Electric bike hub

[AndrewJ]

Originally Posted by Lazarus

It just a standard 18 speed road bike made by Iron Horse.

Ok, thats at least a good starting point, I was sure it had to be a road bike by the 17mph average speed, but hey, who knows, you could have been Lance Armstrong on a DH bike or something.

Anyway, if you're trying to get faster, keep in mind that the aerodynamics of bikes is a bit different than cars. Namely, the "tipping point" where aerodynamics become an important factor is around 20mph (or so I have heard from multiple sources)
It seems that once you pass 20mph on a bike, over 50% of your energy is going to combat aerodynamic drag, and it just goes up from there. I think the source for that tidbit is the League of American Bicyclists' "Road I" course, but I could be wrong.

So, the key to making a battery last longer might be aeromodding your bike. Look into time trial stuff for your bike. Most of it is expensive, and somewhat heavy, but an aerobar wouldn't cost much, and getting into a more aerodynamic tuck would be hugely helpful.

[SVOboy]

Originally Posted by MetroMPG

That would be the way of the ForkenSwift, yes. (Minus the last step about getting better ones.)

A tip that might solve the expense problem: I know a guy who services security & fire alarms. He can pretty much keep me in as many used 12v 7AH SLA batteries as I can take. I've actually been using them (a couple in parallel) in the ForkenSwift for accessory power.

These are automatically replaced when they don't meet the company's 80% performance criteria.

Might be worth dropping by a local security alarm business or making a few calls.

You (or someone else in the know) should post up sometime on various sources of free batts and things that might be useful to people (like the vw solar panels), you know?

[Lazarus]

Originally Posted by AndrewJ

Ok, thats at least a good starting point, I was sure it had to be a road bike by the 17mph average speed, but hey, who knows, you could have been Lance Armstrong on a DH bike or something.

Anyway, if you're trying to get faster, keep in mind that the aerodynamics of bikes is a bit different than cars. Namely, the "tipping point" where aerodynamics become an important factor is around 20mph (or so I have heard from multiple sources)
It seems that once you pass 20mph on a bike, over 50% of your energy is going to combat aerodynamic drag, and it just goes up from there. I think the source for that tidbit is the League of American Bicyclists' "Road I" course, but I could be wrong.

So, the key to making a battery last longer might be aeromodding your bike. Look into time trial stuff for your bike. Most of it is expensive, and somewhat heavy, but an aerobar wouldn't cost much, and getting into a more aerodynamic tuck would be hugely helpful.

Good points. I've tried the aero bars and it a little to dangerous for city commuting. Quick access to brakes is a common reality, also control and visibility are a little marginal when dealing with cars and road debris. I've thought about a fairing of some sort like a motorcycle but I think the increase in drag would offset the aero benefits for a standard bicycle.

[MetroMPG]

Re: in-town riding... Do I take it a 'bent is out of the question then? Do bents not offer more efficiency?

[AndrewJ]

Depends on the hillyness factor. 'Bents are better in the flat stuff because of the better aero. On the hills they suffer because the riders seating arrangement isn't ideal for powering up a hill.
On a "normal" bike the rider can use gravity (their own body weight) to assist them in climbing by standing up on the pedals.

As with everything, what you're dealing with here is tradeoffs. If you're looking to go faster up the hills you'll need something completely different than if you're looking to bomb down the flats faster.

[MetroMPG]

So it would seem to me then that an e-assisted bent would be the best combination of compromises...

[AndrewJ]

Originally Posted by Lazarus

Good points. I've tried the aero bars and it a little to dangerous for city commuting. Quick access to brakes is a common reality

Have you thought then about full on TT bars?


for commuting I would switch the placement of the shifters and the brake levers, and add cyclocross-style "interruptor" levers on the straight part of the bullhorn bars.


That way you have one set of brake levers for each hand position.

[Lazarus]

Interesting idea with the brakes.

No bent here. I don't want to start a which is better debate but I prefer a road bike. I have a lot of rolling terrain and I like the hight, visibility and maneuverability of a road bike.

[MetroMPG]

Them's fightin' words!

Just kidding.

[Christopher Jordan]

Originally Posted by AndrewJ

Depends on the hillyness factor. 'Bents are better in the flat stuff because of the better aero. On the hills they suffer because the riders seating arrangement isn't ideal for powering up a hill.

Kind of a myth since that depends on the engine. Some are slow, some aren't: same as 1920 diamond frame bikes. But anyway; in this thread the engine is a combination of human power *and* a hub motor, is it not?

Excellent addition! I had an Electric Sierra Cycles 36 V hub motor installed in my fully enclosed recumbent trike, and hills are no problem at all!

countersTrike <---------------