Issue Date: April 6, 2008

Fixing a bike flat

A spare tube works until you can make a patch.

1. Don't try to repair a tube on the road. When you get a flat tire, it's actually the tube inside that needs to be patched. Carry a small kit with a deflated spare bike tube, a pump or air cartridge and plastic bike tube levers. "A bike tube is $6," says Ken Whelpdale of USA Cycling. "The time to fix a flat is when you are at home. Until then, just put on a new tube." (This is not to say that a well-patched tube isn't as sturdy as a new one. "I have frugal friends with a dozen patches on a tube," he says.)

2. Do trail triage. Use plastic bike tube levers, such as those made by Pedro's for $3.99, to loosen the tire from the rim and pull out the damaged tube, says Aaron Corso of Belmont Wheelworks in Belmont, Mass. But be careful as you pry the tube from the tire: Even plastic levers can cause a puncture if you aren't gentle. Pop in the spare tube, pump in the air and finish your ride.

3. Find the hole once you're at home. Yeah, you can use a bucket of soapy water to locate the leak (bubbles will form where the air is escaping), but there are other methods, too. Corso says you can listen for leaking air and feel for the spot and find it just as fast. Once you find the hole, use a safety pin to mark the spot, Whelpdale says. Yes, a safety pin. "The hole is already in the tube," he says. "This helps you pinpoint the location."

4. Rough it up. Buy a patch kit and use whatever abrasive came in it (or an emery cloth or sandpaper) to rub the area around the hole, Whelpdale says. Then, clean the area well with alcohol. Both steps help create some texture on the tube and prepare it so the patch and glue you apply will make the best seal. Wait 10 minutes for the glue to dry before refilling the tube with air.

5. It's OK; you can cheat. There are quick-fix products you inject inside the tube that work as well as a patch. Slime and Bontrager Super Juice sealants are two, Corso says.

-- Lisa Jaffe Hubbell