Frequently at TiendaMTB.com we receive inquiries about how oval chainrings work, if they are really noticed or if they have any contraindications. In this article I give you my point of view, since I have been using a 32 oval Leonardi chainring for almost two years, combining it with a bicycle with a round chainring.

Let's start with the theory: By how we sit and how the cranks rotate, the point where we can make more strength is when the cranks are horizontal. On the other hand, when the cranks are in the most vertical position, our legs can not press down, but they have to move the foot forward to go to the point of strength. This movement of moving the foot forward involves muscles that are less strong than those that act with the cranks horizontally. Also at that time the knee is quite bent, so that all that force "crushes" the knee, generating great pressure on it.

The oval chainrings improve performance and take better advantage of the force because they minimize the dead point when the cranks are vertical. That is, when the cranks are vertical, the chainring has fewer teeth. In this way, although the muscles that act at that moment are weaker, they can advance the crank due to the lower gear ratio. By needing less force to advance at that point, the load on the knee is also less.

The equivalence of an oval Leonardi chainring with round chainrings is -4 teeth in the short zone and +2 in the long zone. For example, a 32 teeth oval Leonardi Gecko Track equals a round plate of 34-28 teeth depending on the pedaling point. This results in more uniform pedaling and less pressure on the knee in the dead point.

That is why they are highly recommended for people with knee problems. Also, no difference in pedaling on flat or downhill. Simply that climbing hard ramps are easier, because the leg always goes to the point of force (horizontal), and you do not get stuck with your foot up without being able to force and have to step foot to earth. You can even start from standstill (after stopping to get some air) in the middle of a wall of those that is one in the firewall (I tell you from experience).

It is true that people who have competed for many years have that knee muscle very developed, and a very precise coordination of pedaling, and changing it in the middle of the season, will surely lead them to partially waste the force they can generate and that so many workouts has cost. For them I recommend making the change once the season is over. What is clear is that oval chainrings work, and they are not a rare thing. There we have Chris Froome (among others) winning Tours of France with them. I recommend them.

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