E-bikes running with the Gas-bikes

[etard]

In 2 wheel roadracing, being low is a disaster, and having a higher top speed down the back half of the straight has a tiny, roughly useless difference in laptime.

Luke, that statement is hilarious coming from you my friend! :lol: You had a 15 mph advantage over Paul down the straight, I think in the 1000 watt class most would probably top out at 30 mph. Having a huge aerodynamic advantage after 20 mph will allow me to disappear like you did on the straights. Then if I could hit 40 mph before braking, I could probably gain a position or two on each lap, everything else the same. If that isn't a huge advantage, I don't know what is. :? I understand having your weight forward ( to a point) but high I'm not understanding. Picture of a lowracer:

Looks pretty high and forward to me. Perhaps too forward? Heck, if it starts to endo too much, just stick a leg out! :wink:

What about something like this:

 

[AussieJester]

@etard...i can tell you in the speed trap times for motoGP
some of the riders finishing off the podium often have as much as 15-20km/hr
more speed down the straights... Braking, cornering and getting the power down to the ground and out
of the corners is where you make up time on a race track...

Like to see you corner a low racer as quick as PaulD makes a mountain bike go round a corner...

KiM

p.s That fluff on your chin erm "soul patch" will have to be extended and a few more kilos put on the "aero"-belly before your
"allowed" a license to ride a low rider to etard...(sorry couldnt resist...agaian)

 

[liveforphysics]

In 2 wheel roadracing, being low is a disaster, and having a higher top speed down the back half of the straight has a tiny, roughly useless difference in laptime.

Luke, that statement is hilarious coming from you my friend! :lol: You had a 15 mph advantage over Paul down the straight,

And what did it get me? I would pass PaulD down the straight, and then he would pass me back in the twistys, and I would exit a few seconds behind him and struggle to try to pass back before the end of the straight. I could accelerate perhaps 3x harder than he could, and it was only worth anything for a 4 second period out of the 81seconds it took to go around the track.

I think in the 1000 watt class most would probably top out at 30 mph. Having a huge aerodynamic advantage after 20 mph will allow me to disappear like you did on the straights. Then if I could hit 40 mph before braking, I could probably gain a position or two on each lap, everything else the same. If that isn't a huge advantage, I don't know what is. :?

When you get your speed increase from aero rather than power, your F=MA is the same, so you only start to have an advantage as your speed gets very high, which it climbs up as slowly as anyone elses speed. This means the time when you get a bit more speed is at the end of the straight, which is exactly the LAST PLACE you want to have a bunch of speed, because the total time you get to travel at that speed is #1 only a second or two at the most, and #2, you have to start your braking zone sooner than anyone else, which is a prime point for getting passed back if you managed to use that 2 seconds of improved speed to do anything with it.

Look at it this way, if you can come off a corner exit at 5mph faster, you carry that 5mph advantage for the entire straight away, like perhaps 10 seconds or whatever of having a 5mph advantage. It shaves more time off your laps as getting a magical 25mph speed advantage for the last 2 seconds by a HUGE margin, because it doesn't have a large effect on your braking point.

You will ALWAYS be faster if you can do anything to exit a corner at a higher speed, or to be able to accelerate hardest when you're at low speeds, just having exited a turn, than to be able to pour on power or a big speed advantage toward the end of the straight away.

If you look at drag racing the importance of accelerating early becomes painfully clear. If I run the whole quarter mile, I may get a 11.0 at 115mph. If I run just HALF WAY down the track and then coast to the quarter mile, I run an 11.4 at 105mph. If I put on street tires so I get a shitty 60ft time, I run a 12.0 at >120mph.

I understand having your weight forward ( to a point) but high I'm not understanding. Picture of a lowracer:

Looks pretty high and forward to me. Perhaps too forward? Heck, if it starts to endo too much, just stick a leg out! :wink:

What about something like this:

Did you see the couple of gas guys trying to ride low-racer bikes around the track??? It's just painful to watch. It's simply impossible to turn well on 2 wheels when you're low, and extremely impossible when you're low AND long. They had hot engines, and were getting creamed by recreational riders pedaling along leisurely. For an opposite perspective, did you notice Zombiess riding the tiny short wheel base childs bike with a massively raised handbar and seat, so it looked almost comical? The guy MOWED THROUGH bikes in the corners, massively higher exit speeds on a machine with relatively low power, and it performed really really well. You don't want your wheel base a bit longer than you need to enable you to use the power you've got without wheeling over backwards. My next bike build is going to have a shorter wheel base even, because I've learned a lot of lessons on the importance of power vs handling over the past few races.

