Hell no!! This is exactly the sort of thing that ruins the incentive to innovate. I wouldn't even bother to enter a race where they could just decide to vote you out of the event over no rule violation. Spend a couple grand in logistics to make a racing effort, and another few grand on building a bike to meet the rule requirements only to have somebody tell you your bike is too good to race... The whole concept makes my blood boil...

You make rules in advance, you establish the definitions for the words used in the rules (to avoid double-meaning issues), and if the bike falls inside of the rules, it's legal to run. The idea that you can ban somebody because they managed to fit something into the rules that gives them an advantage is some Harrison Bergeron level uber-socalism. If somebody thinks it's a worthwhile thing to use a 30lbs motorcycle frame over a 10lbs bicycle frame, and they do it, and it has pedals, and it doesn't exceed 70lbs, then hey, good luck to them, they are going to need it.

70lbs is plenty! A 100lbs limit would be insanity, it would mean bike prices in the >$5,000 range to be top-tier, and it means a sh*t load of risk and danger on a light kart track (because you're going to have 50hp bicycles!). 70lbs bikes mean cheap, practical, and decently suitable for a kart-track.

The idea behind racing is to be a challenge.

If the ebike somebody made as a commuter doesn't duck the 70lbs, hey! Perfect! It's a commuter not a racer, and if they want to do a racer, they are going to have to figure out how to drop weight in various places to get there. AKA, they are faced with a challenge to over come, this is GOOD!

The prep and building and designing the bike, practiceing and tuning the setup should be 99% of the effort in making a good race attempt. The racing itself is like the 1% effort that results in a large amount of the fun and reward.
If you want 1% effort, and 99% fun, you do a cruise ride on a nice scenic road with guys on commuter ebikes, and nobody burns up stuff or breaks down or gets hurt, and you have a great time and enjoy a way better fun to effort ratio and cost to fun ratio than anyone focused on trying to win a race.

My $0.02

 

[docnjoj]

Hey John! No trikes! I already asked.
otherDoc

 

[liveforphysics]

Hey John! No trikes! I already asked.
otherDoc

If you could get enough trikes together, you could always do a trike class.

 

[docnjoj]

Now that would be interesting, LFP. 100 lbs weight limit?
otherDoc

 

[liveforphysics]

Now that would be interesting, LFP. 100 lbs weight limit?
otherDoc

It would be interesting, the lap times should be much much faster than the bikes.

As far as the rules for a trike race, I'm not going to be racing in it, and I've got 5mins of total trike experience, so I've got no place suggesting rules for it. The rules for it should be something participating trike guys to get discuss and decide.

 

[docnjoj]

In Europe they race trikes all the time. Hans Siede the developer of my trike used luge tracks in the summer for time trials down mountains. Nuts! I don't have the youngness and foolishness (Guts?) to race anymore but racing trikes is like wheelchair racing, but gentler.
otherDoc

 

[dogman dan]

Sorry to yank your chain again LFP, your venue your rules. If I could afford the trip, my bike would make the 70 pound weight. That weight limit will definitely keep out motorcycles with pedals.

We just have different ideas of why we are racing is all. You could though, open the track to practice laps for those who's bikes exceed 70 pounds. That may be the best compromise, guys on commuters like I took to the death race last year aren't there to win. They just want to see if they have the stones to make the corners and pose, like I did at the DR. That's not a problem during practice time if there is plenty of room on the track for em.

Have fun finding out what the melting point of those brushed hubs is. It'll be good to have somebody to test that for us.

 

[liveforphysics]

Sorry to yank your chain again LFP, your venue your rules. If I could afford the trip, my bike would make the 70 pound weight. That weight limit will definitely keep out motorcycles with pedals.

It's kinda a touchy issue for me, having been in the situation where I've invested thousands of dollars, and every bit of free time for weeks to get a racecar together for an event, take days off work, transport the car to the event, then get told it can't race for some bullsh*t reason... It's worse than just pissing away thousands of dollars, because it also pisses away all the things you sacrifice doing in life to give up all your freetime towards getting something ready for an event.

We just have different ideas of why we are racing is all. You could though, open the track to practice laps for those who's bikes exceed 70 pounds. That may be the best compromise, guys on commuters like I took to the death race last year aren't there to win. They just want to see if they have the stones to make the corners and pose, like I did at the DR. That's not a problem during practice time if there is plenty of room on the track for em. .

If there is free track time, then of course run whatever people want to run and have a good time. Can't have a main event for the folks that come for a serious race to have to be making additional passes than needed though, so a main event has gotta be just for the folks who prepped and practiced and came out to make a commited serious effort to win (the purpose of a qualifying heat of course).

Have fun finding out what the melting point of those brushed hubs is. It'll be good to have somebody to test that for us.

Lucky for me, the perm 132 has pretty good documenation about it. Rated for something like 19hp output for 10mins continously! Burst rates over 40-50hp!
http://www.electricmotorsport.com/store/ems_ev_parts_motors_pmg132.php

Here is an example of a go-kart powered by one. This uses a belt drive to the rear axel, where I will just be mounting the rear wheel right onto the output shaft (making it a hubmotor).
[youtube]sw9hN43YSo[/youtube]

 

[dogman dan]

Ahhh, now I get it. I just didn't know you could get those in a hub motor. I was picturing in my head, something that was made for the typical electric scooter in the moped class.

So you are building an electric motorcycle, but it's gonna weigh 69.9 pounds. Awesome! Sounds like it will definitely blow away the capabilities of bike tires. Shows how different we are thinking. I just feel bike, means bike tires, but if it pedals by god it's a bike. 8)

Front hub or rear? Won't it be a bit difficult to cram in even a fixie cog if rear? I suspect the rear end will be a bit modified to fit it? Can't wait to see vids of it, or better still, for you to take the death race on it.

 

[liveforphysics]

They don't come in a hub, I gotta turn it into one, and mount a pedal drive sprocket/freewheel into the mix as well. Definately rear wheel drive.


If the perm 132 ends up being too heavy to fit a useful amount of battery with it to make it worth while running such a boat-anchor of a motor, then my second plan is a light weight roadbike with a friction drive to an RC motor, something super simple like Kepler's drive setup, which should enable me to have plenty of weight for all the battery I will need, be very simple to make, and I likely won't be over 55-60lbs, so the 10-15lbs weight advantage over the other bikes in the class should be a substantial advantage.

Lots of choices... lots of choices... and so little time off work to tinker!

 

[dogman dan]

Oh yeah, but you have the skills and the workshop to do it, if anybody can. Finally got my 72v front 9c running, and so far no issues with too much power to the tire. You bet it will melt rubber from a standing start, but from 25 mph, it feels fine to hit full throttle. You can really feel that pull in the corners now! I remain convinced that front drive is going to be a huge advantage in corners. But at some point, the wheel is going to bend that fork in half. So a few more pounds for thicker forks.

 

[Whiplash]

Yeah, I would also keep an eye on the Steer tube, if its alloy, buy some crack detector like they use on engine blocks, you spray the area with this red dye, then carefully buff it off, then spray developer on it to show cracks. Chromoly when its thin like that will let go quick, not bend slowly, and you will end up with a face full of asphalt if you are not careful! That is the only real reason I would not personally do a high power front drive, ever..