I’m a fan of IGHs. I’ve got 2 Rohloffs, 2 Nexus 8s and an Alfine 8 in service in addition to a number of derailleur equipped bikes.
There are a lot of things to like about IGHs:
- low maintenance
- hard to break in accident or during shipping/transport
- clean looking drivetrain
- easy to use sequential gearing
- builds up into a strong dishless rear wheel
- easy to adjust shifting when needed
- IGH wheel can be shared easily between multiple bikes
- can shift when stopped [say on a steep hill]
- will work on almost any frame
There are also some things not to like about IGHs:
- internals are not field serviceable
- cost is higher than comparable quality derailleur setup
- greater power loss than derailleurs
- greater weight than derailleurs
- gear range usually lower than a 3 x 9 setup
- can’t tell what conditions internal mechanism is in without a tear down
- limited selection of stock bikes sold with IGHs so you have to replace a stock derailleur setup or build custom from frame in most cases
- drivetrain is in hub so if you have two wheel sets for a frame each needs its own IGH
- limited shifter options for drop bars
When you consider these points it becomes clear that there is no slam dunk in favour of derailleurs or IGHs. The optimal choice depends on what’s important to you.
Here are some things to consider:
- a quality derailleur drivetrain that has been setup properly shouldn’t need a lot of attention if used on paved roads – especially if it doesn’t see much rain. As you start to ride more in the rain and move onto mud, snow & sand derailleurs get messed up and need lots of love. This is where the IGH’s low maintenance can be a considerable benefit. However, for a lot of people who ride for pleasure or are fair weather commuters they won’t see a lot of benefit, in terms of maintenance, between a derailleur and an IGH, but they will have to deal with the extra weight, extra cost and power loss of the IGH.
- if you are having problems with your derailleurs and they are low end units replacing them with some middle of the road will probably solve your problems with less cost than an IGH and with less weight and power loss.
- derailleur setup are more efficient in the larger cogs of the cassette which correspond to low gears. A Rohloff is less efficient in the lower gears than the upper gears due to the way its planetary gears are setup. This means you’ll experience the most inefficiency with a Rohloff vs. a derailleur on a steep climb where a weaker rider can afford least to give up power.
- An IGH can be shifted at a stop. For a cargo bike or some recumbents this can be a real benefit since unweighting the back wheel to shift to a lower gear isn’t easy.
- An IGH rear wheel is very strong since there is little or no dish to the spokes and the resulting equal tension and wide base makes the wheel very robust. Having said that a well tensioned cassette wheel is strong enough for adult men to use mtn biking so for many applications it’s more than adequate. If you are not a clydesdale and/or you are not riding an overloaded bike, but still have wheel problems talk to an expert wheel builder – there is something wrong with your wheels.
- I use a 3 x 9 derailleur setup in a simple way. I ride in the middle ring 90% of the time and use the 9 cogs as a sequential gear box. I use the bottom 3 gears and top 3 gears 10% of the time when I need them. This is easy to do and doesn’t require a lot of thinking to get the right gear.
- The only satisfactory drop bar IGH shifter I have come across is the JTek bar end shifter for the Nexus 8 /Alfine 8 hubs. It’s a pleasure to use. JTek will be coming out with a bar end shifter for the Alfine 11, but it might be the end of 2011 before it hits the market. You can mount twist shifters and trigger shifters on or around drop bars and they work, but I have found them to be so poor to use that I won’t bother using such a setup.
Example #1 Sharon’s Cross Check
I’m going to build Sharon a Surly Cross Check using parts from her city bike. The goal is to have a more efficient ride for her since she is not a powerful rider. I considered whether or not to use the Nexus 8 IGH from her city bike or build her a custom 700c cassette wheel and use derailleurs.
I decided to use the Nexus 8:
- the main benefits of the Nexus 8 for Sharon are 1) it’s paid for 2) it’s easy to use/maintain.
- Sharon’s current commuter MTB has a cheap derailleur which needs monthly adjustment and she’d rather put a nail through her hand than learn how to tweak a derailleur [I don't blame her!]. The Nexus 8 is dead easy to adjust since you simply align two yellow marks are you are done. Plus it doesn’t need frequent adjustment – maybe twice a year.
- I am concerned that the extra weight and power loss are not ideal for Sharon since she isn’t a speed demon.
- I think Sharon will like the simple aesthetic of the IGH chainline and how quiet it is.
