I’m fixing a hole where the rain gets in
And stops my mind from wandering
Where it will go
—Lennon/McCartney

NOTE: I wrote this post many months ago about fixing flat tires mainly because David Millard and I have never gotten around to hosting an in-person basic repair workshop for the club and I thought that this might provide some guidance for the interim. That said the last thing we need is yet another article or YouTube video on how to fix a flat bicycle tire. I’ve looked at quite a few of them and for the most part they cover the basics okay. So this article and the ones to follow are redundant and I would refer you to the Internet to get your education. However I think I organize the information more logically than what you’ll find by hunting on the Internet albeit in words rather than through show-and-tell and I try to catalog the many considerations involved in a repair.
We did a ride from our house that we’ve done many times. There were a couple of spots that had lots of broken glass recently and I warned Roger when we got to them. I should have paid attention to my own warning. The next day my rear tire was flat. It was about time since I hadn’t had a flat in several months; These days I seem to average a flat or puncture about every two to three months. They also tend to come in spurts—several flats in a short period of time and then nothing for a while. And sometimes I don’t fix a flat carefully and then I have to fix it a second time. I do tend to get more flats in winter when more debris is washed into the road and water makes it adhere to the tires. In thinking about it I’ve likely fixed at least 250-300 flat tires in my life and that’s just counting my flat tires and not other people’s. It’s become second nature, almost automatic.
I don’t think anyone fixes their own car tires when they flat. When we get a car flat, we call AAA or somehow get it to a shop and pay them to fix it. A flat in a car tire is harder to fix than in a bike tire as you need a jack to lift the wheel off the ground. Car tires don’t have tubes and a puncture caused by a nail is repaired very similarly to how we would fix a flat in a tubeless tire: tire plugs. At least if you have to remove a bike tire from the rim it doesn’t require heavy machinery as it does with a car tire. But the use of tubes makes the repair of a bike tire a bit more complicated.
Fixing a flat is a task many cyclists approach with trepidation. Certainly fixing a flat when you’re at home and can take your time is a lot less anxiety provoking than trying to fix a flat when you’re on the road, your fellow Spokers are watching you and wondering why it’s taking you so long (or perhaps expressing beaucoup sympathy and thinking ‘better thou than I’), and you’re tired and sweaty.
I won’t opine “it’s so easy!” because I know any unfamiliar task doesn’t feel like it is. In my case it is generally easy only because I’ve done it so many times that I’ve got a routine that works for me. Practice may not make perfect but instead “good enough”. I’ve also made just about every mistake in the book and experienced some unreal and strange circumstances that had me bemoaning my fate (like having seven flats on one ride). That said fixing a flat when it’s raining hard—been there, done that—is never easy!
Preliminaries. If you don’t carry supplies either to fix a flat or replace your flat tire, then you are at the mercy of other people. If you’re riding with others, you will have to borrow what you need from them assuming that they did due diligence and packed repair material. If you’re riding alone, then you will have to depend on the kindness of strangers, proceed by foot or otherwise to a bike shop, or arrange a lift home all of which are inconvenient. I’ve been that stranger that hapless cyclists by the side of the road have begged for help. I’ve loaned them spare tubes, a pump, and even demounted a wheel and then replaced a tube. It’s not that I mind helping people but it can be an imposition when I’m in a hurry. I’ve also–gasp!–been that person by the side of the road. In my case it was due to a severe gash that made the tire unrideable. Not even a tire boot would have worked. I was saved by a fellow Spoker, Walter Teague, who had made it a habit to carry a spare tire because he had experienced the same quandary in the past. Needless to say I started carrying a spare tire from then on.
