This is the first DIY feature on bicycle repair. We’re bullish on bicycles as an efficient and clean means of transportation. It isn’t as low tech as walking, but it is far better than any other mechanized mode of transportation, according to the discussion on a previous blog post.
We made a short video, which you can see here. Read on below for written instructions.
Low Tech Video – No. 1 – Replace Bicycle Tube and Tire. See more videos from the Low Technology Institute.
Remove the Wheel
I find it easier to remove the wheels when the bicycle is upside down (if you don’t have a bike stand). Flip the bike so it is resting on its seat and handlebars with the wheels up. Shift the rear gears down to the smallest gears (nearest the outside). This gives you slack in the chain and derailleur. Release the brakes. Some brakes have a lever that releases them, while others have to be pinched closed with your hands and the cable nub pulled free. Note how the brakes were released for later if this is your first time opening them up, since you’ll want to close them again later.
Now release the quick-release lever on one side of the axle (or use a wrench to loosen nuts if your bicycle doesn’t have quick release). Once open, spin the lever a few turns, until the wheel can be lifted free of the dropouts (small gaps in which the axles rest). For the rear wheel, you have to navigate the axles free of the chain.
Remove the Tread
Release the air pressure in the tire. For Schrader valves (a rubber valve stem, like an automobile tire’s valve), use a pen cap or other pointy object and push the small column inside the valve. For presta valves (all-metal valves with threads around them), unscrew the head of the valve and then depress it.
Once the air is out, rest the wheel on both of your feet, shoulder width apart with the valve stem uppermost. Begin to press down on the tread, starting at the top, and work your way down each side, building up slack in the lower part of the tire. By the time you get to the bottom, you should see a gap between the rim and the tread. Work this gap over the rims with your hands and pull the entire tread loose.
Replace the Tread and/or Tube
Make certain you have the right sized bicycle tread and tube. The important number for the tread is the diameter of the wheel, whether it is 24 in, 27 in, or 700 c. The smaller number, usually between 0.75 and 2 in or 23 and 50 mm is the diameter. Be sure your tube matches this number. Slightly inflate the tube (just the smallest bit), and seat it in the tire. I put the valve stem near the part of the tire that gives the maximum psi so that I don’t have to hunt for it each time I fill up my tires.
Many tires are directional (i.e., they should roll only one way due to various tread patterns) so look for an arrow along the tire’s sidewall that says “Rotation →” or similar; be sure to install the tire with the arrow pointing in the right direction.
Thread the valve stem through the hole in the rim and seat the tire beads (the edges of the tires that come in contact with the rim) on either side of the valve stem down within the wheel rims. Now start working the tire beads in between the rims as you move your hands down and away from the valve stems on both sides of the wheel (similar to the motion to remove the tire, above). As you approach the bottom, you might have enough give in the tire to pop the beads right over the rim and let the tires seat themselves.
If you have a new tire or tight tires, though, you’ll probably have to work to get the beads seated in the rims. Be careful not to pinch the tube between the beads and the rims. Resist the urge to use tire irons to get the bead over the rim, but I know some of you will do it anyway. If you do–against my injunctions–then be sure not to pinch the tube between your tire iron and the rim or you will puncture it.
Seat and Inflate the Tire
Once the beads are within the rim, work your way around the tire, making sure no tube is visible between the bead and the rim. If it is, work the tread from side to side until the tube slips inside. Attach the pump and inflate to about 1/3 of the indicated pressure. Now take a look around each rim to make sure the bead is seated properly on both sides of the wheel. If not, deflate and work the tube back in or tire from side to side until seated. Inflate fully.
Put the wheels back on in the reverse order from removal: slide the axles back into the dropouts and tighten down the quick-release levers; you’ve overtightened if you can’t push the lever back down flat. Reattach the brakes. I repeat, reattach the brakes. On the rear wheel, you’ll also have to be sure to thread the axle into the chain and then seat the chain on the outside cog before putting the axles in the dropouts.