7. How to Fix a Flat Tire
How to use a patch kit to repair a tube. Also demonstrates how to remove and install a tire.
Fixing a flat tire is one of the most common bicycle repairs. I personally recommend replacing a tube when you get a leak, but that is not always possible. If done properly, a patch will work just fine. Here’s how it’s done.
With the wheel removed from your bike, inspect the outer surface of the tire to make sure there are no sharp objects like a thumb-tack or thorn stuck in the tread.
Remove the valve cap and fully deflate the tube by depressing the valve stem with the hooked end of your tire lever. There are two main types of valve stems, a schrader valve and a presta valve. This tutorial is based on a schrader valve, but I will be covering the different valve types in another tutorial.
Now it’s time to remove your tire, one side at a time. Choose a section of tire that is away from the valve and hook one of the tire levers under the bead, directly in line with one of your spokes. Pry one side of the tire bead over the edge of the rim, and then hook the end of the tire lever to the nearest spoke. Insert another tire lever two spokes away from the first, and a third another two spokes away. Now the middle lever should fall out, and you can continue the process. When the tire is loose enough you can just run a tire lever around the rest of the rim to pull the whole side over.
After you have removed one side of the tire, the other side should come off very easily.
Now remove the tube from the tire, and try to keep track of where it was positioned in relation to the tire. Inflate the tube to approximately twice its original size. This will expand the hole making it easier to find.
Listen carefully to the entire circumference of the tube; you should hear a hissing sound that will indicate where the leak is. As a last resort you can submerge the tube in water and watch for bubbles, but you’ll want to avoid doing this as you’ll need the tube to be completely dry in order for the patch glue to work.
Once you’ve found the leak, take note of whether it is on the inner or outer side of the tube.
If the hole was on the outer side of the tube, inspect the inner surface of the tire in that spot to make sure the object that caused the puncture is not still stuck in the tire. Double check the entire inner side of the tire by running your fingers along the entire surface, feeling for obstacles along the way.
If the hole was on the inner side of the tube, inspect your entire rim to make sure there are no sharp burrs in the metal, and that the rim tape is properly protecting the tube from your spoke ends.
Now that the rim and tire are clear, it’s time to patch the tube. Select an appropriate sized patch for the hole. Use the sandpaper or scraper provided in your kit to buff the surface of the tube for an area a bit larger than the patch. You need to buff the tube so that it is no longer shiny. If the molding line is running along the area where the patch is to be applied, you must sand it down completely, or it will provide an air channel. Once buffed, avoid touching that area with your fingers.
Apply a dab of rubber cement, and then spread it into a thin coat, using your cleanest finger. Work quickly. You want a thin, smooth coat of cement; if you keep fiddling with it as it begins to dry, you’ll risk making it lumpy. The thinner the cement, the faster it will dry. It is very important to allow the cement to dry completely.
Peel the foil from the patch and press the patch onto the tube firmly, squeezing the patch tightly onto the tube.
Now inflate the tube so it is round and place it evenly into the tire. The first bead of the tire should fit easily onto the rim. Make sure you line up the valve stem with the rim’s valve hole.
Carefully fit the valve through the hole and place the cap on to keep it from falling out again.
The outer bead is harder to install, although most tires can be re-installed by hand. Staring at the valve, work the bead onto the rim using both of your thumbs.
You should never use tools to install the tire, but very tight tires may need some help. Kool Stop makes a great tool called a bead jack, which helps to pull the tire bead over the rim.
Once the tire is seated, inspect the outer edge on both sides to make sure it sits evenly all the way around, and push the valve down into the tire to make sure it didn’t get caught between the tire bead and rim.
Inflate the tire to the recommended pressure, which should be written on the side. Make sure to inspect the tire a few times while you are inflating, to make sure the tire remains seated properly and doesn’t start to bulge anywhere.
Once the tire is fully inflated, install the valve cap and put the wheel back on your bike.
I live on a bicycle and I used to get flats all the time because of poor road conditions and high tire loads. Fixing a flat is time consuming because I have to remove loaded front and rear bike racks with milk crates loaded with gear and homemade panniers.
I tried Slime, I tried thicker inner tubes, I tried homemade liners. Then one day I put an old 27" worn out old school road bike tire inside my 28"/700c x38 cross tire. It fit perfect after I cut the steel bead away with a scissors.
I reassembled the tire on the rim with no difficulty, partially inflated the tube to... Read more >>
The rim width of my 700c wheels is 25mm. I am therefore assuming these are hybrid wheels and require thicker tyres. Can anyone advise me whats the thinnest tyres I can fit onto my wheels?
