Wednesday, November 20, 2013

Internal Gear Hub Revisited

I have been riding, on and off, the 4-speed bike that I put together about 3 months ago using the Shimano Inter-4 4-speed internal gear hub. Generally, I like it quite a bit, but at times, the gear ratio leaves me wanting. I know this sounds strange coming from a guy who rides a single speed bike most of the time, but when you are on a single speed bike, you don't think about shifting, and riding a bike with gear shifter, it's a different mindset.  

The Good:
"Silent" shifting
Simple and low maintenance
Gear ratio is good enough for most situations

The Bad:
More drag than normal wheel
Noisy when coasting
Trigger shifter sucks (er, sticks)
Coaster Brake is a real drag; engages far too easily
A nightmare to change a flat tire

As you can see, there are more bads than good.  So I have been looking for an alternative. Came across a very cheap, decades old Sturmey Archer 3-speed gear hub; installed it, works great, and less heavy than the Shimano 4-speed, and lower drag too.  Again, coasting is noisy, and even less gear ratio than the Shimano, and the trigger shifter was not designed for flat handlebar. I was able to make it work, but it's not elegant. More searching...

"New" 8-Speed Bike - Sony NEX-6 & Super Takumar 105mm f2.8. Click for larger.

Enter the Shimano Nexus 8-speed Red Band. Like the Canon L lenses, this one came with a red band around it to differentiate itself from the normal Nexus 8-speed; it's a premium line, but below the top of the line Alfine hubs.  The hub, unfortunately, came with a wheel that's not the right size for me, not to mention the weird and uncommon 24 spoke holes.  Took me a little while to find the rim with 24-spokes, but I really prefer a double-walled rim.  Oh well, didn't want to wait so I laced it up.  This is the 4th wheel I have laced, but still can't master the skills of truing it longitudinally. I find it very hard to make the wheel round; a problem compounded by the lack of a wheel truing station.

Anyways, as imperfect as the wheel is, I mounted it on a more sturdy MASI single speed steel frame with horizontal dropout.  I had to get the yellow non-turn washer as the original was grey, for a slanted angle dropout.  It was not easy to find locally.

Shimano Nexus Red Band 8-Speed shifter - NEX-6 & Super Takumar 105mm f2.8. Click for larger.

Since I have decided to build a new commuter bike, and winter is coming, I was more careful about the components used. For the chain, I used a heavy gauge and heavy duty YBN-MK918 BMX/single speed chain.  I have been using this chain for a few years now and it's bomb proof, but more noisy than the SRAM PC-1 chain that I also use.  The cranks are Sugino VP with a 50t chainring. The front wheel is a Shimano with a DH-2N71 dynamo hub. The dynamo hub will eliminate the need to worry about batteries for the light. Front light uses a very bright single LED and I can turn it off if I don't need it on.  I had one light that had no switch, and used the halogen bulb and it wasn't bright enough and uses much more power and thus creates more drag for the dynamo hub.  LED dynamo lights used to be very hard to find, but now they are relatively common.  A search on eBay will give you lots of choices.

Shimano Dynamo Hub - NEX-6 & Super Takumar 105mm f2.8. Click for larger.

Still looking for an LED rear light that can be powered by the dynamo; there are lots of choices too, but I will decide after I get a bike rack and pannier. The rack has to provide mounting provision for a rear light. Unfortunately, the frame was not designed to take bike racks and fenders; an adapter needs to be made so that I can mount the rack on the hub axle.

The bike, even with a front dynamo hub engaged, runs smoother and less drag than the bike with the 4-speed hub.  In fact, this setup feels like riding a conventional derailleur bike, and I am very happy about.  The weight of the dynamo hub in the front balances the weight of the gear hub at the back, and the bike doesn't feel rear heavy and the overall weight is very manageable.

So far, my observations of the Nexus 8 hub:

The Good:
Very quiet shifting and coasting; almost like a normal wheel
very low drag
Adequate gear ratios (until I get hold of an 11 or 14 speed hub, haha)
Lighter than the Inter-4 4-speed hub and provides more gears

The Bad:
Expensive - ok this is relative. If you consider a good derailleur group set, the cost could be more.
Still more drag than a derailleur system
Gear shifter only comes with flat bar option; if you like drop bars, you will have to buy a third party shifter

Hopefully, this bike will get me through winter without giving me any troubles.


  1. One more good point for the Nexus range is that rear wheel changes are a peach! To disconnect my changer cable is 15 seconds. Takes longer to put a chain back on the sprocket ... can't speak for your specific arrangement :-)

    Thought that the drag had been discredited to truly minor differences ...

    Glad to see your still pedaling :-)

    1. You are right. Still, not as easy as removing a single speed wheel :)

      I pedal all year round!

    2. nothing beats a single speed "fixie" for simplicity. I was (mistakenly) thinking you were thinking of comparisons to geared bikes with "derailleur" systems. I always seem to manage to get my chain in a knot when replacing wheels with them (especially when wearing a nice shirt!).

  2. I also like the shifting when stopped. I don't like the backpedal brakes.

    1. How could I have missed that! That's one of the best features of the internal gear hub.

  3. oh, and yesterday my gear changer was frozen solid (water in the cable as well as my front brake cable) ... so that's something else in the favor of a single speed bike (in winter).

    1. This will happen here pretty soon, but I think Finland might be a tad colder than Toronto :) The worse thing is the frozen lock. Might be a good idea to have a can of de-icer in the bag, just in case!

  4. Hi, did you have to re-space the Nexus hub to fit on the 120mm dropouts?

    1. Hi Hank, luckily no. It's a bit tight, but not enough to worry about, so I just left it alone.