2 wheeled vehicles are NOT cars (which virtually always have higher handling limits when lower). A 2 wheel vehicle does not get to transfer normal force loading from one side to the other, it can ONLY TURN by cantilevering a weight off axis equal to the amount of turning g-force you're trying to achieve, if you can't balance those things, then you cant sustain the turn at that rate.

Guys on low bikes like that would need to climb up out of there seats and sit there ass on stools like 2ft tall off the seat just to even be physically capable of cantilevering the mass needed to turn like a normal bicycle.


This stuff isn't even on the table for debate, it's just basic physics, well proven on the streets, racetracks, and zillions of real life examples.

 

[etard]

AJ,

Not all of us have the strong chin like Micheal Douglas. :lol: The rest of us must make do with what we have. And I like to call it a "Flavor Saver" :wink:

Back on topic, I'm talking a SAFE 1000w limit here, where 200 watts pedaling and 100 watts worth of aerovantage gets you on the podium with your balls hanging out, i.e. Lycra!!

Edit:
Ok,
I missed you last post Luke, you have a very good point about exit speed out of the corners, I will have to rethink this whole lowracer idea. To me it was more of an excuse to build one out a bmx I have here that would make a good donor. It just seems like the aero advantage kicks in at about 20-25 mph and that is about the exit speed for the last turn at Grange, at least at 1000 watts. So wouldn't a streamliner pick up speed quicker than a standard bike? I also see all these guys on Herr riding these super low and long recumbents and I ha e to believe it has some sort of advantage to negate the possibility of being squooshed on the road. They cant be that hard to ride, right? I have never actually seen one in person and I missed the action at Grange on the track (Thud and I got thre as everyone was leaving). I didn't even getto see Zombiess bike, but it sounds a lot like the Jr. Brute!

 

[AussieJester]

AJ,

Not all of us have the strong chin like Micheal Douglas. :lol: The rest of us must make do with what we have. And I like to call it a "Flavor Saver" :wink:

It iz true Etard, not all can be as good looking as I it is a curse i have to carry around
a burrdon if you will ROFL@ flavour saver :lol:

I think the formulae for the best racing e-bike is a ~6in extention on a dirt jump 24in style frame running 20in rims with
16in motorcycle tires throw some hydro brakes on there (off a scooter or pit bike if your Lukes size)
a front suspension fork with shortened spring set <--(avaialble off the shelf @ CRC) lot of lipo
and ~6kw peak power output mid mounted motor...OH and prolly the most important thing, BiG BALLS to carry
speed through the corners ala PaulD...

KiM

 

[liveforphysics]

I think the formulae for the best racing e-bike is a ~6in extention on a dirt jump 24in style frame running 20in rims with
16in motorcycle tires throw some hydro brakes on there (off a scooter or pit bike if your Lukes size)
a front suspension fork with shortened spring set <--(avaialble off the shelf @ CRC) lot of lipo
and ~6kw peak power output mid mounted motor...OH and prolly the most important thing, BiG BALLS to carry
speed through the corners ala PaulD...

It's so funny that you would say that, because it's exactly what I also think is the optimal kart track race bike, and exactly what I plan to build for my next bike, to the T.


Etard- As power levels get lower, whoever has the ability to conserve more speed will dominate. At the speeds a bicycle can see on a kart track, aero is going to fetch you nothing, and if the setup impaires your ability to ride the bike in any way, or if it even adds 5lbs to the bike, it's going to be a net loss to the vehicles performance on a kart track, even if on an open highway it would double the top speed.

 

[MadRhino]

A cart track definitely gives advantage to cornering ability. High COG, light weight, braking precision, tire performance and suspension tuning are what to look for.

