How to Fix a Flat Tire on the Trail

If you ride long enough, you will get a flat tire. It is not a question of if, but when. On a bikepacking trip, being 30 miles from the nearest town with a flat and no idea how to fix it is a bad situation. The good news is that fixing a flat is one of the simplest bike repairs, and once you have done it a couple of times, you can handle it in under ten minutes.

What You Need to Carry

Every ride, without exception, you should have these items with you: a spare inner tube (or two on longer rides), a patch kit as backup, tire levers (two or three), a mini pump or CO2 inflator, and a multi-tool.

All of this fits easily in a seat bag or frame bag.

If you run tubeless tires, carry a tubeless repair kit (tire plugs and a plug tool) in addition to a spare tube. Tubeless setups are great at self-sealing small punctures, but larger holes need a plug, and if that fails, you need to install a tube to get home.

Step 1: Find a Good Spot

Pull off to a flat, stable area. Flip the bike upside down (resting on the handlebars and saddle) or lean it against something sturdy.

If you have a kickstand or a repair stand, even better. You want the bike stable so you can work on the wheel without it falling over.

Step 2: Remove the Wheel

If the flat is on the rear wheel, shift the chain onto the smallest cog before removing the wheel. This makes removal and reinstallation easier. Open the quick release lever or loosen the thru-axle. For the rear wheel, pull the derailleur back and lift the wheel out of the dropouts.

Step 3: Remove the Tire

Deflate the tire completely if it is not already flat.

Hook a tire lever under the bead of the tire and clip it to a spoke. Insert a second lever a few inches away and slide it around the rim to unseat one side of the tire. You do not need to remove the tire completely from the rim. Just get one side off so you can access the tube.

Pull the tube out, starting at the valve. Be careful not to pinch it on the rim.

Step 4: Find and Address the Cause

Before putting a new tube in, figure out what caused the flat. Run your fingers carefully along the inside of the tire, feeling for thorns, glass, wire, or anything sharp still embedded in the rubber. Check the rim tape too, making sure it covers all the spoke holes. If something is still stuck in the tire and you do not remove it, your new tube will puncture immediately.

Inflate the old tube slightly to find the hole.

If you can hear or feel air escaping, the location tells you where to look in the tire. Two small holes close together usually mean a pinch flat (the tube got pinched between the rim and an obstacle), which is caused by low tire pressure rather than a sharp object.

Step 5: Install the New Tube

Slightly inflate the new tube so it holds its shape but is not firm. This makes installation easier and reduces the chance of pinching it.

Insert the valve through the valve hole in the rim first, then tuck the rest of the tube inside the tire, working your way around the rim.

Once the tube is fully inside, push the tire bead back onto the rim with your hands. Start at the valve and work both directions toward the opposite side. Use your palms, not tire levers, to seat the last section. Tire levers can pinch the tube and cause another flat.

Before fully inflating, push the valve up into the tire and pull it back down.

This ensures the tube is not trapped under the bead near the valve. Check both sides of the tire all the way around to make sure no tube is peeking out.

Step 6: Inflate and Reinstall

Inflate the tire to the pressure printed on the sidewall (or whatever pressure you normally run). Check that the tire is seated evenly on the rim by spinning the wheel and looking at the bead line. If it looks wavy or uneven, deflate and reseat the tire.

Put the wheel back on the bike.

For the rear wheel, loop the chain over the smallest cog, guide the wheel into the dropouts, and tighten the quick release or thru-axle. Spin the wheel to make sure it is centered in the frame and the brakes are not rubbing.

Patching vs. Replacing

Carrying a new tube and swapping it is the fastest way to get back on the road. Patch the punctured tube later at camp or at home, and it becomes your spare for the next flat. Patch kits with vulcanizing glue are more reliable than glueless patches, though glueless patches work in a pinch.

To patch properly: roughen the area around the hole with the sandpaper from the kit, apply a thin layer of glue, wait 30 seconds for it to get tacky, press the patch on firmly, and hold it for a minute. Let it cure for five minutes before inflating.

Preventing Flats

Run your tires at the right pressure. Too low and you risk pinch flats; too high and the tire cannot absorb impacts, which increases puncture risk. Check your tire sidewall for the recommended range. For gravel and rough trails, running toward the lower end of that range provides better traction and comfort.

Tubeless tires with sealant handle small punctures automatically and are less prone to pinch flats. If you are doing serious bikepacking, the switch to tubeless is worth considering. But always carry a tube as a backup, because sealant cannot fix everything.