All of this is to say: you should carry what you need to deal with a flat tire even if you don’t know how to use them. At the very minimum that means a spare tube, a pump or CO2, and tire levers. A spare tube is useful whether you’re running the common clincher tire or tubeless tires. (If you’re one of the few dinosaurs still running sew-ups/tubular tires, then you already know what you need to deal with a flat.) It is possible to demount a clincher tire without tire levers and just your hands but that’s getting near impossible to do nowadays because rim/tire specs are tighter than ever due to the rise of tubeless tires.* Tire levers are cheap, light, and small. So save the he-man/she-man demonstrations for other tasks and carry tire levers. How many levers? Usually you end up buying a set of three. But I’ve never needed to use more than two.
*In fact I had to fix a flat on Roger’s bike today in the shop and I could not get the tire bead off the rim bead shelf no matter how hard I pressed with two thumbs. I had to resort to a screwdriver–something I know is playing with fire and likely to cause more problems than it resolves–to get the bead to start to release. His tire is a newer Schwalbe. It was equally difficult to get the bead to reseat under inflation. On the road this would have been meant calling for a ride home.
Another warning: make sure your spare tube is the right size for the wheels and tires you’re running. That may seem obvious but it’s not, at least to some people. I helped a cyclist who had a spare tube with her but it was the wrong size for her wheel. It was impossible to use the spare and I wasn’t carrying the right size spare either. (She had a Bike Friday with 20-inch wheels.) That said it is often possible to stuff a bigger tube into a smaller wheel. The tube might be folded over onto itself but it will inflate and you can get home safely and replace it with the correctly sized tube. Stuffing a smaller tube into a bigger tire might work but it can be dangerous or impossible. If you have to stretch the tube a lot to get it over the rim, you’re also stretching your luck. Furthermore inflating a small tube in a large tire–even if you get that far–is going to stretch the tube like a balloon and it may fail.
Yet another warning: make sure your spare tube is protected. When you buy a spare tube it comes inside a small cardboard box and maybe it’s even inside a small plastic bag. Don’t make the mistake of sticking that spare tube in your saddlebag without some kind of covering. You’re likely tempted to ditch the cardboard because of its size. At least keep the plastic bag or wrap the tube in something like a sock. Why? Because the minor jostling and movement of the tube inside your bag along with any other tools can actually abrade the rubber and make a hole that you won’t notice until you need to use the spare. Don’t ask me how I know this.
Yet another warning: make sure your pump and/or CO2 inflator has the correct type of valve head for your tubes. Most of us run tubes with Presta valves. But Schrader valves–the kind on automobile tires–is much more common. Nowadays most pumps and inflators have a head that can be switched to either. But that isn’t always the case. It doesn’t matter which kind of valves you have–just make sure the head on your pump or inflator matches.
Fix it now or later? When you’re out on the road and get a flat, the first decision is whether to fix it immediately or just put in your spare tube. You do have that spare tube with you, right? As well as tire levers and a pump? If you don’t, then you’ve either got to cadge them from your ride mates (if any) or patch it immediately. If not, then it’s ‘game over’ and time to call for a lift home or to the nearest bike shop. Usually I don’t fix a flat while out riding. It’s time consuming plus I don’t have the convenience of a clean work bench, a decent floor pump, and a repair stand. Instead I’ll put in the spare and deal with the repair when I’m home.
There are some circumstances when I’d choose to fix the flat immediately rather than just put in a spare. If I’m on a long ride especially one that’s going to take me somewhere remote (and no cell service), I might fix it right away. This is because I want to ‘keep my powder dry’ i.e. still have a spare tube. But it also depends on the circumstances. If it’s an inconvenient location to do a repair (eg. muddy, dense traffic with no safe spot, etc.), it’s getting dark, or especially if it’s raining, then I prefer to use the spare. If you’re a real boy scout, then you’re carrying two spares and the decision is easy: do the repair at home.

