Bicycle aerodynamics is a systematic project involving many means, not just bicycles. Accessories such as kettles and helmets have a considerable impact on aerodynamics.
The kettle is a very insignificant equipment, but its wind resistance can not be ignored. When the speed reaches 40km / h, the resistance generated by the kettle can reach 56g and the power consumed is about 5.6watts (cerv é Lo's data). For a better amateur athlete, the 40km timing is calculated according to the power of 230watts, so the improperly placed kettle will lose about 2.4% of his power. 40 km is completed in 60 minutes, and 2.4% of 60 minutes is 1.44 minutes. Is this 1.44 minutes very tempting?
Cooper Perkins conducted a wind experiment under the condition of 48km / h. The results show that the kettle is the second factor to improve the performance, and it is basically the best cost-effective means (the experimental results are converted to 40km / h, which is basically equivalent to the test results of cerv é Lo on the kettle)
Then let's take a look at how to place the kettle on the triathlon bicycle to achieve the best aerodynamic effect, as well as the advantages and disadvantages of other aspects.
Place an ordinary kettle behind the saddle
The resistance is equal to 0. This is a very good placement method with no negative impact on aerodynamics. You can also carry spare inner tubes, folding tires, tire prying rods, gas cylinders and other items in the kettle.
Cerv é Lo's experimental results show that placing a kettle behind the saddle is even better than not. From the simulation, there is a low-pressure area (cold area) behind the driver, which can be filled by placing a kettle.
When placing the kettle, it should be noted that the kettle should not appear outside the front projection of your torso, otherwise it will cause the problem of driving. The kettles should be as close to each other as possible and close to the trunk, otherwise the lateral wind will cause resistance to the kettles.
This placement has some defects in ergonomics: it is difficult to turn back and take the kettle in TT riding posture. It is better to use the kettle behind the saddle as a reserve kettle. When using, move the beverage or the whole kettle to a convenient place.
In addition, the driver can't see the state of the kettle support during the race, so the installation needs to be firm and firm to prevent the kettle from bouncing out or even the whole support from falling off when it is bumpy.
The air breaking kettle and kettle rack of aerodynamic design are placed in the conventional position (on the lower pipe or riser)
The resistance generated by this placement method is related to the frame. Generally, it is about 20-25g, which is about half lower than that of an ordinary kettle.
The disadvantage is that the price is higher than the conventional kettle. In addition, it is more troublesome to replace the kettle during the competition. After all, it is not a standard size.
As for whether it is placed on the riser or under the pipe, the resistance is smaller. The wind experiment shows that it is related to the specific frame.
The ordinary kettle is placed horizontally in the middle of the rest handle
Resistance less than 0! It fills the gap between the forearms, so it's better to put the kettle in this position than nothing. In other words, it is faster to put the kettle in (the conclusion comes from cerv é LO).
But the premise is that it must be placed between the two arms. It can't be higher or lower.
The operation of ordinary kettle is troublesome, and the capacity of beverage that can be carried is a limit. There is also an improved kettle with water pipe. Although this kettle is convenient to drink water, the water pipe brings certain wind resistance.
The aerodynamic kettle is placed vertically in the middle of the rest handle
There is a certain resistance in this way. The resistance is smaller than that of an ordinary kettle on the frame. The specific size is related to the shape of the kettle and the size of the head pipe. In addition, the wind resistance generated by the vertical straw is a deficiency.
Ordinary round kettle placed in standard way
This is the most common way to place the kettle, and the wind resistance is also the largest. The resistance is about 40-50g. The utility model has the advantages of convenient and skilled operation and easy replacement.
The installation is different at different positions of the frame, and the wind resistance of lower pipe installation is smaller than that of riser installation.
The following figure is the best place to place the kettle. The kettle does not generate additional resistance at these two positions. If it is placed reasonably, it can even reduce the wind resistance of the whole vehicle, which is equivalent to obtaining additional power.
Finally, when installing a kettle in a new location, you must practice more, find the most skilled and convenient way, and avoid using new equipment on the day of the competition.
