Pikes Peak, Electric Mountain Climbers...

[Paul_G]

Dual carbon rotors should be fine for that downhill

http://www.bikerumor.com/2011/09/24/gatorbrake-eight-piston-hydraulic-disc-brakes-with-carbon-fiber-rotors/

 

[neptronix]

The idea of going downhill on 7%-14% grades with plenty of twisties scares the shit out of me.

Will have to confirm that that's an official part of the race next year.

 

[dogman dan]

We used to gravity race 10 miles of 8-10% on ten speeds in the 70's. Only losers and pussies ever touched a brake lever. Besides it was often raining, so brakes wouldn't work much anyway.

Unzip the coat almost all the way and sit up if you are going too fast. I don't see it as that big a problem, the parachute idea is fine, just tuck a windbreaker somewhere to have on the way down. I don't have the same stones now, 35 years later, so I'll just unzip. You could just short your phase wires for the ride down, assuming you waited for the hub to cool off.

I think the race down is just a bragging rights thing among the lycras. Back down, the pedalers may have a big advantage with areo bars and such.

 

[MadRhino]

The idea of going downhill on 7%-14% grades with plenty of twisties scares the shit out of me.

Strange how people are different, that descent is the only thing interesting to me, and I'd be using battery power at many stretches down this road.

 

[itchynackers]

I regened on a 12% downslope and never got over 15mph. That is just activating the regen, not using the mechanical disks. I doubt anyone would go so fast as to fly off the mountain. I would be more worried if I had a parachute behind me,...and there was a gust of wind.

 

[liveforphysics]

Just a little reality check on how small the radius of a 16" magic pie is vs a 26" bicycle rim.

Magic pie winding pattern and winding factor.

 

[bigmoose]

Luke on the pix above, where would you put the halls? In the slots Anfang A, B & C?

 

[liveforphysics]

Luke on the pix above, where would you put the halls? In the slots Anfang A, B & C?

Not sure my friend, but I will ask Biff when he gets back.

 

[adrian_sm]

Ok, just wanted to make sure I was making myself clear, sometimes I don't word things clearly on the net. :lol:

I know you guys are talking mainly of doing a cheap build to really put it to the highly priced opti bikes, so that is where the hub motor is really a big factor. But how do you think an RC motor setup would do on this climb? Cost not being a major design of a bike build. I would like to take the bike I'm currently building to this event as well. Would there be any negative reasons to not use an RC build for this climb? (Besides cost.)

For me it is all about the continuous torque capacity for the motor. If you can gear an RC such that it stays within the maximum continuos torque it is able to sustain you should be okay. Even better if you can improve things by helping the cooling in passive or active ways.

We just need some better data on the torque/phase current these motors can sustain without melting.

- Adrian

 

[Jay64]

I am in the process of trying to get one of these motors running. Once I do, I have 4 of this one type, so I do plan on doing an endurance test on one of them to try and see where the limit might be. I also have a Nuvinci hub that will help to keep it in the safe zone for the continous torque.

 

[neptronix]

Just a little reality check on how small the radius of a 16" magic pie is vs a 26" bicycle rim.

Ancient Zen koan: what is the sound of one pedal scraping...

 

[liveforphysics]

For me it is all about the continuous torque capacity for the motor. If you can gear an RC such that it stays within the maximum continuos torque it is able to sustain you should be okay.

Nope.


If you need 1.5kw-2kw continuous output, and you've got a 93% efficient RC motor, you're never going to get up the mountain unless you've got water flowing into it or something similarly extreme to cool it.

 

[Jay64]

Luke, so you are saying that any of the RC motors can't make it up the hill, regardless of gearing or windings, without having some type of water cooling or some other exotic cooling system?

 

[gensem]

When did Luke turn blue? I noticed today -.-

 

[liveforphysics]

Luke, so you are saying that any of the RC motors can't make it up the hill, regardless of gearing or windings, without having some type of water cooling or some other exotic cooling system?

After spending lots and lots of time on the dyno testing various things, yes, that's my conclusion.

RC bikes are king of ripping around town and having fun, off-road stuff, and road-course racing.

But continuous power is an ugly ugly thing, that is really like 90% about having massive area that is open to massive airflow passing over it. This means the physically largest surface area motor that is able to be open to airflow is going to be king of the continuous.

