Does a Rohloff Speedhub make you fitter? Notes about sprocket ratiochoice.

I'm probably somewhere between a masher and a spinner, and too old to
learn proper cadence control even if I wanted to. But in any event I'm
not at all certain cadence would be more advantageous to me than my
present method of controlling exertion by respiration rate.

Controlling exertion by heart rate rather than cadence works for me to
such an extent that I must be much fitter than I was even last year,
despite the fact that through this miserable winter (bring back global
warming!) I've ridden only 650km since the beginning of the year.

How do I know I'm fitter? I very carefully calculated the gearing of
my new Rohloff hub gearbox by reference to two successful Shimano
Nexus-equipped bikes. The idea was to give me three extra gears below
the Nexus to get up the steep hill before my house, and to ignore the
fact that two extra high gears on the Rohloff would be wasted. The
point of buying the Rohloff was thus not the 14 gears per se but the
spread of useful ones within the Rohloff sprocket ratio restriction of
2.375, within which I chose 38/16.

So the Nexus-equipped bike would have gear inch ratios from 27.3 to
83.8, mountain bike territory, with which I lived happily for five
years, while the Rohloff-hubbed bike would have ratios from a goats-
only low of 19.5 to a road-racer's 102.6 gear inches. The Rohloff bike
has three gears below and two above the Nexus, which doesn't add up
right: there is a ratio gap in the Nexus box between gears 4 and 5
into which the Rohloff fits an additional gear -- see the table below.

Another way of looking at it is that I chose my sprocket ratios to
match my expected speed on the flat of 20kph at my usual cadence of
60rpm in the direct 1:1 ratio which on the Rohloff is gear 11. In the
table below the Shimano Nexus ratios are arranged for nearest
correspondence with Rohloff gears.

Now I find that I'm often in the two high gears on the Rohloff that I
expected to be wasted, pulling 103 gear inches on the flat and slight
uphills. The fact that my new Rohloff bike is about 5kg lighter than
the old Nexus one simply cannot account for that much newfound speed.
When I first calculated that 103in gear, I laughed aloud; that's road
racer territory, I though, my bum in the air -- never going to happen!
My average speed has also crept up to where last night, back home from
a standard ride, I noticed my average speed was 14.8kph, where last
year for the same ride it was somewhere between 12 and 13 kph.

That's not all. I now find that the lowest gear isn't necessary for
pulling up the steep hill before my house (up which a lot of
impressive cyclists push but I ride).

As I say, i dunno if this is me getting fitter, or just using the
gears more because I have them, but I would suggest to people
considering buying a Rohloff hub that they calculate the sprocket
ratio very carefully indeed. You can't have too many low gears but
under 20in might be *too* low except for climbing walls, and a high of
103in now doesn't seem excessive even for a less than pacey cyclist.

See the table below.

Andre Jute
Visit Jute on Bicycles at
http://www.audio-talk.co.uk/fiultra/...20CYCLING.html

Comma-delimited table for reconstruction

x, x, x, x, x, x, x
x, DATA, x, x, x, x, x
x, Rohloff 14, x, x, Nexus 8, x, x
x, 38 x 16 = 2.375, Chainring/sprocket, x, 38 x 20 = 1.9, Chainring/
sprocket, x
x, 60 x 622, Tyre, Big Apple, 37 x 622, Tyre, Marathon +
x, 29.45, Circ inches, x, 27.3, Circ inch, x
x, x, x, x, x, x, x
x, COMPARISON, x, x, x, x, x
Gear number, Rohloff 14, x, x, Nexus 8, x, x
Rohloff/Nexus, Ratio, Gear inches, kph @ 60rpm, Ratio, Gear inches,
kph @ 60rpm
1/-, 0.279, 19.5, 5.6, x, x, x
2/-, 0.316, 22.1, 6.3, x, x, x
3/-, 0.360, 25.2, 7.2, x, x, x
4/1, 0.409, 28.6, 8.2, 0.527, 27.3, 7.9
5/2, 0.464, 32.5, 9.3, 0.644, 33.4, 9.6
6/3, 0.528, 36.9, 10.6, 0.748, 38.8, 11.1
7/4, 0.600, 42.0, 12.1, 0.851, 44.1, 12.7
8/-, 0.682, 47.7, 13.7, x, x, x
9/5, 0.774, 54.1, 15.6, 1.000, 51.9, 14.9
10/6, 0.881, 61.6, 17.7, 1.223, 63.4, 18.2
11/7, 1.000, 69.9, 20.1, 1.419, 73.6, 21.1
12/8, 1.135, 79.4, 22.8, 1.615, 83.8, 24.1
13/-, 1.292, 90.4, 26.0, x, x, x
14/-, 1.467, 102.6, 29.5, x, x, x
x, x, x, x, x, x, x