Over the last
years, we have been building road bikes and tandems with
700c, 650c, and 26 inch wheels. A 26 inch, or a 650c wheel is about 1 inch
smaller (about 2 inches smaller with road slicks) in diameter than a 700c. On smaller
bikes, that 2 inches sometimes allows us to build the bicycle to the perfect size for the
Customer without sacrificing performance. 26 inch wheels are not exclusively for
small bikes though, I am 6 feet tall and I ride both a racing bike and a tandem with
26 inch wheels.
Often, a customer will ask for the larger size wheels, even when the smaller wheels
would allow us to build the bicycle to a more optimum geometry. It seems that some
people believe that larger wheels mean faster wheels. Some people think that because
700c wheels are the 'standard' for road bikes, they must be better.
In our shop we've been building bikes for over 30 years. Over this
time, we've seen the rise and fall of many standards; Down tube shifters, center
pull brakes, U-brakes, Suntour componentry, dual articulation derailleurs, side pull
brakes and 27 inch wheels just to name few. These features were 'must haves' in their day. A sales person wouldn't dream of even showing a new bike to a customer unless it had at least some of these features. But now, one would have to search to the ends of the earth to
find a current, 1998 model, high quality bike offering any of these features. These features
were standards in their time but gave way to either newer technology, or, in some
cases, the standard fell back to the predecessor. In any case, the standards took
a long time to change.
One standard that has more or less held for the last decade are wheel sizes. The 'standard'
road bike has 700c (the successor to 27") wheels. The 'standard' mountain bike has
26 inch wheels (inherited from the old balloon tire cruiser). It seems that many
people make a connection that goes something like this......
"Mountain bikes are slower than road bikes, and mountain bikes have smaller wheels,
therefore, 'smaller' wheels equal 'slower' bikes, at least on the road,"
Using this same logic, we could assume that a monster truck is faster than a Porsche,
or a School bus is capable of higher speed than a Jaguar E-type. Do these assumptions
sound ridiculous to you? If not. I've got a swamp I'd like to sell you.
The engine in the monster truck is more powerful than the Porsche's engine. The wheels
are certainly larger (2 to 3 times larger). What makes the Porsche faster than a
monster truck? For one thing the Porsche is lighter. It is designed with more responsive handling. But most of all it has gears that will accelerate the car to higher speeds
even with the smaller wheels. Can the same be true with a bicycle? The answer Is
yes. Road bicycles, regardless of their wheel size, are designed lighter, more responsive, and they are geared for the road.
Wheel size has nothing to do with the speed of a bicycle on the road. A road bike,
or tandem bike With 26 inch wheels is geared to travel at the same speed as a bike
with 700c wheels. The answer lies in gear inches. Gear inches is a means of measuring
the relative number of inches traveled forward per crank revolution. The higher the 'gear
inches' the more distance traveled per crank revolution. A road racing bicycle in
its fastest gear, is usually geared to about 110 'gear inches'. This is true no matter
what size the wheels are. My road bicycle has 26 inch wheels, and my top gear is 112
inches. If I have a 112 inch gear, and I'm pedaling at a cadence of 90 revolutions
per minute, I will be traveling forward at about 31 miles per hour no matter how
big my wheels are....same cadence, same effort, same calories burned, same panting and wheezing,
no more or no less fun.
Below are a few standard gearing patterns that are used for 700c and 26 inch road
wheels;
700c wheel 52/39 X 12-24 (116 inches high gear) (43 inches low gear)
26 inch wheel 54/40 X 11-23 (122 inches high gear) (43 inches low gear)