It’s fitting that “flat” is a four-letter word. Having one at an inconvenient time usually results in a string of other four-letter words. And if you don’t know how to change one, you could find yourself stranded and dialing up two other four-letter words, “Uber” or “Lyft.”
There are alternatives, to be sure. Your average bike shop will charge anywhere from $10 to $20 or more to fix a flat and is more than happy to help – but it won’t come to you. USA Cycling offers 24/7 unlimited roadside assistance, including flat repair – but only to its members who pay at least $50 a year. Most AAA memberships include bike/rider pickup and transport – but not flat repair. (If you ride with a group there are likely several people who are flat-change experts, taking payment only in the occasional hot or cold post-ride beverage.)
Or you could bypass everyone and do it yourself. Of all the bits of bicycle maintenance knowledge that is easily knowable, how to change a flat is the simplest and, in the long run, the most cost-saving.
For the sake of commonality and brevity, let’s assume you are running clinchers (the tires used with a separate tube). Here’s how to become a flat-repair pro in six once-you-practice-it’s-easy steps.
1. Look for the hole
A quick tip before you start: Don’t ride on your flat. No, seriously, don’t. Even. The bicycle rim is a wondrous thing, but its edges can be like knives when a tire comes between them and the road. Prolonged riding on your flat increases the likelihood that you’ll slice your tire, and then you’re definitely walking, Ubering or Lyfting (and, maybe, cursing).
So … to begin. Whether you discover your flat before your ride or you hear the horrible pffffffffffft! (or worse, BLAM!) out on the road, take the time to look at the outside of your tire. Look for the obvious (bits of glass, staples, tacks and other sharp objects) but also the not-so-obvious. By pinching the tire with the thumbs and fingers of both hands, you often can expose holes that you might not see otherwise. If you find something, remove it. If not, don’t worry.
2. Unseat the bead
Another quick tip: Don’t use a flat-head screwdriver here, or a knife, or anything similarly sharp. Again, just don’t. Never. They can damage rims and puncture tubes and tires. Leave them for their intended applications.
This is where tire levers – those curved-tipped plastic, composite or metal tools – come in. (Although there are instances where they’re not necessary, and this depends on how tight the tire is on the rim or if you have bionic thumbs.) But let’s assume that you need levers, like those from Performance, Park Tool or Pedro’s. The curved-tip end of said tire lever fits under the bead (the hard edge of the tire that sits on the inside of the rim). You may have to manually manipulate the tire a bit to get the lever under the bead, usually by applying thumb pressure. (Pinching the sides of the tires together can help free the tire from the bead, too.)
Holding the seated lever with one hand, stand the wheel on its end and use the other hand to flatten the tire at the point where you have inserted the lever. Then, continuing the off-hand pressure to ensure the bead stays off the rim, push the lever away from you until more of the bead “pops.” Continue pushing the lever until the entire bead is off the rim. (You may see people using two or more levers to remove their tires, but if you apply off-hand pressure to keep the initial part of the bead off the rim, you often can do it with just one. If not, the hooked end of the lever locks onto a spoke, then you use another.)
3. Remove the tube
With one side of the tire off the rim, you can pull out the tube and remove the valve. (For Presta tubes, make sure to remove the round nut, if you use one, at the base of the valve; for Schrader valves, remove the valve cap.) If you have the time and a mini pump, you can put some air in the tube and try to locate the leak, which in turn could help you locate the spot where something went through the tire. Again, if you can’t, don’t worry.
4. Inspect the inside tire casing
Using a new tube inside of a tire that hasn’t been fully inspected is a good way to get a lot of practice changing consecutive flats, assuming you have enough tubes. So don’t. If you can’t find the offending puncture point on the outside of the tire, you might find it protruding from the inside casing, waiting like a vampire fang for another victim.
You can remove the tire completely from the rim, turn it inside out and look closely. Or you can leave the tire on and run a finger on the casing to feel for anything sharp. The problem with the latter: You might find something sharp, really sharp, and cut your finger. Here’s a tip: Pack a couple of sheets of toilet paper in your saddle bag. Yes, toilet paper. (I wrap mine around a CO2 cartridge.) Run the TP gently inside the casing and if there’s something there that could puncture a tube, the paper will most likely snag on it – and then you can remove it or wiggle it loose.
5. Partially inflate the new tube and insert
It’s easier to install a partly inflated tube. A few puffs from a pump or a blip from a CO2 cartridge are enough. If you have completely removed the tire, this is the time you remount by placing one bead over the rim, leaving the other bead off. (You may need to use a tire lever to get the first bead over the rim.) Then place the tube inside the tire casing and insert the valve. It’s a good idea at this point to make sure the tube is all the way around the casing, with no folds or twists.
Two other quick tips: 1) It’s a little thing, but aligning the center of the tire label with the valve hole is a good way to find the valve next time you need to pump your tire; 2) make sure your rim strip covers all your spoke holes. If not, you’ll be doing this all over again because the sharp edge of a spoke hole will pop a tube.
6. Reseat the bead and inflate
The final part is a two-step process that begins with some valve fiddling. Start seating the bead inside the rim at the valve hole, and while doing it push the valve partway up into the tire. Then pull the valve back down toward the hub, locking the bead in place. With your thumbs as levers, begin to move around the rim, lifting the bead up and over the rim. Make sure as you do this that the bead doesn’t pop off “behind” where you’ve already placed it, and be careful the tube doesn’t extrude as you’re seating the bead; that causes the aptly named “pinch flats.”
As you get closer to completing the circle, it could become more difficult to seat the bead. At this point there are two ways to go, and neither is wrong or right. You can use a tire lever, with the curved tip pointing down, to lift the bead over the rim – but be careful you don’t pinch the tube. You can also “roll” the bead over the rim using the top of your palms. (This is best done with gloves on.)
Once the bead is seated, work your way around the tire by pinching in one bead, and then the other, making sure you don’t see any tube sticking out from under the bead. If you do, manually work the tube up and into the casing; pinching works best. If you see no tube on either side, inflate the tire to about one-third of your final pressure and check that the bead line – the molded seam on the sidewall – is visible above the rim all the way around on both sides. If not, deflate and work the tire manually until the bead line is visible. Then reinflate, check the bead line and if it looks good on both sides, you’re good to inflate all the way.
Why inflate twice? If the bead line is below the rim and you inflate fully from the start, the tire will have a low spot that will be visible when you spin it and palpable when you ride on it. If the bead line is too high above the rim and you try to inflate all the way, there’s a chance the tube could push out from under the tire and, as you near full inflation, cause an explosion of popped rubber. No one likes that sound.
The bottom line
Although it’s taken you more than 1,400 words to get here, changing a tire is really easy and, like all things, becomes even easier with practice. Taking some time to do it when you don’t need to guarantees that it’ll be a lot easier when you do.
If you’d like some pro help, your local Performance Bicycle shop has free Spin Doctor workshops that cover many basic maintenance skills, including how to change a flat. For a schedule, check out our website or visit a Performance store near you.