Once you've settled on your riding style with your road bike, you'll naturally become interested in gears and gear ratios.

First, let's check your bike's gears.

Then, let's consider various gear patterns.

1. Road Bike Derailleurs

As you know, road bike shifting is done using front and rear derailleurs.

The number of gears is typically 2 in the front and 8 to 11 in the rear.

These are used to select the appropriate gear ratio for the riding conditions.

It feels great when you can accelerate and decelerate with the optimal gear, but aren't there many situations where you shift gears vaguely?

Let's start by considering the gear ratio by looking at the number of teeth on each gear.

2. Road Bike Gear Ratios

If your bike has a Shimano 105 groupset, it might have the following gears:

Front gears: Large 50T, Small 34T (T = teeth, indicating the number of teeth on each gear)

Rear gears: 11-28T

The number of teeth is printed somewhere on the gear, but you can also count them manually.

If we write this out specifically, it looks like this:

The numbers with decimals are the gear ratios.

The gear ratio is the front teeth divided by the rear teeth.

Rear:      11T   12T   13T   14T   15T   17T   19T   21T   23T   25T   28T　　　

Front 50T: 4.55  4.17  3.85   3.57  3.33   2.94  2.63  2.38   2.17   2.00  1.78

Front 34T: 3.09  2.83  2.61   2.42  2.27   2.00  1.79  1.62   1.48   1.36  1.21  

The red numbers indicate the appropriate combination range for each front and rear gear.

What you should note here is that the higher the gear ratio, the harder it is to pedal.

Theoretically, if you can maintain a cadence of 80 rpm with this table, you can reach a top speed of 46 km/h with the 11T gear.

3. Close Ratio and Wide Ratio

Close ratio refers to a cassette sprocket where the gears have closely spaced teeth.

Taking the table above as an example, a close ratio is when the gear teeth increase by one from the top gear of 11T to 15T. Since the steps between gears are small, smooth shifting is possible.

From 17T onwards, the gears increase by 2 to 3 teeth, which can be considered a wide ratio. The characteristic here is that it can cover a wider range of gears.

4. Standard Gear Configurations

① Front Gears

Generally, three patterns are standard:

53T-39T This combination is called a "normal set," but it requires leg strength and body weight.

It's suitable for aggressively riding on flat terrain, like in TT races. ICAN's Aero A9 uses this gear ratio.

52T-36T This size is called "semi-compact." It's considered suitable for racing because it allows for faster times. Since there's a large difference in the number of teeth between the two gears, you need to be careful about chain drop.

50T-34T　This set is called "compact," and it's currently standard equipment on a considerable number of bikes. It can be said to be the optimal size for normal touring.

② Rear Gears

Shimano 105 offers the following standard gears:

11-28T　　11, 12, 13, 14, 15, 17, 19, 21, 23, 25, 28T

11-30T　　11, 12, 13, 14, 15, 17, 19, 21, 24, 27, 30T

11-32T　　11, 12, 13, 14, 16, 18, 20, 22, 25, 28, 32T

12-25T　　12, 13, 14, 15, 16, 17, 18, 19, 21, 23, 25T

11-34T　　11, 13, 15, 17, 19, 21, 23, 25, 27, 30, 34T

For cyclists, these are not just numbers, but data that inspires imagination, don't you agree? With the evolution of derailleurs, being able to choose a set like 11-30T, which is excellent for both high speeds and climbing, and seems almost all-purpose, is incredibly reassuring.

Some argue that the 11T at the top is unnecessary, but this is because when you gain speed on a descent, a 12T might be too light. Therefore, if you don't frequently use long descents, a set starting from 12T is fine.

For the easier climbing 11-32T and 11-34T, since the gear teeth on the top and low gears are far apart, a GS (long cage) rear derailleur needs to be used.

As an aside, are you familiar with "otome gear" or "ojōsama gear" (maiden gear, princess gear)?

The 32T and 34T rear gears mentioned above, with their conspicuously large sprocket diameters, are sometimes called this by serious riders who believe that a more compact appearance is cooler.

However, recently, there are quite a few veteran touring companions who have become "maidens," and seeing them climb hills effortlessly makes me think, "This is also a valid option." It might be especially recommended for actual maidens and older riders.

5. Crank Length

If we're talking about gears, we must also touch on crank length. The question is, how do you determine the appropriate crank length?

Typically, standard crank lengths are as follows:

165, 167.5, 170, 172.5, 175mm

It's usually determined by height, weight, and frame size. In Japan, for men's sizes, 170mm is often standard. In fact, this size is considered the easiest to use. Depending on the completed bike lineup, there are cases where all frame sizes uniformly come with 170mm, so there doesn't seem to be much need to be concerned about differences due to physique.

By the way, some people are experimenting with changing to shorter cranks.

170mm → 165mm or 170mm → 160mm seems common, but in extreme cases, there's even 143mm, and some are saying it works quite well.

Why do you think that is?

When the crank is shorter, the pedal height is lower when the pedal reaches top dead center. This means it's easier to get over the top dead center of the pedal. Specifically, it minimizes joint flexion and reduces physical strain.

Also, by reducing the radius of rotation, the rotational speed of the pedal is also reduced. As a result, a reduction in time can be expected.

Of course, there are also disadvantages, such as it not being suitable for standing (dancing), and the pedaling becoming heavier, which might require changing to lighter gears.

If you're interested and can find a test ride bike, it might be worth trying.

6. Single Front Chainring

When you looked at the gear ratio table earlier, did anything strike you as odd?

Ultimately, it's not possible to cover all 11 gears with just one front chainring. You have to cleverly combine front and rear gears to avoid chain cross-over. As you know, it's certainly not 2 x 11 = 22 speeds.

In that case, the idea of having a single front chainring and covering the range with a wide-ratio rear cassette has come up, and experiments are actually being conducted.

To accommodate the wider range of rear gears, it seems possible to prevent chain drop by using a front chainring with "Wolftooth" style taller teeth.

Since the rear gears become larger, there isn't much expectation for weight reduction. However, the cleaner appearance is an undeniable trend for casual touring.

7. Summary

The world of gears, which can be called the heart of a road bike, is profound, and it seems impossible to cover everything in a single article. I think it would be interesting to create another special feature with a different perspective.

And, as usual, allow me to say this one last line:

The ICAN brand is a friend to cyclists, and we sincerely appreciate your support!

【Reference】ICAN Products Official HP