Q: Why should I use a bike computer?
A: A bike computer can make riding more pleasurable. Even the most inexpensive computer will tell you how far you
have pedaled and how fast you are going. The more sophisticated models will help you pedal faster and further
with less effort and greater pleasure.
Q: How will a bike computer make my riding easier and more pleasurable?
A: A computer can make your riding easier because it quantifies your workout. It allows you to judge whether your
average speed, maximum speed and trip distance are increasing or decreasing as the days and weeks go past. Bike computers
with cadence (pedal revolutions per minute) can help you spin faster and exercise more efficently. As you become more fit
you will feel better; the pleasure you derive from cycling will increase.
Q: What is cadence?
A: Cadence is a measurement of how many complete revolutions your pedal makes in one minute. One revolution
would be when your right hand pedal starts at the 12 o'clock position, passes through 3 o'clock, 6 o'clock, 9 o'clock and
back to 12 o'clock.
Q: Why is cadence important?
A: Cadence allows you to achieve your greatest bio-mechanical efficiency. It is easier for your legs to be
smoothly spinning 60 rpm's than grinding away at only 20 or less rpm's. Professional riders, especially road bikers, can
smoothly spin at 90 or more rpm's.
Q: How does understanding cadence help me choose what gear to be in?
A: The primary reason that a quality bicycle has so many gears is so that you may ride efficiently over almost
any terrain. Ideally, you want to maintain a high cadence. 60 rpm's is a good place to start. Choose your gears so you are
spinning 60 rpm's or more at the speed you wish to be going. As you ride more, your rpm's should increase and your style
will become smoother.
Q: I have a mountain and a road bike. Should I share a computer between them?
A: Yes, you should. You will save money by buying just one computer. One computer is easier to get use to than two
and requires less maintenance. Your cumulative distance will always be instantly accessible. The best Sigma Sport computer
has two separate odometers for cumulative distance; one for bike 1 and another for bike 2. For total distance it adds
bike 1 and bike cumulative distances. One top quality computer will serve you better than two mediocre
computers.
Q :What about wireless computers. Are they reliable?
A: Wireless computers have several advantages and a few disadvantages. On a mountain or cycle cross bike,
eliminating the wires is almost a necessity. If you do not remove the wires, tree branches and bushes may do it for you!
Wireless mounting also lends a cleaner appearance to your bicycle. Older wireless computers were finicky. However both
the Cateye and Sigma Sport current wireless computers are excellent. All of the Sigma Sport computers can be easily
upgraded to wireless operation at any time by just purchasing their RCS Wireless kit. The disadvantage of wireless mounting
is that it requires a front wheel mount. Most indoor trainers only spin the rear wheel; hence a rear wheel pickup is
required with their use. Some wireles mounts do not allow you to use cadence either.
Wireless computers require a transmitter that must be mounted in a direct line with the computer head and within a pre-set distance. The transmitter must be connected to the front fork. We do not reccommend using the wireless computers for motorized applications.
Q: Why must I program in my wheel size?
A:It is critical that you program in the exact circumference of your wheel. The computer head depends upon this information to calculate speed and distance. Most of the computers we sell will accept a wheel circumference setting in one mm increments for exceptionally precise speed and distance calculations.
Q: Is wheel circumference that 3 or 4 digit number that I must program into my computer evey time I change the batteries?
A: Yes. That 3 or 4 digit number represents the exact circumference of your wheel in centimeters (3 digit) or millimeters if it is a 4 digit number. This number MUST be entered in millimeters or centimeters; inches will NOT work.
Q: What is the relationship between circumference and diameter?
A: Circumference divided by pi(3.14) equals diameter. A wheel with a circumference of 112 cm will have a diameter of 35.6 cm. The math is: 112 cm divided by 3.14 = 35.6 cm.
Q: What wheel sizes will bike computers accept?
A: Cateye computers will generally accept wheel circumferences from 112 cm to 255 cm. Put another way, that represents wheels from 14 inches (35 cm) to 32 inches (81 cm) in diameter. Sigma Sport and Topeak computers will accept a wheel size from 1 to 50 inches ( 2.5 cm to 127 cm) in diameter. Topeak and the Sigma Sport BC600, 800, 1200 and Targa all use the more precise 4 digit, wheel setting numbers.
Q: What is the best way to measure wheel circumference?
A: The most precise method is to use a 6 foot (2 meters) piece of single strand, 16 to 20 gauge wire. Bend a small "L" on one end and then tape that end to the center of your tire's tread. Be sure to bring your tires up to the normal pressure that you ride with first. Then, lay the wire lengthwise along the outside of your tire's tread and use electrical tape to hold it in place. When you come back around to your starting point, bend another "L" in the wire. Now carefully remove the wire and precisely measure it. This measurement will be the exact circumference of your wheel.
