How to Fix a Flat Bike Tire: Patch or Replace the Tube

Carry a spare tube, levers and a pump, and learn the order once. This page is part of Plan a Ride; the steps follow Park Tool’s published repair guides.

What to carry

Bring at least enough to get a flat tire on your bike fixed⁷. That means a spare inner tube, tire levers and a pump⁷. A tight bead needs the levers¹. Park Tool’s patch guide adds a patch kit, and lists a marking pen, rags and alcohol solvent as useful items².

These steps apply to a traditional tire-and-inner-tube setup². Tubeless tire bodies cannot be patched with stick-on patches².

Step by step

• First, remove the wheel. On a rear wheel, shift the derailleur to the outermost gear and the innermost front chain ring, which gives the most chain slack⁸. With disc brakes, no pad disengagement is needed⁸. On a front wheel, guide the wheel down and out of the fork⁸.
• Second, deflate the tire. Deflate the tire completely, because even a small amount of air left in the tube makes the tire harder to get off¹. Remove the valve cap and press down on the center pin to release the air⁹.
• Third, lift one bead. Engage one tire lever under the bead, then a second lever 1-2″ (25-50mm) from the first, and pull both toward the spokes¹. Do not use a screwdriver, knife or other sharp object¹.
• Fourth, pull the tube. Starting opposite the valve, pull the inner tube from the tire¹.
• Fifth, find the cause. Inspect the tire as well as the tube, because a nail or piece of glass may still be embedded in the tire or tread¹. Check inside the rim for the rim strip, sharp corners or protruding spokes¹.
• Sixth, replace or patch. See the next section.
• Seventh, refit. Inflate the tube just enough to hold its shape and install it inside the tire¹. Seat the beads by hand, and use a lever only as a last resort, with care not to pinch the tube¹.
• Eighth, check the bead and inflate. Inspect both sides of the tire for bead seating and for any sign of the tube sticking out¹. Inflate to full pressure and check with a gauge¹.
• Ninth, reinstall the wheel. With quick-release, tighten the axle until the lever meets resistance at 90° from the frame or fork⁸. A wheel that is not securely mounted in the dropouts can come out while you ride, possibly causing injury⁸.

Replace the tube or patch it

Simply replacing the punctured tube with a new one is always the safest and most reliable procedure¹. When in doubt, replace the tube¹. On the road, install the spare and save patching for home, with good light and proper solvents⁷.

Finding the hole

To fix a flat, first locate the hole in the tube². Re-inflate the tube to at least twice its normal width if possible². Hold it close to your lips or near your ear and move it around its circumference². If that fails, submerge the tube in water and watch for bubbles².

Patching

Mark the hole with four marks, one to each side². Do not mark close to the hole, as the mark may be sanded off². Lightly abrade the area around the hole². Excessive sanding or heavy pressure can groove the rubber and cause patch failure². Clean with a rag and alcohol or a solvent that leaves no film, and allow the area to dry completely².

Patch type	Use	Key steps
Pre-glued	A temporary trailside fix for emergencies; replace the tube as soon as possible2	Peel from the backing, center on the hole, apply pressure2
Glue-on (vulcanizing)	Less convenient but much more durable when properly installed2	Thin coat of glue, let it dry, press on, hold pressure for over a minute2

After a minute or two, check that all the edges of a glue-on patch have adhered to the tube². Do not test any patch by inflating the tube outside the tire, since that can weaken the bond².

Read the flat

The shape of the hole tells you how to prevent the next one. Double slits from a pinch between the rim and an object in the road call for more air pressure or wider tires¹. A cut at the valve core, commonly from misalignment or low pressure, calls for a tube mounted straight in the rim and a pressure check before each ride¹. A crooked valve can cause a flat later, so align it pointing straight toward the hub¹.

Where to get a flat fixed in Chicago

• The Recyclery, 7628 N. Paulina St., next to the Howard station⁴. Its Open Shop lets you fix your own bike with its tools and help from volunteer mechanics, with no appointment³. Open Shop runs Monday 5 to 7 pm, Thursday 7 to 9 pm and Saturday 11 am to 2 pm⁴.
• Working Bikes, 2434 S. Western Ave., has a full service department staffed by expert mechanics⁵.
• Igor Does My Bike, 5454 N. Broadway St., offers a four-day turnaround for tune-ups with appointments⁶.

For more options, use the Chicago bike shop directory and community bike shops. New to riding here? Start with biking in Chicago for the first time.