Of course in order to do the repair on the road you have to have either a patch kit with a viable tube of ‘glue’ or glueless patches. Do you have at least one of these in your kit? If you don’t, then you’ll have to use your spare. Speaking of patch kits, those little plastic boxes contain a few patches, a glue tube, and a small square of sand paper. After you’ve opened that sealed tube of glue, it has a very limited life—maybe a few months to a year. This is because the ‘glue’ contains a solvent to stay liquid and it eventually completely evaporates even when capped. I have also discovered, of course at an inopportune time, a glue tube that had completely dried up even though it had never been opened. So they just have a limited life and you should check them from time to time by gently squeezing the tube to see if the glue is still semi-liquid; if the solvent is gone, the tube will feel lighter and it will compress easily. You can pick up replacement tubes at any bike shop. By the way patch ‘glue’ is really a misnomer. It’s not technically glue; it’s a vulcanization fluid that partially dissolves the rubber on the surface of the tube and the back of the patch so that they actually bond together directly rather than being held together by a third compound, i.e. glue

Glueless Patches. Glueless patches are patches with an adhesive backing so no separate tube of glue is required. You peel off the protective backing and slap in on the tube over the puncture. It’s faster and you don’t have to worry about applying glue properly or that you even have a good tube of glue. They usually come with a small piece of sandpaper too to roughen up the puncture area for better adhesion just as the patch kits do. There is one caveat: glueless patches may not last long before the air starts to leak out again. But they usually last long enough to get home. I’ve had glueless patches last indefinitely and I’ve had some fail within a day. The reason is that the adhesive is just that, an adhesive, and it’s not vulcanizing the patch onto the rubber tube. Vulcanization is a chemical process that produces a stronger bond between the rubber tube and the patch. If done correctly, a “glued” (=vulcanized) patch may last indefinitely. If you’ve used a glueless patch, you should consider replacing it with a glued patch later on; or you can just hope that it will last indefinitely. In my experience taking the time to clean and roughen the tube with the sandpaper and then repeatedly pressing very firmly all around the patch with the blunt end of tire lever after putting it on helps them last longer. Consider them a temporary repair or at least don’t be disappointed if you get ready for a ride later on and find out your tire is flat long after you put on that glueless patch and have forgotten about it.
Speaking of repair stuff you should have with you. The idea of having repair stuff with you is to be more self-sufficient. If that’s not important to you, then by all means outsource your repairs to a professional (or a really good friend!) You did know that AAA provides roadside service for bicyclists, right? Of course you have to be a member. They can pick you up and take you home, to your car, or to a bike shop!
Besides the bare minimum elements to handle a flat—pump or CO2 cartridge(s), tire irons, spare tube—there are other things that are useful to put in your saddle bag or Camelbak. Even if you don’t know how to use them, someone else on the ride might and then can assist you. What are those things?

A multi tool: a compact tool that has the usual Allen wrench fittings for bike parts such as your stem, screwdrivers, and Torx fittings. Bolts may come loose through time and you can tighten them up while on the go. The caveat is that all bolts technically have torque ratings so that you don’t tighten them too much and end up stripping the threads or breaking the part. Believe me, I’ve done that and it’s a total bummer when the broken part, e.g. the stem, makes the bike unrideable. So you need to know what you’re doing and be careful when using it. By the way these days all nuts and bolts on bicycles are metric and all bicycle multi tools are metric. But if you have a really old American- or British-made bike or individual Allen wrenches, they might be Imperial. Make sure you have the right kind for your bike. Also make sure that your multi tool has the Allen and Torx fittings for the parts on your bike. If you’ve got a Allen bolt with a rare 2.5 mm Allen head, you’ll need to ensure that’s included in your tool.

Tire boot: Basically it’s a really large patch to put in your tire if you happen to have a big gash. This prevents the tube from bulging out of the tire casing. You can make one out of an old tube. The trope is that in a pinch if you don’t have a dedicated tire boot, you can stick a dollar bill in your tire. But I have tried that and if the gash in your tire is big enough, it will still bulge out and be ineffective.

Spoke wrench: if your bike has rim brakes and your wheels have traditional spoke nipples, then carry a spoke wrench. They’re very small and light. Spoke nipples generally come in three different sizes so you’ll need to have the right size wrench for your nipples. If you break a spoke or your rim otherwise goes out of true (ie. develops a wobble especially a lateral one) and suddenly starts to rub against your rim brakes, you’ll need to tweak the spoke tension in your wheel in order to reduce that. Of course you’ll need to address this more carefully at home. With disc brakes rim wobble is much less an issue since it won’t rub against the brake; you should get the wobble fixed but you won’t have to do it while on the road.

