How to Repair a Flat Mountain Bike Tire With Disc Brakes

For those avid outdoor extremists, mountain biking can be one of the most rewarding and invigorating sports around.  And if you are like one of us, you like to spend as much time out on the trail as possible.  However, being unprepared and lacking the knowledge on how to make simple repairs can put a damper on your ride as quickly as an unexpected thunderstorm.  And let’s be honest, if you’re out on a trail and the unexpected happens, it’s likely that you will be the only one you have to depend on.  For the rider that has never worked on their bicycle before, we want to prepare you for the most common problem biker’s encounter while on the trail, a flat tire.

Step 1: Identifying Your Tools and Components

In order to learn how to repair a flat tire, one must learn the terminology and components involved.  First we want to familiarize you with the basic tools needed and the bike components you will be working with.   The most basic things you need to have with you are a tube patch kit, a spare tube and a pump.  With the patch kit, you have the option of a kit that uses glue or one that does not.  We will focus this repair using the glue as it tends to last longer, but should you have the glue-less, follow the instructions provided for repairing the tube.  Always have a spare tube and make sure you purchase the right size tube that corresponds with the size of your wheel. 

The last thing you must have is the pump.  When it comes to the pump, the most important thing to know is the type of valve you bike is equipped with.  There are two types of valves, the Presta valve and the Schrader valve.  The Presta valve is a tall, skinny valve in which you twist the top of it to open and close.  The Schrader valve is shorter, sturdier and has a plastic cap at the top that you twist off to remove.  Whichever type of valve you have, your pump will be specific for that type.  If you are not sure or have multiple bikes with different valves, you can opt for a universal pump that will have both size holes on it.  These pumps are small enough to carry with you and can either be strapped onto your bike or placed inside your tool bag.  You should note that some pumps simply push onto your valve while others will need to be screwed.  Tire levers, which help you remove your tire from the rim, are optional as it is possible to complete this task without them. 

The components you will need to know in order to repair your tire are pictured above.

Step 2: Removal of Tire

1.  When you get a flat tire, the first thing you should do is get off your bike and push it to a safe spot so that you are out of the way of other bikers.

2.  Loosen the skewer by flipping out the quick release lever and twisting the cap on the opposite side.  Once the cap is off, you can pull the skewer off, paying careful attention to the direction that the springs are facing.

3.  Front wheel removal - Hold bicycle frame slightly off ground and pull the wheel off of frame (Pictured above).

Back wheel removal - Shift you bike down to the lowest gear then use the steps above to pull off the wheel. You should have enough slack in the chain to easily remove it.

Step 3: Patching the Tube

1.  Now locate your valve.  If you have a Presta valve, you will have to unscrew the nut if it is present.

2.  Pull tire off of rim.  Here is where a tire lever will come in handy if you have one.  Otherwise, you just use your hands to start pulling the tire away from the rim while carefully pulling the valve out also (Pictured above).

3.  Once tire is removed from the rim, you will pull the tube out of the tire (Pictured above).

4.  Next you will want to pump up your tire then feel or listen for the leak.  You do this by placing the hole of the pump onto your valve, after opening it, and then start the pumping motion.

5.  Once the leak is located, you will want to pull out your patch kit and follow the instructions in it.  If the tube is in such bad condition that it is irreparable, you will just need to replace the old tube with the new tube you brought along.

6.  Once patched, you will want to pump the tube back up to verify you have patched the leak correctly. Now you will want to put the tube back into the tire.  Letting a slight amount of air out will make it easier to fit the tube back in. 

7.   If you had to remove a Presta valve nut, you will need to replace the nut before pumping the tire back up.

8.   Pump the tire back up.

Step 4: Reassembly

Front Tire

1.  Lift the bicycle frame slightly off the ground, slide tire between the forks and set the frame back onto the tire.

2.  Slide the skewer back through, paying careful attention to the spring location.  You will want to put the springs back on in the direction you took them off.

3.  With the quick release lever pushed down, screw the cap at the opposite end back on.

Back Wheel

1.   Put the chain back onto the gears and pull back on the derailleur (Pictured above).

2.   Now slide the wheel back between the forks and replace the skewer paying close attention to the spring location. You will want to put the springs back on in the direction you took them off.

3.  With the quick release lever pushed down, screw the cap at the opposite end back on.

4.  Finally, check your tire to make sure there is sufficient amount of air in it. 

Clean up any mess that you made and remember to take your trash with you. You are now ready to get back on the trail.

Step 5: Recommendations

Of course, you should do your best to avoid a situation where you have to patch your tube. The best way is to keep your bike inside, hang it from the ceiling and display it as a decoration piece but for those of you with the mountain biking bug, this is not an option. A more practical way to avoid a busted tube is to simply make sure that your tires have sufficient air pumped into them to avoid having the tube pinched between the ground and your rim. Undoubtedly, accidents will happen but knowing that you can handle one of the most common problems will increase your confidence while on the trail.