Different width, brands and types of tires will have different circumferences. If you race on one set of wheels and train on another we reccommend precisely measuring both sets. If the circumference difference is more than 5% we suggest using a computer that allows for two wheel settings. Your speed and distance readings will be more precise and make more sense.
Q: How does a bike computer work?
A:All bike computers have a sensor and a magnet assembly. The magnet mounts on a front or rear wheel and must pass by the sensor once for every revolution of the wheel. When the magnet passes by the sensor a small electrical charge is produced and sent to the computer head. The head then knows how many complete revolutions your wheel has made. Since you programmed in the exact circumference of your wheel earlier, the computer knows that you have traveled that distance for every wheel revolution. Now distance is simple to calculate. Since all computers also record time it is easy to calculate miles per hour, average speed, etc.
Q: Can I use a bike computer on my motorcycle or racing kart?
A: Sure. Topeak and Sigma Sport computers will accept a wheel size from 1 to 50 inches (2.5 cm to 127 cm) in diameter. Both brands of computers will record up to 99,999 miles and speeds up to 183 miles per hour. The Sigma Sport 800 is a favorite for motorcycle and kart racing. We suggest purchasing the longer wire, rear wheel mounting kit, so you do not have to splice wires. The sticky backed magnet with a zip tie is a good choice too and will fit almost any application. You can also use a Topeak or Sigma Sport computer for construction equipment, farm tractors, lawn mowers and virtually anything with a wheel. Sigma Sport's optional cadence function is ideal for applications that require a constant read out of RPMs.
Q: Can I splice the wires on a computer wheel kit? Is their a critical length past which the computer will not function properly?
A: You can splice the wires on the computer wheel kits that we carry. Splice and solder one wire at a time so any polarity is maintained. We have added up to 4 feet (1.3 meters) of wire to a 3 foot (1 meter) kit, without any adverse effects. We use 18 to 20 gauge twin lead speaker wire and rosin core solder. To finish, we tape the joints with vinyl electrical tape.
Q: Why does the speed reading top out at 70 miles per hour on my motorcycle?
A: Everytime the wheel magnet goes past the fork mounted pickup sensor a small pulse of electricity is created. At high wheel RPMs it is possible for the pulses to merge resulting in a steady speed readout. Increasing the gap between the wheel magnet and sensor solves this problem.
Q: Which computers have the largest numbers for speed readings in miles or kilometers per hour? I need to know the exact height of the numbers.
A: The Cateye Velo 2, Mity 3 and Enduro 2 have the tallest numbers at 12.5 mm. The Cateye Astrale is next at 10 mm. All of the Sigma Sport computers have 9 mm tall, speed numbers..
Q: I do not have traditional spoked wheels. What can I do?
A: All bike computers require a magnet to be placed somewhere on the front or rear wheel.
Just about any magnet will do. We carry ones for traditionally spoked wheels, radially spoked wheels and even
carbon spoked wheels like Spinergy. In a pinch, on a race day, we have even cut up and used common refrigerator
magnets!
The stronger the magnet, the wider the gap between the magnet and sensor can be. Usually the gap is 1 to 2 mm.
Q: I lost my computer manual. Do you have replacements?
A: Yes. We have copies of original manuals for old and new Sigma Sport computers. They are listed under the Sigma Sport accessories. Unfortunately we cannot get paper copies of Shimano or Cateye manuals. However you may download Sigma Sport and Cateye computer manuals from their respective sites. Follow the links from our Cateye and Sigma Sport pages.
Q: How often should batteries be replaced?
A: Batteries will generally last 1 to 2 years. We reccommend replacing them every spring as a precautionary
measure. Otherwise you may unexpectedly lose all your stored information in the middle of the summer.
Q: Will I lose my cumulative mileage and wheel setting information when I change the batteries?
A: Yes, you usually will. However the better computers will allow you to reprogram your cumulative mileage and wheel
setting information back into memory. Always keep the instructions that come with your computer. Write down what
wheel setting you initially used. Also record your cumulative mileage before you change the batteries.
Q: Where can I get batteries and spare parts?
A: We carry the correct batteries for all of the computers we sell and several other brands. It is best to
have the battery in hand when you call us. If we do not carry your computer we will need to know the number on your
battery. We also carry a complete stock of small parts and accessories.
Q: What if my computer needs repairing?
A: All of the computers we sell are covered by solid manufacturers warranties. All have expert
repair facilities in the United States. If your computer is under warranty, they will usually fix or replace it for no
charge. If it is out of warranty, there may be a small charge. You may call them direct or send your computer to us.
We will forward it to them, get it taken care of and return it to you. A small handling fee and freight charges will
apply.
Q: How can I contact an official warranty center?
A: Call Cateye at 1-800-522-8393, Campagnolo at (760)931-0106, Shimano at 800-423-2420, Topeak at 800-213-4561 or Sigma Sport at 1-888-744-6277. They can assist you with problems or questions. Please feel free to call us as well particularly
if you run into problems.