CO2 inflators. Instead of a pump you can carry a CO2 inflator with a couple of cartridges. This is very fast and much less effort than pumping up a tire with a mini pump. The caveat is: when you’ve used up your cartridge(s), that’s it. With a pump you always have a means to add more air. Why should you be worried about running out of cartridges? Because you may get a second flat or you may not have fixed the flat well and thus have to repeatedly stop and pump more air to make it home. What happens more often that you think is that you never cleared the cause of the flat—such as a piece of glass embedded in your tire—and after putting in your spare, you flat again. (CO2 cartridges are disposable but you can mitigate the environmental impact by putting them in the recycle bin.) A pump also allows you to finely tune the inflation whereas a CO2 cartridge usually has to be fully used at once. (There are some inflators that allow you to adjust how much CO2 you can inject.) Better to have a pump. Of course a couple of CO2 cartridges and a simple inflator are usually lighter than a pump.
Most people don’t realize that CO2 bleeds out of the tire pores much more quickly than air so when you get home, you should deflate the tire and pump it up with air or else you’ll end up with a flat tire in a matter of a couple days even though there is no puncture. One more thing: when you inject CO2 into your tire, it is very cold due to the adiabatic effect. Know that if you are using tubeless tires with sealant, thermal shock from the very cold CO2 renders some sealants useless. CO2 also degrades some sealants even if you inject it slowly to reduce thermal shock. So if you’re using tire sealant, either use a pump or plan on doing some additional repair work when you’re home, e.g. checking and probably replacing the sealant.
Most CO2 inflators are all-or-nothing: once you put the head of the inflator on your valve and then screw in the CO2 cartridge to open it, all the gas is going to be released. (Some inflators allow you to adjust how quickly and how much you’re injecting and then shut it off.) You should practice this at home before you have to do it on the road because if you don’t have the inflator on the valve tightly, you may lose gas and not be able to inflate your tire enough. Note that if you have big tires such as mountain bike tires, you may need to use more than one cartridge. Cartridges come in 16 or 25 gram sizes; the former are for road tires and the latter are better for mountain bike tires.
Pump. There are probably hundreds of different bicycle pumps out there. At home you probably already have a floor pump also called a ‘track’ pump. That’s fine for pumping up your tires when you’re at home. But to do a repair on the road you need something smaller and lighter to carry, i.e a frame pump or mini pump. A frame pump is larger and fits on your bike frame neatly between frame tubes. Back in the day that was the only kind of portable pump for bicycles and there were basically two choices, Silca or Zefal. The former are/were legendary particularly when you got one with a Campy head. They came in different sizes to fit different frame sizes. Frame pumps being longer than a mini pump required fewer strokes to fill a tire plus they were quite capable of reaching 90 PSI.
By the way, be very careful if you think you can use a gas station air hose to fill your tire. First, they always have Schrader heads and they are press-on, not screw on. If you have Presta valves, then the only way it will work is if you have a Presta-to-Schrader adaptor. You screw this on your Presta valve (after opening the valve) and a Schrader-headed pump will now fit. They also inject a *lot* of air quickly and the pressure gauges on them may or may not be accurate (usually not). If you do not have the tube completely under the tire (see future post for the details…), you could explode your tube and possibly ruin your tire too making that call for a ride home mandatory.
Nowadays sporting a frame pump is a sure way to advertise what a dinosaur you are because everybody has switched over to mini pumps. Even Silca has a mini pump! They’re much smaller and lighter, so small many can fit in your jersey pocket. The trade off is usually time and arm strength: they require a lot more pumping to fill up a tire because the pump volume is smaller. And some are designed poorly enough that even those with strong arms can’t inflate their tire to more than about 60 PSI. Unfortunately there isn’t a sure-fire way to know which mini pumps are disasters and which are in fact well designed. (Well, except for Silca–its mini pump is near perfect.) Given that you’re not going to using a portable pump very often, the trade-off between small size and low weight for ease of inflation is understandable.
Finally a recent development has been portable battery powered pumps. These little pumps such as by Fumpa or Cycplus have just enough power and battery to get a tire or two up to rideable pressure. They’re quite small and will fit easily in a jersey pocket. The advantage is no hand pumping required and the batteries usually last for more than one inflation cycle. The disadvantage is that once your battery runs dry, you’re done. And obviously you have to recharge the battery once you’re home; if you’re the type who regularly forgets to recharge your cell phone, your bike lights, or your electronic shifters, then maybe a battery powered pump is not a good choice.
Next time: How to replace a tube while on the road.