 

[gtadmin]

Why is having a higher CoG better? I've just done a rudimentary force / moment diagram and I can't see where the difference is. Could someone explain it for me please?

Edit: Ignoring the width of the tyres (for a bicycle)

 

[MadRhino]

Why is having a higher CoG better? I've just done a rudimentary force / moment diagram and I can't see where the difference is. Could someone explain it for me please?

Edit: Ignoring the width of the tyres (for a bicycle)

In high speed cornering, one needs to transfer alot of weight inside. Having the weight high makes for easier transfer, with less amplitude of movement required to move the necessary weight. Also, less amplitude means better traction in the turn, because you don't have to ride as much on the tire edge. Then, it makes for faster recovery too, when you have to straighten the weight exiting the corner.

Compare the handling of a trial bike and a road racer: The trial bike has the COG very low, thus your movement is acting with leverage and you have to move alot to change the balance. This makes for high precision, but handles nicely only at slow speed. A road racer has high COG, doesn't handle with precision at low speed because the weight transfer is over-reactive, but being reactive gives it a great advantage at high speed, where weight transfer has to be done quickly.

Proper suspension tuning gives a big advantage too. Your front suspension transfer weight on the front wheel when braking, and shortens the wheelbase at the same time, to improve cornering radius. Then it straightens to tansfer the weight on the rear wheel in the exit to give better traction under acceleration. Balance between rear and front suspension, adequate rebound and compression setting, quickly set your bike's in the optimal state of balance. If it goes down too low in the corner entrance, it will release traction from the rear wheel, and if it returns exagerately on the exit it will release traction from the front wheel.

Everythin in cornering ability, is about how fast the proper balance can be achieved, laterally and longitudinally.

 

[gtadmin]

...
In high speed cornering, one needs to transfer alot of weight inside. Having the weight high makes for easier transfer, with less amplitude of movement required to move the necessary weight. Also, less amplitude means better traction in the turn, because you don't have to ride as much on the tire edge. Then, it makes for faster recovery too, when you have to straighten the weight exiting the corner.

Compare the handling of a trial bike and a road racer: The trial bike has the COG very low, thus your movement is acting with leverage and you have to move alot to change the balance. This makes for high precision, but handles nicely only at slow speed. A road racer has high COG, doesn't handle with precision at low speed because the weight transfer is over-reactive, but being reactive gives it a great advantage at high speed, where weight transfer has to be done quickly.

Proper suspension tuning gives a big advantage too. Your front suspension transfer weight on the front wheel when braking, and shortens the wheelbase at the same time, to improve cornering radius. Then it straightens to tansfer the weight on the rear wheel in the exit to give better traction under acceleration. Balance between rear and front suspension, adequate rebound and compression setting, quickly set your bike's in the optimal state of balance. If it goes down too low in the corner entrance, it will release traction from the rear wheel, and if it returns exagerately on the exit it will release traction from the front wheel.

Everythin in cornering ability, is about how fast the proper balance can be achieved, laterally and longitudinally.

I understand that there are "use" differences between a trail bike and a road-racer that enable the road-racer to corner faster on a race track, but given the same two bicycles with the only difference between the two is the battery placement (one high = higher CoG, one low = lower CoG), why will the one with the higher battery placement corner faster that the one with the lower battery placement?

Edit: don't overlook that CoG refers to the bike and rider combined

 

[dogman dan]

Once you've been around the kart track on one of these bicycles, you start to get it fast. It's hard to get it just how tough those tracks are. 25 mph is actually pretty difficult on some of those corners. And the leaders are smoking through em at 30. Plus the next one is never much more than 5-10 seconds away.

Maybe you don't get the why of it, but it just becomes so obvious to you that your "thought they were superb" cornering skills need work. And you can really see the struggles of the guys who get the balance of their bike wrong.

You still outcorner the doofuses out there, but somebody on that track corners better than you, and pouring on more speed in the straight just puts you in deeper doo doo when you get to the corner. That's how I got my ass handed to me in the DR last spring. Passing that guy, but then overcooking the corner and taking crappy lines as a result.

Re the scheduling, the good months to have a race in the desert are what they are. Be happy they weren't the exact same weekend. Be even happier you are healthy enough to ride either one.

