We recently had a flat-changing clinic during one of our team meetings. After an initial demonstration, the kids tackled the bike, changed a flat, then learned how to use CO2.
If you’re on the Eastlake team and are not proficient changing a flat or using CO2, please talk to one of your coaches, and take advantage of the opportunity to learn when there’s no pressure, you’re not in the middle of a race, or on a trail ride minutes before dusk. Everyone who rides should learn how to change a flat!
Here are some Frequently Asked Questions about Changing a Flat:
Do I need to take the whole tire off?
No. You only need to take one side of the tire off so that you can remove and replace the tube.
Facilitates finding the thing that made you flat.
Removing the tire entirely will make it easier to find the glass, thorn, piece of wire, etc. Sometimes the object will remain in the rubber of the tire, slightly poking through the inside, just waiting to flat your new tube. With the tire removed, you can practically turn it inside-out.
Takes a bit longer to remount the tire. Possibility of remounting it in the wrong direction.
a) pay close attention to decals and logos when you removed the tire, i.e., logos match up to the cassette /skewer nut side or the skewer lever side, or
b) know how to read the directional tread of a tire. Here’s the practical physics lesson of the day: Look at the tire from the point of view of the handlebar. The “V” in the tread should point away from you, with the point of the “V” pointing forward. This allows dirt or water to be directed away from the center of the tire. If there’s no obvious “V”, look for the slope of the lugs in the knobby tread. The more sloped side should hit the ground first, and the more cliff looking side should follow. Running it the other directing will induce drag.
Example: 700 x 18-28, 48mm (road tube)
- 700 = roughly 700mm rim diameter
- 18-28 Number of mm wide the tube will comfortably inflate. If the tire is narrower than 18mm, there will be too much flabby tube inside it. If the tire is wider than 28mm, the tube will be stretched too thin.
- 48mm length of the presta valve on a road tube. Deeper rims require longer valve stems. A short valve stem inside the rim may not allow you to attach the pump to inflate it.
- 26 = 26″ diameter rim
- 1.9 – 2.125 Number of inches wide that the tube will comfortable inflate.
Yes. While it is not optimal, you can use a 26″ tube in a 29″ tire.
Road bike tires are most commonly measured in metric, mountain bike tires in inches.
- often less expensive
- harder to mount onto rims
- better for 230+ lbs riders (because the bead stays in place and won’t blow off the rim)
- adds 50-75g in rotational weight, which is fine for flat terrain, but more work in hilly terrain.
- often more expensive than wire bead
- easy to mount into rims
- fold-able (you can carry one in your back pocket if you need to)
- reduced rotational weight
Is the rim and the wheel the same thing?
No. The rim is only the hoop part with the holes in it. The wheel is made up of the rim, spokes, hub, etc.