Repairing A Flat Tire
“Rubber Down”
Before we get started on the how-tos of this basic repair, we need to go over an item of basic cycling etiquette. If you’ve ever been advised to turn your bike upside down and stand it on its handlebars and saddle to repair it, you’ve been misled by a neophyte and probable moron. Doing this to your bike is a mortal sin, a disgrace to riders everywhere. Don’t expect to get any road-side assistance from any experienced cyclist if you do this. Beyond the obvious risk of scratching your handlebars or tearing your saddle, you’ll have to remove all your bags from your bike and if you need to remove your wheel, it becomes way more difficult if your bike is upside-down. Always keep your bike right-side-up and, as cycling pros say, “rubber down”. If you need to rest your bike on its side to do any repairs, do so gently, laying it down on the non-drive side, preferably on some grass. But never turn your bike upside-down.
Every self-respecting rider should know how to fix a flat tire (or puncture). This is an essential bike repair that you’re very likely going to need to know how to do during a cycle touring or bikepacking trip. The first time can be daunting only because you’ve never done it before. This is a straight-up case of what FDR would say is nothing to fear but fear itself. It’s actually quite straightforward, and once you’ve done it, you’ll be able to do it anytime with ease. You may want to do a practise repair before you head out on your cycling trip. Practise makes perfect, and having practised this in your garage, you won’t be as intimidated by a roadside repair. Be patient. Approach your tire repair in a methodical manner so you don’t have to undo it all and start all over again in the rain at the side of the road. (Misery.) A cycle touring or bikepacking trip is not a race. The most important thing is to make sure that you’ve got the proper tools and spares and that you know how to use them. Also, keep them in an easily accessible place on your bike, such as your frame bag, so you don’t have to go looking for them when you need them most. All you need to fix a flat tire is the following basic tools and equipment:
Two tire levers
Spare inner tube or patch kit
Emergency pump or CO2 inflator and cartridge
Tire pressure gauge
The process of repairing a flat tire is almost the same for both the front and rear tires. If you have a puncture in your rear tire you’ll first need to shift the chain to the hardest gear (on the smallest cog) before you remove it. Let’s get started.
Step 1 — Remove The Wheel
If you have cantilever brakes, the first thing you’ll need to do is release them to get the wheel off the bike. If you have disc brakes, there’s nothing you need to do with the brakes to remove your wheel. The disc will move in and out between the pads. If your wheel is secured with quick release skewers, just open the quick release. If your bike has thru-axles, unthread the axle and pull out the axle from the frame. If you’re removing your rear wheel, you’ll need to pull back the rear derailer to slide the wheel out of the dropouts. Remove the wheel and remove the valve nut from the valve stem.
Step 2 — Make Some Space
With the wheel removed from the bike, make some space between the tire and the rim by using your thumbs to press the edges of the tire all around until it has been pushed into the well in middle of the rim. You’ll know when you’ve done this, because the tire will be slightly loose.
Step 3 - Remove One Tire Edge from the Wheel Rim
Start near a spoke opposite to the valve stem. Insert the scooped end of your tire lever under the tire to grab the edge of the tire and work it over the edge of the wheel rim. Attach the hooked end of the tire lever to the spoke. Then use the scoop side of your other tire lever to work the rest of only one tire edge over the edge of the rim. Do not remove both edges of the tire from the wheel rims. There’s no need to do so and it will make your life more difficult than it already is with the flat. Near the valve stem, push the tire away from the rim and pull the valve stem out of the wheel.
Step 4 - Remove the Tube
Remove the tube from the wheel and use your hand to carefully check around inside of the tire to ensure that it’s clear of debris and also carefully check the outside of the tire for any sharp objects stuck in the rubber, especilly the tread. Be careful when you’re checking the inside of your tire with your hand. You don’t want to cut yourself on glass or other sharp objects lodged in there.
Pinch Flats
If you don’t find anything when you inspect your tire, you may have a “pinch flat”. A pinch flat is very common. It can happen when your tire is underinflated. A pinch flat is caused by an underinflated tire hitting a square edge bump where the tire is pinched between the bump and the wheel rim. That’s why you always want to ensure your tires are properly inflated to their recommended pressure before you head out on a ride. The PSI is stated right on the tire.
Step 5 — Patching Your Tube (If you Don’t Have a Spare)
Always carry at least one spare tube with you (ideally two or three) and take any punctured tubes home with you to patch later at your convenience. Don’t litter, and think about the environment — patch and reuse your tubes as much as you can. If you don’t have a spare tube, you’ll need to patch the existing tube on the road side. Pump up the tube to find the puncture. Listen carefully and feel with your hands for leaking air. Depending on the size of the leak, you can either patch the hole or replace the tube. To patch the hole, lightly sand the area around the hole for good adhesion (you can use a rough stone for this) and apply pressure to the patch and let the glue set.
Step 6 - Insert Your Tube Back Into the Tire
It can be difficult to get your flat tube inside your wheel, so first just pump it up slightly. To put the tube back in the tire, start back at the valve stem hole. Insert the valve stem. Work your way around the tire, tucking the tube under the tire all the way around. To get the tire seated properly back in the rim, start at the tightest point in the tire next to the valve stem, and using both thumbs, push the edge of the tire back onto the rim. The tire will get tighter as you work your way around the rim. When you get to where the last portion of tire is too tight to push back under the rim, use the scooped end of one of your tire levers to press the remaining portion of the tire back inside the rim by inserting the lever under the tire and lifting it up with your wrist. Check to make sure that no portion of the tube is pinched between the tire and the rim by gently pushing the tire to the side as you work your way around the rim looking for any pinches.
Step 7 — Inflate Your Tire
Reinstall the valve stem nut, and with the tire back on the rim, re-inflate the tube with an emergency pump or CO2 inflator. Using your pressure gauge, check to ensure that your tube is inflated to the rated tire pressure. Bear in mind that some emergency pumps will not be able to get your tube up to the required PSI and you may be forced to ride very carefully on an underinflated tire until you get to the nearest gas station or bike shop where you can use an industrial tire inflator or CO2 inflator. With the wheel reinstalled on your bike, you can get back on the road.
For more information on repairing a flat tire, check out these excellent videos with step-by-step directions.