- for the initial build we’ll use swept back riser bars from her city bike and a twist shifter as well as the city bike’s v-brake levers – they are all paid for!
Looking forward I think when the Nexus 8 dies we’ll try a quality derailleur 1 x 9 or 2 x 9 setup:
- I have lots of derailleur parts in my spares bin so cost will be low.
- she can benefit from extra efficiency and lower weight.
- a quality derailleur [LX,XT, 105 or Ultegra] won’t need lots of maintenance or adjustment given she rides only paved roads.
- she would benefit from the aerodynamic position and multiple hand positions of a drop bar so we’ll use a bar end shifter.
- she doesn’t need an uber strong back wheel since she is light and doesn’t carry lots of cargo.
- with another few years of cycling under her belt she will figure out how to adjust a derailleur by ossmosis and it won’t be a big deal.
- we’ll need drop bar v-brake levers, but by that time her current ones will be old and it makes sense to replace them.
If I was starting from scratch I’d build her bike with drop bars and 1 x 9 derailleur setup mainly because as a weaker rider getting as much power to the road is a benefit she will realize every pedal stroke whereas the difference in maintenance is a smaller benefit realized only occasionally. The drop bar aero position is a benefit when she wants to get more aggressive and increase her sped.
Example #2 my Surly Big Dummy
My Surly Big Dummy was initially built up with a Rohloff hub and it’s a setup I continue to ride today. If I was starting again I’d use the same hub:
- having an uber strong rear wheel on the Dummy is critical.
- this is a heavy bike so the incremental weight of the IGH isn’t a big penalty.
- I use wide stiff tires [Marathon XRs] on this bike which cause a bigger performance hit than the Rohloff.
- I generally ride this bike short distances at moderate speeds.
- A lot of the folks I ride with regularly are weaker riders than me so the Dummy helps equalize things while being very useful if we run errands on the ride.
- being able to shift while stopped is a big benefit when you stop in a high gear at the bottom of a hill and you have a passenger on the back.
- I wanted to use Titec H-bars for this bike which work fine with the Rohloff twist shifter.
- I have used this bike for dirt road/muddy road tours and the Rohloff’s imperiousness to mud was a major benefit.
Besides being a cargo bike this bike is my dirt road/expedition touring rig. The Rohloff’s strength and low maintenance are benefits in this role that out weigh the weight and power loss. I would not ride this bike across Canada on paved roads – it would be painful compared to my Surly LHT.
Example #3 my Surly Long Haul Trucker
I built up this touring bike from parts using a 3 x 9 derailleur setup. After several thousands of kms of touring and errand riding I’m on the same cassette/chainrings/derailleurs, but I have swapped in new chains as needed. I love riding this bike. If I were to start again I’d go with a similar build although I might simplify it by skipping the front derailleur and going with a 1 x 9 setup.
- all my riding has been on paved roads [wet and dry, but mostly dry].
- I haven’t had much maintenance hassle with this bike.
- I really enjoy how the Shimano bar end shifters work and love using drop bars on this bike.
- by touring standards by 32H wheels are light to medium duty yet I have had zero problems and they have not needed adjustment since built up. I attribute this to sensible component selection and the skill of an expert wheel builder who tensioned the wheels.
- this bike is fast and efficient by the standards of a touring bike and can still haul enough gear to cross the continent while camping/cooking my own meals.
I have considered using an IGH with this bike, but upon further thought it seems I have nothing to gain by that change and I would end up with a heavier less efficient bike.
Why not just fix the problem?
Many cyclists who are thinking of IGHs to get low maintenance trouble free drivetrains should take a close look at using a fixed gear bike. By doing away with gears entirely a FG bike is lighter and more efficient than a derailleur bike while also being lower maintenance and more bombproof than an IGH.
There is this myth that FGs are slow and they are hard to climb. Neither are true for even an average cyclists as long as you aren’t medically compromised and you don’t live in San Fran! For a commuter, pleasure cyclist and even for light errands a FG offers a lot of benefits.
If the lack of coasting ability freaks you out a single speed setup adds a slight bit of weight and complexity, but lets you cost on the downhills.
Naturally for some applications [cargo biking, touring, recumbents, etc..] a FG or SS may not work, but that still leaves the majority of cyclists who could use one.
Sharon has checked out a FG/SS bike and expressed interest. What I may do for her CC is get her some 700c FG/SS wheels that she can swap in to see what she thinks. If she likes them we might skip gears entirely and go simple and light which would be to her advantage in many ways.