Selecting a hub gear

The choice of hub gear is a little daunting at first glance. This page is to help you through the choices.

How many gears do I need?

... is the wrong question. The number of gears just depends on the range of gears that you need and the size of the steps between the gears. Remember that you pay for more gears in some combination of weight, size, efficiency, reliability and cost.

What range do I need?

... (or want, to impress my mates).

Where do you want to ride? How energetically do you want to ride? How strong are you? The following table gives some typical values; adjust them according to your taste.

Use	Terrain	Bottom gear/inch	Top gear/inch	Range/%
Road	Flat	60	100	177
Road, leisurely	Hilly	40	90	225
Road, strenuous	Hilly	50	110	220
Road, heavily laden	Hilly	30	90	300
Road tandem	Hilly	20	120	600
Off-road, mild	Hilly	30	90	300
Off-road, severe	Hilly	20	80	400

What step size do I need?

This is more subjective than the range requirement. Many cyclists have become used to having steps in the single-digit percentages, and think that they need them all. On the other hand, riders of fixed-gear bikes manage with just one ratio. Personally I find more than 25% uncomfortable, 20% is comforable and less than 15% is needlessly close. When riding a Rohloff I sometimes change two gears at once because I've not felt the need for a single-step change.

DualDrive

DualDrive hubs have been called the worst of both worlds, but I think they are worse than that, but I still have one on one of my bikes. Why? They have the weight of a hub gear plus some of the parts of a derailleur system; in use you have to juggle two shifters; they have the maintenance needs of a derailleur; a single chainring gives a worse chain misalignment than a normal derailleur.

In its favour, it takes a 13 tooth sprocket, and with a 36% step-up it gives a decent top gear for a small-wheeled tandem. The astute among you will have noticed that it is not recommended for tandem use, and you will invalidate any warranty, but they are used in some of Bike Friday's tandems, and Bike Friday take on the warranty implications for their customers. I've never had or heard of any problems, so it may be a risk worth taking.

Latest developments

SRAM and Shimano now both have their latest offerings on sale.

The i-motion 9 has recently becone available separately, having been available only in built-up bikes for a while. It's range and number of gears is second only to the speedhub, and at just a quarter of the price.

Shimano's Alfine 8-speed is now available in complete bikes, but as far as I an aware is not available separately. It is claimed to be highly efficient and offers a trigger shifter that, for users of dropped handlebars, eliminates the difficulty of fitting a twist-grip shifter.

Future developments

Is this carbon-fibre 9-speed from SRAM the future?

Selection flowchart

Is it for a tandem?	- Y -	Small wheels?	- Y -	Rohloff,SRAM DualDrive[1],SRAM P5 Cargo?
\|		\|
\|		N
\|		\|
N		Limited budget & for flattish terrain?	- Y -	SRAM P5 Cargo
\|		\|
\|		N
\|		\|
\|		Rohloff
\|
small wheels?	- Y -	Rohloff,SA8,anything else
\|
N
\|
Heavy load?	- Y -	SRAM P5 Cargo
N
\|
Almost anything - see the hub comparison table. Consider: Spectro 7 or Nexus 8. Newer: i-Motion9 (coaster brake only) and Alfine. It's probably best to avoid DualDrive and 3-speeds (for comfort)

Notes: [1] The use of a DualDrive hub on a tandem will invalidate it's warranty, see above.