Just a thought Nuvinchi hubs

If you read NuVinci's whitepaper on use for electric vehicles, I seriously doubt you have a real loss there. Increased top speed, increased range, increased hill-climbing ability, increased acceleration...doesn't sound like a loss to me.

http://www.fallbrooktech.com/LEV-CVT_Whitepaper.pdf

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http://www.jasonhight.net/videos/mot...etowork-sm.wmv

Yes, I have seen the Fallbrook tech literature but considering it comes from their internal engineering dept. I would hardly expect anything different.
That's why I asked about either anecdotal or better yet empirical evidence. The Ebike
site I linked is one of the few conversations on this I've encountered.
On another motored bike forum, a well informed user when asked about the NV confirmed a fairly substantial power loss, in his estimate 25%. He seemed content to live with that however,
explaining his setup is primarily useful in low end torque in the off road riding he does and he
is running a fairly powerful motor.

I have a hard time believing there is any power loss in the minutest. Sombody here knows the truth! Clotho I think was the name he has one and would have mentioned such a hainus malfunction! Simply just not true Bearings are bearings gears are gears. NOT BUYING THIS STORY FOR A SECOND . They made this for many app like windmills to gen electricity. NO WAY

There is always going to be a power loss in any type of gearing/transmission. You would measure this by strapping the motor to a dyno and get an hp reading. Then strap the bike with transmission to a dyno and get another hp reading. Then you can see the power lost. This is why cars are generally rated with hp of the motor, not at the wheels.

But 25% seems way too high.

So yes, there will be some power loss, but it ends up being a net gain in usability since you can go further faster for longer.

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http://www.jasonhight.net/videos/mot...etowork-sm.wmv

Absolutely noway its 30 percent loss! Nobody would want it, there would also be a ton of complaints. We all here cry about mufflers and carb to much here.

THE OLDER 4 WHEEL ATV, THE BANSCHEE WAS FAST. THEY USED CHAIN DRIVE TO AVOID SHAFT DRIVE (GEARS) POWER LOSS. I DO NOT KNOW HOW THIS WOULD RELATE TO NU VINCI.

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PUMP YOUR BRAKES
NEVER BEAT ON IT, GET A BIGGER HAMMER

Anytime you make a system more complicated and add more parts (ie. a transmission) to it you will likely increase friction as well. This increase in friction correlates to a decrease in efficiency.

I found this quote far down the page Here

Internal gear hubs have a efficiency of 92% compared to 98% for derailleurs. These numbers are valid for new and perfect trimmed drivetrains!

Internally geared hubs like the Shimano 3, 5, 7 speed hubs are cleaner and simpler to operate so why doesn't everyone use them? 2 reasons. They are heavier and they less efficient than a derailleur style transmission. The difference may only be 6 percent between them but for many cyclists that would be 6 percent too much.

Our application is different however and other features such as gear range and durability are also important. I have found the Nuvinci to be excellent in both categories.

The Shimano style internally geared hubs may be 92% efficient but the Nuvinci is probably even less based upon the design. If you try to find hard numbers from Fallbrook they seem to evade the question and instead tell you to ride it and see for yourself. They claim that the ease of shifting and the ability to always be in the right gear overcomes any increased loss in efficiency. They may be correct.

As an example I have 2 bikes that are very similar. Both have 70cc (true) motors with the same hp modifications right down to the same style expansion pipe. Both have street tires and are well maintained. The biggest difference between them is that one has a Nuvinci hub and the other has a conventional derailleur. The Nuvinci bike has more top end and accelerates better. Now I know this doesn't make sense because of my statement that I thought the Nuvinci is less efficient. I get that impression from when I pedal them without being under power. The derailleur bike seems to take slightly less effort. So why is the Nuvinci bike faster? Perhaps Fallbrook is right and being able to always be in the right gear and smooth shifting counteracts any loss in efficiency. It is hard to tell but one thing I am certain about. If you are going to put a gas motor on a bike the decreased efficiency of the Nuvinci hub is more than made up for by all its other qualities.

Thanx for the input Clotho been thinking about this hub allot lately. I think I will get one .

Good stuff. It's great to see some actual side-by-side experience cited as empirical evidence.

How are you transferring power from the engine to the rear wheel on the two bikes, left side drive sprockets or a jackshaft to the drive train?

Reading through the comments on the hub blog you linked I thought this was interesting also:

I agree that is interesting.

Both bikes use a Sick Bike Parts shift kit.