Ibie... Read more >>
I took my bike to a shop to get a replacement rear tire. (Old well maintained Centurion LeMans 12-speed) The shop took the tire off, swapped the tire and tube, and put everything back. I know that they lubricated the chain because it was greasy when I checked it. But when I pedaled home, it made a clacking noise. Seemed to be related to pedaling, not so much when I was coasting, more clacking at higher speed. I couldn't put it in the lowest gear. When I got home, I removed the saddle bags and slipped the quick release wheel out of the forks (just an inch or so) then replaced it. Seemed... Read more >>
So I'm not an expert, but I have changed many, many bicycle tires over the years. So why is it BOTH of the brand new Kenda 26 x 1 3/8 tires I put on my 1973 Raleigh Sports refuse to seat properly on the rims? It feels like I'm riding one of those clown bikes with elliptical wheels. I deflated and checked that the tube is clear of the bead and tried everything else I can think of. It's as if the sidewall width varies by 4- 6 mms. Suggestions anyone?... Read more >>
The wheels on my mountain bike are 26x1.5 to 26x(something over 2). I bought the thinnest tire I could that fits this frame (26x1.5) and ordered tubes of the same size. For some reason the tubes have a slightly larger diameter than my tires. Is there a reason for this? I currently have slicks that are 1.90 with tubes to match and those work and fit just fine. For some reason I'm having problems getting the 1.5s to match up. Any thoughts?
[attachment=4592]... Read more >>
Hi, I am currently trying to develop bicycle tyres that will never go flat.
If you will be interested in such products you can share your views by
completing the short survey at the link below:
Thank you!... Read more >>
Just thought I would throw this out there and see what hits. I am currently running a 27x 1 3/8 rear tire. Does anyone know of wider?... Read more >>
I purchased a road bike that is a lemon I'm afraid.
I noticed I could hardly pump up the rear wheel because the inner tube would actual push out and push a small part of the tyre off the rim.
Decided to run the rear tyre with a softer pressure at around 80-90psi, when riding obviously with my weight the pressure was too much and caused a part of the rim to jump off this must have caused the inner tube to pinch because with an almighty bang it went and I ended up walking the bike home.
Question is did this happen because my inner tube was oversized? The ty... Read more >>
I'd like to buy some new tires for my road bike. The road bike is a 1981 Free Spirit Pinnacle and the bike has steel rims that cannot accept pressures over 75 PSI without blowing out. My LBS has been giving me tires that require 90 PSI. When I pump them up to near 90 PSI (85 PSI) they blowout. When I under-inflate them to about 60 to 65 PSI, they have problems and get pinch flats.
My front tire was replaced when I bought the bike because the first time I rode the bike it got a puncture (the bike had original tubes and this happened in 2011) and the LBS replaced the front tire and ... Read more >>
I looking at moving to a new home that will be about a mile down a gravel road, does anyone know a good tire that will work well on both gravel and paved roads? The ride to work will be just over 6 miles (1 on gravel and 5 on paved roads).... Read more >>
I've been using the Peugeot Premiere racer I got given by my neighbour a lot recently, mostly at weekends but I've even been riding it to work, the problem is I have now had two punctures on the bike, always on the back wheel and I think they are always from hitting drain covers or bad repairs in the road.
The front wheel seems like the original wheel but the back one has been replaced with a fairly new one, the rim seems slightly wider and flatter then the front wheel, the tyre is also newer, it's a Nutrax one whereas the front one is a vintage Michelin select.
My son's bike has these numbers on the tire: 700c X 40c 28 X 1 5/8
My son's complaint about the tubes that I buy, that should work based on these numbers, is that when he inflates the tube, then it pokes out from underneath the tire. So what size should we buy, and any suggestions of where to find it? Looking online, it looks like 700c is often equated with 27".
And tied into this question is, he hasn't ever used a liner, but he has frequent flats. I'm thinking of getting a couple of liners, but do you have to adjust the tube size when you use a liner?
T... Read more >>
Not a bike repair guy, but love bikes and mechanical stuff..anyway, got a problem here I don't understand...maybe one of you guys can help. Got a flat on the back tire of my Trek mountain bike and removed the wheel. Then I got the tire unseated (my word) to get to the inner tube and removed the tube. Here's where I'm stuck: I want to replace not only the tube, but the tire itself, which has the sidewall damaged in two spots.
Trouble is, I can't get the damn tire off the rim. Half of the tire is like glued on the flat part of the rim!
I've searched up and down the internet, h... Read more >>
Back in May I had a blowout. My grandpa buys me two new Hutchinson tubes and a new tire for the front wheel. Well, here it is, August, and my rear tube got punctured. I go through tubes quickly, I have no idea why, I guess it is because I ride on the sidewalks of my town where there is (strangely) shards of glass, nails, and other things on it.
So my tube got punctured. I was planning on using a patch kit a friend had and said I could use if I ever needed it. So today, I took the tube out of the tire to find where the puncture was.
It was quickly found. It was a huge ... Read more >>
The original tube size is 26 x 1.9/2.125. The one I got from the bike shop is 26 x 1.25-1.75.
Can I use it or is the size too small?... Read more >>