• Minori Sanchiz-Fung

Flat Fix, Flat Fix!🗣

Of course nobody wants to end up stranded with a flat tire.. knowing how to properly replace a tube on the fly can be a critical skill to help keep yourself and your fellow riders rolling.

Feel yourself bouncing a bit on each pedal stroke, or like there's a bit of lag when you're banking into a turn? Careful now, you just might have a flat!

Not to worry - with the appropriate repair equipment and an understanding of the task at hand - a swift return to the open road (or trail) is all but guaranteed.

The traditional tire system consists of a rim, a rim strip, a tube, and a tire. A "flat" indicates that the tube is no longer holding air. You'll want to identify the source of the puncture before we replace and inflate the new tube - else you might end up stranded with another punctured tube.


  • Extra tube - Be sure you pack the correct tube size. They come in a range of diameters and widths and should correspond to your tire size (printed on the sidewall).

  • Levers - We like Pedro’s levers, as they are durable, stiff and come in pairs.

  • Multi-tool - In some cases, a tool is not required. However, you may have a bolt-on wheel or thru-axle system, which requires a tool to install/remove (ex. 15mm wrench, 5mm or 6mm allen wrench).

  • Inflation - You will need some form of inflation, whether that be a frame pump or C02 chuck.

C02 cartridges

  • Pros: can fit into a saddle bag, small, lightweight, fast inflation

  • Cons: minimal room for user error as it is a one time use, no gauge

Frame pump:

  • Pros: can be used multiple times to seat and reseat tires. Some models have pressure gauges to inflate precisely to recommended psi.

  • Cons: can be quite a workout to get to the appropriate psi, can be heavy and have mounting limitations with certain frames



You may need to release the brakes before attempting to remove the wheel. This will allow you to free the wheel from the frame using the quick release skewer. Again, don't forget to pack your tool if you have a bolt-on wheel or thru-axle system. If removing a rear wheel, shifting to the smallest cog will make it easier as the derailleur can get in the way otherwise.

More info regarding the removal of wheels can be found in this video here.

TIRE & Tube

Grab your tire levers and sneak them just under the tire bead approximately 5-6 inches apart. You'll be trying to lift the bead over the rim - sometimes locking one lever onto a spoke can help. Make your way around the rim, freeing one side of the tire and exposing the tube inside. Before removing the tube fully, make note of the orientation of the valve in relation to the tire (you can use branding etc to do so). Since you will want to identify the cause of the flat, you will need to locate the puncture in the tube and follow it to the source whether that be within the rim of the wheel or the tire itself.


Once you have the punctured tube removed, the best scenario is being able to inflate it slightly to locate where the tube is losing air. The most common cause of a flat is a “pinch flat” and tends to look like 2 symmetrical holes on the inner side of the tube that faces the rim. These types of flats are often caused by low tire pressure, resulting in the tube being pinched between the road and the rim of the bike during a bump in the road. The best way to prevent a pinch flat is to inflate your tires to the appropriate pressure (printed on the side of each tire) at least once a week and check before each ride.

It is always best practice to check the rim strip (cloth tape, rubber, or vinyl strip that lines the rim) to ensure that it covers the spoke nipples and is still intact. If this has folded over, broken, or slid off to one side, the exposed edge of the hole/nipple can cause a puncture on the inside of the tube when it is inflated.

If the puncture in the tube is located on the outer side of the tube, this is indicative that an object has made its way through the tire. It is crucial to locate and remove before installing a new tube as it could still be embedded in the tire and immediately cut the new tube when re-inflating. The best method is to turn the tire inside out to visually and physically inspect for glass, wire, thorns etc. Once you have removed the foreign object from the tire, aligned the rim strip, and reinspected the tire, you can proceed with installing the new tube.

If no hole can be located in the old tube. Sometimes an abrasion can cause a slow leak without a clear puncture or the valve has been damaged.


Ensure you have right size tube (the tires will be labeled on the sidewall and the tube size will be a range with which the tire size needs to correspond)

Inflate the tube slightly - this will make it easier to install without it getting pinched in an unfortunate position.

As you go to inflate fully, make sure the bead of the tire is seated as well as possible. If you notice any issues as you inflate, quickly stop and let out any air, adjust the tire, and try again.


Install the wheel back on the bike (if it is a rear, being in the smallest cogs will make it easier) and re-attach or close your brake’s quick release.

Proper wheel installation is crucial for ensuring safety, so be sure to check out the previously linked video if you have any concerns.

Always give it a good spin and check to be sure the wheel is straight in the dropouts, there is no rubbing on the frame or brake rub. When reinstalling a rear wheel, give the pedals a spin to re-engage the chain with the cogs before laying down the power - just in case it’s between gears.

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