HOW TO FIX A FLAT -  Five Borough Bicycle Club -  www.5bbc.org - July 2018

TOOLS YOU NEED - spare tube, patch kit, tire levers, pump

TOOLS YOU MIGHT NEED - 2 wrenches (if your bike uses hex nuts instead of quick release levers)

COMPLICATIONS - disk brakes, big front baskets, internally geared hubs (e.g. 3 speeds), anti-theft gizmos - all make wheel removal more difficult

REMOVE THE WHEEL - undo quick release lever, unscrew end nut a few turns, take out wheel.  In rare cases you may need to undo your brake's quick release.  Hex nuts?  Use two wrenches if possible, turn counterclockwise on both sides (will feel like "opposite" directions).

REMOVE THE TIRE - Start opposite of the tire valve.  First try by hand - lift up tire with both hands and try to push over rim.  This often works.  Otherwise, use levers - push "spoon" end of tire lever under bead of tire, lever it back to lift up tire, hook other end of lever on spoke.  Repeat with 2nd lever at 2-3 inches away.  If you have a 3rd lever, repeat a few more inches away, middle lever falls out.  Repeat until tire loose enough to remove by hand.  Can also slide lever under bead to pop tire off, but be careful, you can tear the tube.

SEPARATE TIRE FROM TUBE - before pulling out tube, note where valve is with respect to tire, so you can later match the puncture in the tube to the tire.

FIND THE PUNCTURE - remove tube and inflate - listen for hissing noise, rotate tube by cheek or ear until you feel or hear the air escaping.  If needed, ask 2nd person to pump while you search. Mark spot with ballpoint pen 1 inch away from puncture all sides.

FIND THE CAUSE OF THE PUNCTURE - too many people skip this step, and get another flat within minutes.  If puncture is on rim side of tube, look for problems with rim tape not covering spoke holes or protruding spoke.  If puncture is on road side of tube, inspect tire in that area, or inspect entire tire.  Use screwdriver or tip of penknife to pry out glass or other sharp objects in tire.  Exception: a "snakebite" (2 punctures about 1/4" apart), was probably caused by underinflated tires "bottoming out".  Also check sides of tires for damage that lets tube "bubble out".

PATCH TUBE -  To patch, rough up area around puncture with sandpaper or rasp supplied in kit.  You must fully remove the sheen on the tube for the patch to work.  Apply thin layer of solvent (it's not glue) over area, in large circle around puncture, about 15% bigger than the patch (to have some room for error).  Spread it thin with a finger.  After solvent sinks into tube, tube will look dullish and "tacky".  This takes a couple of minutes, be patient.  When area looks ready, peel off bottom cover of patch, press hard onto tube, burnish with coin or tool.  Patch should be ready to use immediately.

OR REPLACE TUBE - if tube has bad valve, large blowout, or other major problem, it must be replaced.  If it's raining, patch kits won't work - don't even try unless you are sheltered.  Always carry a spare!

TEST PATCHED OR REPLACEMENT TUBE - pump it up just enough to see if it holds air.  If patch is flapping on one side, deflate and re-apply solvent at loose area, wait, press down again, or remove and try new patch.

REASSEMBLE WHEEL - put small amount off air in tube to give it shape, insert inside tire.  Put valve through rim hole, pop one side of tire onto rim fanning out from valve area.  Then fan out from valve on other side of tire and pop onto rim.  Most tires can be popped back on by hand - otherwise use tire levers but be careful, don't poke the tube. Make sure valve is at 90 degree angle with rim.

RESEAT WHEEL - add a bit more air and roll wheel around ground while pushing down to help seat tube.  With tire pressure still low, attach wheel back to bike (soft tire can be pushed past brake shoes).  Make sure wheel is centered (happens automatically on front wheel and most rear wheels if bike has "vertical dropouts").  Rear wheel of fixies, 3-speeds and similiar, you must also adjust wheel position for chain tension.  Hex nuts?  Use 2 wrenches if possible, tightening clockwise on both sides at the same time (will feel like opposite directions).

INFLATE TIRE - turn bike right-side up and start inflating.  As you pump, look for lumps or bulges - if so STOP PUMPING, tube is jammed under bead and will blow out, deflate and reseat tube.  If tire looks good, pump up to recommended pressure (printed on tire) or whatever your hand pump can do until tire is hard.

COMPLICATIONS - for rear wheels of 3-speeds or wheels with disk brakes, reattach controlling cables.

CHECK WHEEL AND BRAKES - spin wheel, make sure it doesn't hit anything.  Put back brake quick-release if you opened it.  Test brakes, make sure you can lock wheel.

PACK UP YOUR TOOLS AND RIDE!  If you swapped the tube and the old one is fixable, don't discard it - patch it at home and now you have another spare.