Bicycle Tubes & Air Pressure

Replacing bicycle tubes and checking your air pressure are two things that are part of the routine maintenance on your bicycle.  For novice or recreational cyclist the type of tube you need can be confusing and proper air pressure is sometimes over looked (even for experienced cyclists). 

      

                  

I’ll first discuss the different types of bicycle tubes.  Pictured above are both Schrader and Presta valve types.  The Schrader valve you will recognize as your standard tube valve.  This is the same type of valve that you will find of your automobile and you will also find this valve type on many bicycles.  This type of valve can be inflated with any standard bicycle foot pump and most pumps at your average auto service station.  Most recreational and many mountain bikes have this type of valve.   The second valve pictured above is a Presta valve.  This type of valve is also sometimes referred to as a French valve.  The Presta valve is often found of road bikes and higher-end mountain bikes.  Presta valves are more slender than the Schrader valve and, therefore require a smaller hole in the bike rim.  The valve hole in the bike rim is the weakest point of the rim.  Road bike wheels are usually very narrow and a bigger hole means a weaker rim.  The Presta was developed specifically for bicycles and they require a special type of air pump that is suited for Presta valves.  

Once you determine what type of tube valve you need, you will then need to determine what size tube your bike requires.  This is fairly simple as most bicycle tires have the size of the tire printed on the side.  Simply locate the size of the tire and look for a tube that matches that size.  Tubes are usually made to cover a range of different sizes.  For example: A bicycle with a tire size of 26x2.1 could use a tube that covers 26x1.75-2.125 or a tube that covers 26x2.1-2.3  As long as your tire size falls within the range, the tube is acceptable.  Standard Presta and Schrader valve tubes usually cost somewhere in the $5 to $10 range with some specialty tubes costing a little more.

Proper air pressure is a very important factor that is often overlooked.  Even though it might seem like a small, minor detail, improper air pressure can be costly and possibly even dangerous.  As with tire size, the proper air pressure is usually printed on the side of the tire.  Again, this is usually a range and not an exact number.   Mountain bikes, for example, usually have a range somewhere around 45-65 pounds per square inch (psi) whereas road bikes are usually much higher and range somewhere around 100-120 psi.  The manufacturer prints this pressure range on the side of the tire for a reason.  This is the range where the tire will perform at its best and will be safe for the rider.  An over inflated tire could lead to poor traction and poor handling (and possibly popping a tire) and under inflated tires may lead to pinch flats (where the tube gets pinched between the rim and the tire due to under-inflation) and may cause the tire bead to come loose.  To be safe, a cyclist should check the air pressure of a tire before every ride.  This is especially true for the recreational rider who may not ride on a regular basis and the bike is in your garage for an extended period of time between rides.  All tubes will lose air over time.  The longer the amount of time, the more likely it is that you will need to inflate your tires.  We highly recommend that you get a bike pump with a built in pressure gauge.  Most pumps designed specifically for bicycles not only come with a pressure gauge, but also have the ability to inflate both Schrader and Presta valves.  These pumps usually cost somewhere in the range of $30 to $60.  Topeak and Park Tool are two of the brand names of bicycle pumps we carry at Country Squirrel Outfitters.  Park Tool is the pump of choice for our repair shop and at home.  A good bicycle pump can also be rebuilt when parts begin to wear out.  Manufacturers of these pumps offer rebuild kits and replacement parts so you don’t have to replace your entire pump.  A good pump will last for many, many years.