What happened to the epicyclic gear box for bikes?

[ericmark]

I remember the old 4 speed, then it went to 3 speed, then to 5 speed, but now seem to be rare, the de-railing of the chain to another gear seems more popular maybe because today it is more positive than in days gone by.

However although riding my bike I will change on sprocket at a time, wife has an electric bike, and although it has a massive range on the rear cog, I found you don't need the range, the eco, normal, sports, boost is like having gears, and likely three speeds would be enough, or at least with larger cogs, once you hit around 15 MPH the assistance is so with higher rations maybe you do want them close, but not the lower ratios.

So not sure with electric assisted if the epicyclic would not be better? Thoughts please.

 

[TheDoctor]

There's plenty of hub gears about.
Sturmey-Archer are still around with 2, 3, 4, 5 and 8 speeds, Shimano do 3, 7, 8 and 11 speed hubs, and Rolhoff do the mighty (and mightily expensive!) 14 speed.
The issue with combining motors and hub gears is that the rear hub is quite a good place for the motor. Having said that, the electric Brompton combines a front motor and a 3 speed rear hub, so it's totally doable.

 

[Rickshaw Phil]

If you like it's possible to have derailleur gears and an epicyclic gearbox together: http://www.sturmey-archer.com/en/products/detail/cs-rf3-silver

I had the SRAM equivalent on my rickshaw and it worked well.

 

[TheDoctor]

I had a recumbent like that - 3 speed hub and a 7 speed cassette IIRC. @srw of this parish has it now.
My Brompton has a 3 speed hub and 2 speed cassette for 6 gears in total.

 

[TheDoctor]

I think the S/A hub gear chronology went 3 speed, then four, which was hacked to become 5, then 7 came and went, and now we have 8.
And there's been 2 speed, and 3 speed fixed a couple of times. There was a 12-speed at some point, but that wasn't S/A.
I did see a (really expensive) E-bike last week with a CVT hub gear. So yes, doable, yet somewhat uncommon.

 

[rogerzilla]

Most conventional automatic cars still use epicyclic gearboxes. It's easy to change gear with little mechanical force by locking or releasing individual elements, so they can be operated from a small hydraulic pump.

Bikes use them because of the lack of side thrust and their relative compactness.

 

[bladderhead]

The CVT hub is called Nuvinci. Schlumpf make a 2speed gearbox that fits in the BB shell. Pinion make a 18speed box that does not fit in the BB shell. For Pinion you need a frame with a non-standard shell. I think all of these are compatible with belt-drive.

 

[Pale Rider]

Strange to relate, drag from hub gears is a problem with some ebikes.

I have a Riese and Muller ebike with a Rohloff hub.

There's no doubt the range is inferior to the otherwise identical bike with derailer gears.

The problem is worse with the NuVinci hub to the point where you won't see one on a push bike because it's so draggy.

It's all a matter of arithmetic.

If you only ever want to do 25 miles, then the fact the hub bike does 35 miles and the derailer bike 40+ miles is irrelevant.

But if you are trying to do longer rides those few miles can matter.

Hours of fun (of a sort) can be had with the Bosch ebike range assistant.

https://www.bosch-ebike.com/en/service/range-assistant/

 

[ericmark]

I have to agree the drag on old SA 3 speed was poor, but they were clean, the chain was fully covered so did not get dirt on it, or get grease on you. There must have been something wrong with the SA 4 speed hub, as although fitted to dads bike and other bikes with rod brakes, by time I started with a bike some 60 years ago the 4 speed was no longer fitted. They allowed one to change gear when stopped, so thinking about it likely would not work with ebikes as it likely continues to push a little. They were epicyclic but nothing like the Wilson pre-select which was developed into the automatic car gearbox used for years, it was not brake bands and friction clutches, it was a simple dog clutch.

But wife's bike has a 9-speed Shimano Acera gearing what ever that is, and with 9 speeds when you come to a bridge for example over a railway going down the gears and up again needs some time. My non electric bike has 8 at rear and 3 at front, so for a bridge easy and quick to drop the front gear for the short time required.

The non electric has both lower and higher gears to electric assist bike, lower are needed for hill climbing and with electric you don't need such a low gear so not a problem, and with electric assistance stopping at around 16 MPH I suppose you don't need the higher gears either, but it's not the range, want both smallest and largest as they are, but one does not really need 9 gears, 5 would be ample.

 

[rogerzilla]

The drag of one epicyclic is only about 3% for a perfect tooth profile and a suitable gear ratio (the AW hub is a good example - the sun, planet and gear ring are all sensible sizes). When you start cascading epicyclics, it all adds up. A Rohloff is terrible in some gears.

 

[bladderhead]

People always say that the advantage of a hub gear is that you can change gear while stationary. What I like is the quick, accurate shifting. One gear up, one gear down. And now, not tomorrow. And I HATE double chainwheels. One bike has a Rohloff and the other has XX1 11speed cog so I can have a single chainring.

The disadvantage of hub gears is that you can't swap cassettes between wheels.