How to True a Bike Wheel
When an unlucky cyclist hits a large stone or wall, the rim on the wheel is bent, and it becomes almost impossible to continue. What to do, and how truing a bike wheel works?
If the wheel rim does not crack, the situation is not desperate, but quite repairable. You just need to straighten this rim. Okay, but how to do it? In this article, we will tell you about trueing bicycle wheels.
Tacoed bicycle wheel truing
To begin with, let’s find out what kind of damage we have to deal with. The types of curvatures that can be corrected:
- A small “taco” where the curvature of the wheel rim is limited within a section between two or three spokes.
- A large “tacos” where the wheel rim is curved between five and seven spokes or more.
- “Egg” when the rim lost its round shape and became more oval.
There are at least three ways of straightening bike rim
- The emergency method, using no wheel truing tool with the physical force of the bicycle’s arms and legs. It is usually used in case of an accident on the way, only to get to a place where a more thorough repair is possible. In this way, you are unlikely to achieve great accuracy. Only the strongest curvatures that prevent the uniform rotation of the bicycle wheel are eliminated in this way. Left fineer residual curvatures for later.
- Bicycle spoke adjustment. This method can show quite accurate results if you have enough skill and luck. But it is very time consuming and requires patience and diligence from the cyclist.
- A mechanized way, using the rails or machines. This method gives the best results in quality and precision. The only problem is that not every rider has the right rack or machine at his disposal. If you don’t have the skill, desire, and patience to straighten the wheel rim yourself by hand, you should give it to a specialized cycling workshop, where you will find such a machine.
If you are in an emergency that has led to such a strong deformation of the bicycle wheel that it is impossible to continue moving further, follow the proposed procedure. It is always better to put the emergency bike in the trunk of the car, but if you do not have this option, then:
- Put the bike upside down – on the handlebar and saddle.
- Remove the tacoed wheel from the bike. There is no need to remove the camera with the tire – in this case, you can correct the bicycle wheel with them.
- Determine the place of the greatest curvature. In such grave cases, it is usually obvious.
- Use your knee as a fulcrum and hands as levers. Put your knee at the top of the arc of curvature, grab it with your hands at the base of the arc, and try to gradually level the rim with your hands. Do not overdo it in order not to bend it in the opposite direction.
- Put the wheel back on the bike. Try to spin it. If it rotates freely and does not rub against the fork (front) or frame (rear), you can sit on it and continue riding to the nearest repair site. If it still rubs, remove it back and repeat the “knee-handed” correction operation.
Adjusting the rim by tightening bike spokes
This method is valuable because it is possible to correct both large and small curvatures (“tacos”) of the wheel rim while achieving very high accuracy. But in fact, it is quite a torturous case, which requires a lot of patience even from an advanced cyclist (cyclist mechanic).
In general, the method is a combination of loosening and tightening bicycle spokes. In this method, numerous tests and modifications are inevitable.
The most important initial operation is to determine the peak of the wheel rim curvature. Since we struggle with much smaller curvatures than the emergency ones, this place will not be so obvious anymore.
You will need only a piece of chalk. Turn the bike upside down, speed up the curved wheel, and gently bring a piece of chalk to the rim. When the chalk touches its surface, it marks the top of the arc.
Truing a bicycle rim with a small “taco” (the rim’s curvature is within three spokes) follow this order
- Pull the central spoke with the key by 1/4 turn.
- Loosen two spokes on the sides by 1/8 turn.
- Check the result.
When correcting a large “Taco” (rim curvature takes, for example, a segment of 7 spokes), the scheme may be as follows
- Tighten the central (4th from the beginning of the segment) spoke on 1/2 turn.
- Loosen two spokes on the sides (3rd and 5th) to 1/4 turn.
- Tighten the next two spokes in each side (2nd and 6th) to 1/8 turn.
- Loosen the remaining spokes (1st and 7th) to 1/8 turn.
- Check the result.
The procedures of adjusting bike spokes we use above are indicative, which show only the basic principle of bike rim truing: you should alternate the tightening and loosening of the spokes standing next to each other. The amplitude should be bigger at the apex of curvature, decreasing towards the base.
If the result shows that the taco is straightening, you should continue to “twist” the spokes in the same direction and ratio only by increasing the amplitude. If the curvature has only increased, you should return everything you have done to its original position, and try to change the queue of tightening and loosening of the spokes.
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