 

[Tiberius]

....
PaulD and I have talked for hours together about how to make fair classes for gas and electric bikes. It always comes back to Tiberius' original suggestion of weight maximums. Why weight? Because you can check it in 10 seconds as a bike is rolling up to go on. It balances modifications amazingly well. If somebody wants to run motorcycle tires for example, well, they were a 7.5lbs addition to my bike over bicycle tires, so I would have to run either less battery, a lighter controller, a lighter motor, etc to still make the weight. As a race gets longer, ebikes fall victim to battery weight in a drastic way, as there energy is single use disposable liquid, and ours is an elaborate reusable container for electrons.

We discussed having ebikes weigh-in with no battery on board, and gas bikes weigh-in with no fuel on board. It does allow for races to stay balanced at any practical distance.

Where it fails badly, is rider weight impact. This is why every karting class always weighs kart/rider together, and lead is bolted to the karts that fall under the minimum. For bicycles, this isn't really a safe practice, and would get pretty extreme with realistic 100lbs differences between riders body weights.

Likewise, heavier riders need heavier brakes, shred tires faster, and require more power to accelerate at a competitive rate. For example, PaulD's bike was amazing with his light body on it, but when I ran some laps on it, it was flexy, badly under powered, and the brake faded unsafely for me while only riding 7/10ths intensity.

This brings us to bike weight as a percentage of riders body weight. Why? Because it's measurable in seconds with a sub 1% margin of error, it lets big guys run safe bikes and little guys run safe bikes, without giving a big advantage to either, and it lets gas bikes run against electric bikes. To prevent anyone from being a huge 400lbs guy on a motorcycle, you have a fixed bike weight cap at something like 100lbs (or whatever line you want to say is when a bicycle stops being a bicycle).

Where does it fail? Non-race bikes, like big heavy cruisers with crap power, both electric and gas, end up not being fairly classed at all. However, there is an easy solution, if you brought a non-race bike and just came to have fun, then have a fun class for those folks to go ride.

Also, to touch on the topic of this thread, I think the concept of running ebikes by themselves, or 2 stroke, or 4 stroke or whatever by themselves is really really dumb. I would never even bother to attend an event that was just e-bicycles, it has no appeal to me at all. 100% of the appeal is in different types of bikes competing against each other. I don't actually think ANYONE likes grouping races by bike type rather than by folks that want to race against each other. It's like going to drag racing events, domestic only races and events suck, nobody cares, import only races and events suck, nobody cares, but DOMESTIC VS IMPORT events draw huge crowds, everybody is emotionally wrapped up in the races for one team or the other, and the races are 10000 times more exciting to watch.

IMHO, to do this right, you have 2 classes, possibly 3 classes (if you want 2 different weight groups). You have the fun-run folks who are just there to enjoy going around a track and didn't bring race bikes, and they don't weigh-in, they just go out as a group and ride. Then you have the class for people who come to race on things made for racing, and they have to weigh-in and meet the rider/bike weight spec. A light weight group for folks with perhaps under 0.4lbs of bike weight per 1lbs of rider, and a middle/heavy bike group for riders with under 0.55lbs of bike per 1lbs of rider (or whatever is determined to work out well).

Power can't be measured while on the track for gas bikes, and it's damn easy to fool with electrics. Weight can be measured with dirt cheap equipment to extremely reliable numbers, everyone can check at home with a bathroom scale to see where they are at so there are no surprises at the track. Set the values so it forces bicycle to be bicycles, and let the weight maximum be the limiter for the engine/motor/CVT/gearing/controller/wheels/tires etc.

Thanks Luke,

I was about to wade into the thread, but you've done it for me. Yes, weight is the key.

I'm not so sure about this percentage of the rider's weight though. I try to look after myself and I want my reward for being 150 lbs instead of 200. Surely you would also have to have naked weigh-ins to stop people stuffing their pockets with LiPo.

Oh, this is making me want to go out and race....

