How to choose a sprocket for long ride
Sprockets (gears on the rear side) have various variations, there is nothing to stick out.
The factors such as the leg strength of the rider are also quite influenced, but I would like to introduce how to choose my sprocket.
Know the sprocket standard
There is also a story about what is the standard, but the most common sprocket that is assembled on the road bike is 12-25 t.
The 12-25 t sprocket can be said to be for racing. It’s hard to climb a steep hill if it is a weak leg strength at maximum 25 t. At least, I need 28 t.
On the other hand, the speed at which 12 t of the top side comes out is about cadence 80 and it is approximately 42 km / h. The professional is turning with cadence 90 ~ 100, so in that case it is about 52 km / h. You can see how heavy gears are attached to the top gear on 12-25 t.
In case of long ride, choose wide ratio
In the case of long ride, it would be better to choose 11-32 t called the wide ratio.
As the merit of the wide ratio, 28t and 32t are prepared on the rear side, so you can climb easily on steep slopes. Actually, 32t is rarely used, but if you are using 28t and you have one more you can feel relieved mentally.
Also, if you set the wide ratio, the gear that you use most often (25 km to 30 km / h) will be positioned just in the middle. The burden on the chain also decreases, and worry that the chain will run out on the way is gone. On the other hand, if you set the cross ratio, the front and rear gears become crowded, which is a burden on the chain.
Although it may be contradictory to including a heavy gear of 11 tons, the commonly used gear comes to the proper position because of the wide ratio where the gear difference is large.
Originally, 11 to 13 t are heavy and do not have much opportunity to use and tend to die as a gear. It can be said that there is no difference between 12-25 t and 11 – 32 t.
The disadvantage of the wide ratio is that the difference in the number of teeth between the gear and the gear is large. In order to keep the speed constant, it is necessary to cover the difference of the gear with the cadence, so if the difference in the number of teeth is large, it will be difficult to maintain a constant cadence and a loss will be born.
However, unless it is a race that competes for speed, it is only necessary to emphasize running even if changing the pace somewhat over time, so the disadvantage is not so big.
There is also a junior sprocket. It is a sprocket with the top side being 13t and 14t, removing heavy gear so that people in the growing season do not hurt the knees.
In the 12-25 t and 11 – 32 t as explained above, the gear on the top side has become a gear almost not used, but in the case of the junior sprocket all the gears can be fully utilized.
The old junior sprocket was unsuitable for a long ride because there were only 25 tons on the rear side. On the other hand, it seems that there are up to 28 tons of sprockets recently, so you can respond to steep slopes as well.
Since junior sprocket is expensive, it is trade-off between cost and effectiveness.
Long ride, let’s use a wide ratio sprocket. You can cope with steep slopes, the frequently used gears are in the proper position, placing no burden on the chain.