Which drive train gives the optimum performance (freewheel sprocket, IGH or cassette)?

[azad]

Hi,

I have been using freewheel 7-sprocket for many years. It is only recently that I've encountered IGH and was shocked to see how horrible its performance was in comparison to a freewheel hub. The drag was very real and could be felt easily. I could rotate the freewheel sprockets of the wheel easily with my hand but in order to do the same with the IGH required considerably large amount of force. Although my freewheel is a quite old (3-4 years) but I regularly grease it and clean at least teeth and chain. The experience was so bad that I had to ditch the newly bought wheel with IGH and continued using the old one with freewheel sprocket.

So, I thought this might be good discussion starter. If IGH are so bad then why are they so popular? Is there any better alternative to freewheel hub or has the technology not advanced at all for more than 100 years?

 

[john61ct]

Other IGH models may not have as much drag.

A little drag may not be important to others, not even show up on their radar in evaluating their standards of "performance".

Especially when a motor is doing most of the work, see the Grin videos / articles on "virtual electric feewheeling"

https://www.ebikes.ca/product-info/gmac.html

 

[99t4]

What do you mean exactly by "optimum performance?" Optimum performance in muddy conditions may favor the IGH. Optimum performance on the velodrome track may favor a fixie. Does maintenance frequency/cost figure into Optimum performance? Is Optimum performance the same for a time trialer and a commuter?

 

[azad]

What do you mean exactly by "optimum performance?" Optimum performance in muddy conditions may favor the IGH. Optimum performance on the velodrome track may favor a fixie. Does maintenance frequency/cost figure into Optimum performance? Is Optimum performance the same for a time trialer and a commuter?

Well even if there is electrical power there, it is still scarce resource atleast until we figure out the battery problem. In addition to that, ebikes are expected to be peddled when battery runs out. This means that ebike should not be more draggy than a typical bicycle. I am not sure about the exact numbers but somebody pointed out in another thread that one loses about 22watts of power per 200watts which would translate to more than 100watts per 1000w which is a significant power loss and range of an ebike.

 

[Balmorhea]

Keep in mind that when you turn the sprocket on an internal gear hub, it's like turning all the sprockets, pulleys, and chain in your derailleur system, not just the freewheel.

Gearhubs are measured to be less efficient than clean, well aligned derailleur gears, but their relative efficiency increases with load. Yours might be grossly overtightened or otherwise not running correctly. And not all gearhubs are in the same category with regard to efficiency.

When I used a NuVinci hub or a Shimano Nexus 7, I could feel the drag relative to a derailleur geared bike. But with my Rohloff Speedhub, SRAM Automatix, or Sturmey Archer RX-RK5, I don't really notice extra drag. They feel a little different at the pedals, and they make different noises. But they don't seem slower enough that I notice that.

 

[99t4]

Maybe you are asking about which is most efficient?

...ebikes are expected to be peddled when battery runs out. This means that ebike should not be more draggy than a typical bicycle.

Typical bicycle? On a typical day I see typical bicycles with freewheel, cassette, IGH, fixie, 1-speed w/ freehub, single, double, triple crank, they all are pretty typical. Some have electric dd hub motors, geared hub motors, mid-drive, MOST are factory built, a few are custom built. A lot are fatbikes. To me the worst to pedal w/o electric power would be the fatbike. A dd hub is pretty efficient, but not so enjoyable to pedal w/o electric assist. If you are down on IGH because of minor efficiency losses, remember the worst part of pedaling an e-bike w/o assist is the extra weight. On starts and hills is where you feel it the most.

The key is to not run the battery out. Plan your route according to your battery capacity. Cut your speeds as necessary. Take the charger if feasible. If you are running out of battery too often, get a bigger/better battery.

I am not sure about the exact numbers but somebody pointed out in another thread that one loses about 22watts of power per 200watts which would translate to more than 100watts per 1000w which is a significant power loss and range of an ebike.

You're saying IGH suffers 11% loss in efficiency?

 

[azad]

Maybe you are asking about which is most efficient?

Yes! and I'm surprised to know that IGH is so inefficient considering that it is covered from dust and all.

Typical bicycle? On a typical day I see typical bicycles with freewheel, cassette, IGH, fixie, 1-speed w/ freehub, single, double, triple crank, they all are pretty typical.

By typical I meant a well maintained geard bicycle which one would want to ride regardless of electricity.

If you are down on IGH because of minor efficiency losses, remember the worst part of pedaling an e-bike w/o assist is the extra weight. On starts and hills is where you feel it the most.

Yes but that weight can be pulled if one has lower gear on the bicycle which is really low without the drag but what I have realised is that even the lower gear in IGH has a strange resistance as if metal parts are rubbing against each other without any rolling mechanism (e.g. balls or bearing).

You're saying IGH suffers 11% loss in efficiency?

Yes!

 

[wineboyrider]

Hi,

I have been using freewheel 7-sprocket for many years. It is only recently that I've encountered IGH and was shocked to see how horrible its performance was in comparison to a freewheel hub. The drag was very real and could be felt easily. I could rotate the freewheel sprockets of the wheel easily with my hand but in order to do the same with the IGH required considerably large amount of force. Although my freewheel is a quite old (3-4 years) but I regularly grease it and clean at least teeth and chain. The experience was so bad that I had to ditch the newly bought wheel with IGH and continued using the old one with freewheel sprocket.

So, I thought this might be good discussion starter. If IGH are so bad then why are they so popular? Is there any better alternative to freewheel hub or has the technology not advanced at all for more than 100 years?

They are popular, because you just admitted that you like to maintain your freewheel? Some of us would rather have a low maintenance setup and ride more. In fact, I want a small front hub ebike and a 3 speed igh rear as an ideal commute around town setup.