Nick

 

[Thud]

So you guys are finaly catching up on road race design LOL:
AJ said:

I think the formulae for the best racing e-bike is a ~6in extention on a dirt jump 24in style frame running 20in rims with
16in motorcycle tires throw some hydro brakes on there (off a scooter or pit bike if your Lukes size)

luke says:

It's so funny that you would say that, because it's exactly what I also think is the optimal kart track race bike, and exactly what I plan to build for my next bike, to the T.

The only weight limits should be minimum's IMHO.

lets see, where have i seen a bike like that???? oh yah! its in my basment getting covered in cob webs!

This thing cut under PaulD in turn 12 & embarrassed the morini at the end of the front straight coming out of turn 2 on only one over-loaded motor. Aprill 20011
(pure corner domination & carrying the little speed it was making)
the only question is, do I puss out & put a perm132 in it (easy road to shallow glory)...or re-fit the hobo's.

I look foward to our next meeting on the track......
remember..the corners are MY HOUSE & that includes the braking to get me there before you :wink: ...I allways brake last.....allways!

If this fat boy finds the budget to make the next aprill event in Tuscon or Calli....you will have to fight me for position....thats a gaurandamntee my friends.
I call dibb's on the Nicobe pits!

 

[SoSauty]

I'm jumping in and concluding the orginal topic from pages 1-3.
Thanks to everyone who chipped in (pages 1-3). Thought I’d give everyone an opportune to openly voice their concerns. Every individual perspective was informative. Here’s a summative list of the concepts you no doubt have already read about:
1. Bracketing by lap times
2. Bracketing by top speed
3. Battery/controller power level,
4. Power inputted
5. Power outputted
6. Amount of battery capacity mounted
7. Chip or watt meter power level
8. Weight of race bike or bike/rider weight ratio
9. Volunteer self-classification
10. No grouping at all
11. Entry class and everyone else class
Bear in mind that we are still motorbike racing guests. One theme that popped up thru out was ‘mixing e-bikes with the gas bikes’. Several ES PM’s were sent, 1 from the MB forum, expressing excited support of mixing lo-powered e-s and small 4strokes. The clamoring was for a lot more mixing, but the 1 class is neat. Seems 1000W is encouraged but other e-levels suited to sub 35mph small 4stroke speeds would likely fit in.

About revising racing categories; several are persuasive, except the part about us or me being f***ing fool(s) Hey, glad to take a bullet for ‘ole MBR. Some of us aging e-gear-heads are concerned about the rider weight to power ratio. The bracketing by radar clocking would be doable; we already have the Grange data. I remain hopeful, yet cautious due to the reality of volunteer labor requirements and widespread acceptance by our wider motorbike community, as to some racing category revisions as the sport grows.

To ES, LSU is playing Crimson Tide this weekend, and I have a life to return to. I likely won’t be reading this thread in the future. PM me if you wish to run a Joby type motor or express any follow up concerns and I'll respond.

Oh and to give a heads up to some, and particularly Luke. The rule of <9K; no 8”, 7”, 6” diameter electric motor will be classified as ‘unlimited’ remains. Paul_D took top honors with a 3.15” motor. If you or anyone wants to run in the coming “AGK Monsta’ Race”, you gotta run a 5” or smaller electric.

Carry on
Will aka SoSauty aka Smoke

 

[AussieJester]

Haha close ThudSTeR, imo though an inch our two of front suspension and mounting the packs lower would improve the Bully...DEFINATELY dont puss out and put an e-motorcycle motor in it...im sensing a two speed with rewound Turngy ca-120
In the Team ThuD Bully's future though
That said the bully is easily the best e-bicycle race bike
I have seen :wink:

TEAMThuD 8) FTMFW

KiM

 

[liveforphysics]

I'm jumping in and concluding the orginal topic from pages 1-3.
Thanks to everyone who chipped in (pages 1-3). Thought I’d give everyone an opportune to openly voice their concerns. Every individual perspective was informative. Here’s a summative list of the concepts you no doubt have already read about:
1. Bracketing by lap times
2. Bracketing by top speed
3. Battery/controller power level,
4. Power inputted
5. Power outputted
6. Amount of battery capacity mounted
7. Chip or watt meter power level
8. Weight of race bike or bike/rider weight ratio
9. Volunteer self-classification
10. No grouping at all
11. Entry class and everyone else class
Bear in mind that we are still motorbike racing guests. One theme that popped up thru out was ‘mixing e-bikes with the gas bikes’. Several ES PM’s were sent, 1 from the MB forum, expressing excited support of mixing lo-powered e-s and small 4strokes. The clamoring was for a lot more mixing, but the 1 class is neat. Seems 1000W is encouraged but other e-levels suited to sub 35mph small 4stroke speeds would likely fit in.