 

[Jay64]

Ok, I guess I misread the earlier parts of the thread. Or just made too many assumptions. I had thought that you guys were going with a hub to do a good bike for as cheap as possible to have a great performance to cost ratio. But you are saying that the hub is the way to go to get the best performance to last the whole climb. What are your thoughts on the 9 continents motors for abuse like this?
You gotta forgive me, I've lived in Florida ever since I got into EVs and the only hills I can find around here are the over passes on the bike trails. :lol: :lol:

 

[Jay64]

Actually, I have been so caught up in the RC stuff lately, and have done a few hubs, that my mind went with those two as the only motor choices. How would a motor like a Mars or agni brushed motor handle that climb geared for about 27mph?

 

[LI-ghtcycle]

Just a little reality check on how small the radius of a 16" magic pie is vs a 26" bicycle rim.

W00t! Three Motors and 100lbs of Lipo Eh? that should do it! That means you'll get there 3x as fast right? :lol: :lol:

 

[itchynackers]

Unless you can hide it and keep it on the down low, Luke will say that Opti wins. "See, it took a motorcycle motor to beat an Opti!"

 

[Jay64]

I'm not worried about beating the opti's in a fair fight. Actually, I'm not really concerned with beating the Opti's at all. There are lots of members here who can definately build a comparable bike to the Opti's for a LOT less money. I will leave the Opti beating up to those members, and I will be cheering the ES Opti Beating Builds the whole way. I just think this is a cool event, and I definately would like to participate in it. I'm just going through all the motors that I currently have and trying to see if one of them would be up to the task of this event. I would prefer to just put something together that I already have, rather than buy a bunch of new stuff just for this one event. If I happen to beat the Opti's, that's great, if not, as long as I make it to the top without breaking, that would be great too.

 

[adrian_sm]

For me it is all about the continuous torque capacity for the motor. If you can gear an RC such that it stays within the maximum continuos torque it is able to sustain you should be okay.

Nope.


If you need 1.5kw-2kw continuous output, and you've got a 93% efficient RC motor, you're never going to get up the mountain unless you've got water flowing into it or something similarly extreme to cool it.

Do you have some data to share? If we know what amount of waste heat they can dissipate, it will help being able to design them to survive.

 

[John in CR]

Just a little reality check on how small the radius of a 16" magic pie is vs a 26" bicycle rim.

Ancient Zen koan: what is the sound of one pedal scraping...

A proper ebike should have no issues in this kind of event unless the chain ring scrapes the ground. Once you add a motor and there's not some arbitrary legal definition of ebike power limits, then it's all about the machine and one that needs pedal assist (cheating in my book) wouldn't be competitive. Plus, unless it's a recumbent or semi-recumbent, any bike set up to pedal well will give up way to much to the wind a next year's speeds. Lower is better. Normal upright bikes are far more dangerous anyway...You'll never see any motorcycle with that kind of wheelbase and COG location, not even close.

 

[veloman]

OKay, you drill out the side plates on the hub motor for ventilation. Then why not add some really big heat sinks to the hub, inside the wheel? That should help a good deal too, no?

I do realize that 20% x 3000watts = 600 watts of heat to disipate, which is a lot.

 

[neptronix]

You have a good point. And i must say as a 6 footer with long legs that rides on a 21in. frame, my center of gravity is not so good since i'm up so high. And i am using longer than normal cranks too.

I don't think the people organizing or ranking the electric bike contest are going to think pedaling is cheating.... so it's imperative that the bike is still pedalable though. At the very least, pretend to

When you have little clearance between the pedal and the ground, you're going to have problems as soon as you take a substantial turn due to the angling of the bike. You can go with shorter pedals, but then your knee may not be extended far enough for a good power stroke of the legs. I already occasionally have this problem on 26" wheels with 185mm cranks when i'm trying to pretend i'm a motorcycle around a turn.

Anyway that's my opinion. Take it or leave it. I will continue to look for the perfect frame, wheel, and gearing situation.

 

[adrian_sm]

Interesting graph from another thread regarding continuous torque limits of motors.

Source: bigmoose in this thread
Original Source: http://www.evo-electric.com/inc/files/AFM-140-Spec-Sheet-V1.1.pdf