BicycleSource Newsletter

One thing I'd like to point out is that tubes are super cheap if you order them online. I RARELY patch a tube, because for the minimal cost of tubes, it's just not worth the risk that the tube will fail again. The steps below apply nevertheless (with the obvious exception of 7 & 8)... you still need to identify what caused the puncture!

1. Gather the required materials:
- flat repair kit OR a new tube
- soapy water
- tire irons

2. Inspect the Tire
You'll want to find out what caused the flat so that it does not simply happen again after your repair. Most commonly, the flat will be caused by a puncture from the outside (eg, nail, thorn etc). Somewhat less common is a "pinch flat" which is caused by the tube wrapping over on itself inside the tire and "pinching" a little hole. Usually this is caused by riding on a tire with a lower-than-recommended pressure. If you can not easily spot the culprit, wait until step 6 where you'll inspect the tube itself.

3. Release the Brakes and Remove the Wheel.
Most bikes now have a "quick release" system - just flip the lever back and pull off the wheel. If yours doesn't you'll need a wrench.

4. Unhook One Side of The Tire
Slide a tire iron between the tire and the rim and pry out the tire. Be careful not to puncture the tube, and do not attempt to use a screw driver in place of a tire iron (unless you're ok with puncturing your tube and possibly damaging the rim). Slide the tire iron around the wheel until you have one side completely unhooked. Some tire irons have a fancy hook allowing you to keep one tire iron by latching it onto a spoke, while using another tire iron to slide around the tire.

5. Remove the tube from the tire.
Start at the valve and be careful not the bend the stem. Pull slowly to avoid creating additional ruptures. At this point you'll want to inspect the rim for any foreign debris or damage to the rim. Even if it is not related to *this* flat, it doesn't mean it won't cause problems for you in the future.

6. Find the hole in the tube.
Use your pump to inflate the tube a bit, and then submerge the tube in soapy water. Look for bubbles coming from the puncture. Be sure to make sure there is only one puncture. At this point I also like to look back at the point on the tire and ensure that whatever caused the flat is not still there. For example, if the tube is punctured at 4 o'clock (relatively to the valve) on the inside, check your rim at the same spot on the inside to make sure there is no debris or damage spokes poking out.

7. Prepare the puncture.
Dry the area around the puncture if it's still wet from step 6. Lightly scratch the spot surrounding the puncture. Apply the glue and allow a few seconds for it to start to harden.

8 Repair.
Apply an appropriately sized patch and hold firmly for several seconds. Ensure the edges of the patch are glue down well, or the patch may peel off. Applying some talc powder will prevent friction from peeling off the patch inside the tire.

9. Replace the Tube.
Again, start with the valve and be careful not to damage it. I find this step easier if you put just a little bit of air into the tube using the pump. Also, make sure that the tube is not twisted at any point. Most tubes have a seam along the inside which you can follow along to make this part a little easier.

10. Pump up the tire.
The video neglects an important step at this point which you'll find most experienced mechanics do. Before fully inflating, inflate the tire to about 1/3 of maximum and "bounce" the tire lightly on all points. The purpose of this is to ensure that the tire is evenly seated on the rim at all points. You should also check visually to make sure that both sides of the tire look the same. Once this is done, you can fully inflate the tire.

11. Put the Wheel Back On
Ensure it is tight, but remember that this is not a car wheel. Over-tightening could stress your frame and/or hub.

12. Reattach the brakes
Make sure you test them out before you really need them next!
Post a Comment
1 comments posted so far.
Posted By: Richard Charrington on August 9th, 2009
Might be a good idea to put the rim back on the tire between 9 and 10?!