About revising racing categories; several are persuasive, except the part about us or me being f***ing fool(s) Hey, glad to take a bullet for ‘ole MBR. Some of us aging e-gear-heads are concerned about the rider weight to power ratio. The bracketing by radar clocking would be doable; we already have the Grange data. I remain hopeful, yet cautious due to the reality of volunteer labor requirements and widespread acceptance by our wider motorbike community, as to some racing category revisions as the sport grows.

To ES, LSU is playing Crimson Tide this weekend, and I have a life to return to. I likely won’t be reading this thread in the future. PM me if you wish to express any follow up concerns and I'll respond.

Oh and to give a heads up to some, and particularly Luke. The rule of <9K, no 8”, 7”, 6” diameter electric motor will be classified as ‘unlimited’ remains. Paul_D took top honors with a 3.15” motor. If you or anyone wants to run in the coming “AGK Monsta’ Race”, you gotta run a 5” or smaller electric.

Carry on
Will aka SoSauty aka Smoke

And yet, I don't feel like it's a mocking attempt, I think it's a genuine effort, but somehow completely blinded to realities of racing. Which seems so weird, because I know you've shown up and raced at 3 event or more if I'm not mistaken.

Did you ever read Tiberius's original ebike racing proposal? It was pretty much flawless. As you would expect from a guy who has decades of various racing experience of many types, and happens to be a brilliant physicist, and a realist. It pretty clearly outlines why #1 through 7 are impossible to yield good results in real life, after he had experienced years of seeing people try to use those metrics for various racing, and seeing it all fail horribly. I recommend reading it. I've only got a decade and a half of 5 different types of racing under my belt for experience, and it all has lead me down the path that ends up at roughly exactly Tiberius's proposal (only disagreement being body-weight influence on bike weight).

 

[Evoforce]

Dogman, because you weren't at the races you missed out on the real politics that were going on about the racing schedule. I don't expect you to get it. But the people in the know have a clear understanding.

 

[Tiberius]

I would refer you to the words of my nine year old daughter.

Back in the summer, I took her to see an air race. We don't have proper air races over here any more; we only have handicap races aimed at making the sport more inclusive and accessible. I was half way through explaining the system, where the handicappers stagger the start times and try to arrange for everyone to arrive at the finish line together, when she interrupted me with a withering stare.

"That's not racing, Dad. Racing's about who's the fastest."

Nick

 

[gwhy!1]

This is interesting and very apt at the moment as the introduction of small electric trials bikes to be allowed to compete with gas bikes is causing a few problems on the trials scene. The ACU ( auto cycle union ) are struggling to come up with a set of rules that will suit everyone. There will never be a course (track side ) dyno for any bikes that are questioned. here is some thing that has happened recently in a round of the British youth championship , the person that won the round was on a 20" wheel trials bike but should have been riding a larger wheeled bike, the lad that came second ( on a regular gas bike ) contested the result and the electric bike was impounded ( and taken away for testing at the expense of the rider) on the grounds that the electric bike had more power than the gas bike, the gas bikes for this class should be no bigger than 50cc ( the electric bike has a 1.2kw motor ).. what I have suggested is that everyone using a electric trials bike should be fitted with a watt meter ( if riding for reward, supplied for the event by the acu ), a highly tuned 50cc geared gas bike produces around 4-5kw so I think this should be the limit for a electric bike. At the moment the rule book states that a electric bike (motor) is rated for continuous use i.e. 1.2kw , now this is a unfair rule as we all know that a motor can be pushed as much as it can take before it burns up. This rule as it stands also makes it very hard to police... I vote for apples and apples. if a highly tunned 50cc bike can produce 4-5kw max then this is want the max should be for electric bikes also and very easy to police.