When replacing a tire purchased from an Internet retailer, bead removal is the first hurdle if it is a tubeless tire. Conversely, as long as the bead is down, you feel as if you have won. However, the bead may rise unnoticed when installing a new tire, causing you to sweat profusely because you can't mount the tire. With the bead-down keeper, tire assembly becomes much easier, regardless of whether you are installing tubeless or tube tires.
When removing an old tire, it is important to drop the entire bead into the rim.
Buying tires at a motorcycle supply store and having them replaced is a sure-fire way to get tires done. With the recent popularity of motorcycles, it is difficult to visit a store on a whim and have the tires replaced on the spot. If you cannot make an appointment for work on your day off, you can buy tires online and replace them as a DIY project. Of course, this requires a work space and adequate tools.
Bead removal is an essential part of removing tubeless tires. It can be done by stepping on it with your foot, hitting it with a hammer, or placing it between the workbench and the ground and clamping it with a pantograph jack, but the most reliable method is to utilize a bead breaker.
Once the bead breaker is set at the border of the rim and sidewall, the key is to push it straight down (toward the center of the rim). If the tip of the plate only goes in at an angle, the bead will have a hard time getting over the hump and will easily scratch the inside of the rim.
Everyone knows that a tube tire is a tire with a tube inside and a tubeless tire is one without.
Tubular tires maintain its shape with air inside the tube, while tubeless tires maintain its shape in direct contact with the rim. (Wheels with humps are also available for tube tires).
For this reason, when air is removed from the air valve during a tire change, the bead of a tube tire easily drops into the rim, whereas the bead of a tubeless tire remains on the outer edge of the rim. Therefore, when replacing a tire, it is necessary to drop the bead over the protruding hump and drive it into the inside of the rim.
The inside diameter of the bead is constant, but if the bead falls over a hump to the inside of the rim, its apparent diameter increases, making it easier to come off the outer edge of the rim. By holding down the bead that has fallen off the hump and using the rim protector and tire lever to flip up the bead, the tire can be removed without using unnecessary force.
A bead breaker is the best way to drop the bead, but some fierce workers use a combination of a workbench or column and an automotive pantograph jack. The pantograph jack is used in place of a press to hold one side of the rim in place and apply pressure near the bead on the other side.
When working in this manner, it is important that the other side, which is held down by the jack, be supported by the rim. If the jack is pushing the bead and the other side is also supported by the sidewall, the tire will only be deformed and no force will be applied to drop the bead. When working with tools other than the bead breaker, it is also important to take care not to damage the rim or disc rotor by getting too absorbed in pushing the bead.
Another technique is to stand at the boundary between the rim and the bead and apply weight to drop the bead. This technique may be effective for tires with narrow tread widths and high sidewalls, but often does not work for wide, flat tires.
- Point 1: When removing a tubeless tire, it is important to push in the sidewall so that the bead falls off the hump on the inside of the rim.
The bead on a new tire starts to rise on its own about halfway up.
When assembling a new tire, bead wax should be applied to both the bead and the rim. Applying a small amount of bead wax not only to the front side of the bead, but also to the back side of the bead, improves the glide of the contact area with the rim and makes it easier to assemble the tire. Soap or silicone spray may be used as a substitute, but it is better to use a dedicated product because you never know how it will affect the rim and tire in the long run.
When integrating a new tire, it is important to drop the bead into the rim for as long as possible. Dropping the bead in the center of the rim increases the apparent bead diameter and makes it easier to overcome the outer edge of the rim.
As when removing an old tire, the bead is kept down by stepping on the part of the tire that is stuck to the wheel with a knee or a shin, as when removing an old tire. The rubber itself is flexible, but the steel and nylon cords at the bead are rigid and try to maintain a perfect circle, so even if you try to push one side in with your foot, the other side will move into position on the rim by prying with the tire lever.
By moving outward from inside the rim, the diameter of the bead portion becomes relatively smaller, and the force required to get it over the outer edge of the rim is also greater. If all of the previously fitted bead is within the hump, no amount of prying with the tire lever will allow the entire bead to pass over the outer edge of the rim. If it could, the tire would easily come off the wheel.
Some people may think that a tire changer can be used even if it is impossible to do by hand. However, if you observe the process of mounting a tire using a tire changer, the sidewall of the tire that first fits on the wheel is pushed down by the arm, i.e., the bead is rotated without being placed on the hump.
Incidentally, although the bead tries to rise to the outside of the rim, the same is true for tube tires, but since there is no hump on the wheel side, it is relatively easy to drop the bead into the rim. Conversely, if a tube tire has a hump on the wheel, the bead must be dropped firmly.
- Point 1: When mounting the tire, push the bead into the center of the rim and use a larger apparent bead inner diameter to overcome the rim.
Bead-down keeper to hold the bead-down to prevent it from going up.
In this image, the bead portion is just pushed outward, but as the portion that fits into the rim increases, it is gradually maintained in a state of falling into the center portion.
Without the bead-down keeper, the operator proceeds by pushing in the first-fitted part, and the position of the tire lever gradually moves away from him. On the other hand, with the bead-down keeper, the operator can handle the tire lever at a position close to his own at all times because he is in charge of holding the bead.
The bead-down keeper holds down the bead that is going up before you know it, even though you think you are stepping on it with your foot.
When the clip-like part is set on the rim, the warped knob part simply holds the sidewall down, but the bead does not fit over the hump because of the obstruction between the rim and the bead.
Bead-down keepers are sometimes sold in single units, but if you have at least two, preferably three or four, you can set the keepers each time you fit a tire to the rim, keeping the bead-down at all times.
There is a technique of inserting a rubber hose between the rim and bead to prevent the bead from coming up, but it is troublesome to retrieve it if it gets stuck in the bead or dropped inside the tire. You may be able to insert something like a wedge, but since there are convenient tools available, it is better to make use of them.
Riders who have the opportunity to do DIY tire changes are advised to prepare bead-down keepers along with tire levers and rim protectors.
- Point 1: Setting the bead-down keeper on the rim prevents the bead from rising on the rim in the area where the wheel is assembled, allowing easy assembly without stepping on the wheel with the foot.