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Course Measurement and Certification Procedures

Use of the Calibrated Bicycle

Mounting the Jones Counter on Your Bicycle

Note: These mounting instructions apply to the current model of the Jones Counter, known as the “Jones Counter model JR.” This information is also available at

The JR counter will fit on most bicycles without modification. Remove the wheel from the bicycle and slip the counter over the axle on the LEFT side. Put the wheel back on the bicycle with the counter between the fork and the wheel. Tighten the wheel securing nut or lever.

Counter mounted on bicycle
Counter mounted on bicycle

Caution: Important – Do not attempt to rotate the wheel or ride the bicycle until you have checked for proper clearance. You may damage the counter.

Wiggle the wheel back and forth just a little. If the large counter gear rubs against the fork, the fit is not correct. This can be sometimes be corrected by installing a washer between the outer side of the counter and the inside of the fork. Try this. If free rotation without rubbing cannot be obtained, the counter cannot be used on your bicycle.

Check for clearance before rotating wheel
Check for clearance before rotating wheel

If there is interference between the small plastic gear and the spokes, install a washer between the inside of the counter and the adjusting nut on the wheel.

If you are unable to fit the counter to the bicycle using washers, it may not be possible to use the counter on the bike.

The counter is driven by a small metal projection (tang) on the inside of the large gear. This should reach between two spokes, which will cause it to rotate. If the tang is not long enough, slip the provided electrical connector over the tang to make it longer. The tang may also be wired to a spoke using the small hole provided on the tang.

Use electrical connector extension to tang if needed
Use electrical connector extension to tang if needed

Once the counter is properly installed, and no interference is present, you can safely ride the bicycle and obtain proper counter operation.

Again – before attempting to rotate the wheel, check for interference. If you do not do this you may damage the counter.

Riding Technique

Ride in a relaxed manner, in as straight a line as possible. The basic idea behind the method is that a small amount of "wobble" while riding the course is accounted for when calibrating the bicycle. Ride the calibration course the same way you will ride the race course.

Avoid braking with the front wheel. When you brake, apply the rear wheel brake.

Failure to ride in a straight line, particularly when diagonally crossing a street, may yield a short course. Rather than watching the ground near the front wheel, aim for a distant point. Locate a point in a direct line to where you need to ride. Then ride toward that point, keeping an eye on that point.

When you encounter potholes or bad bumps, do not swerve to avoid them. Minor ones can be negotiated by slowing down and getting up off the bicycle seat. For a bad bump or hole, stop and carefully walk the bike through it. When you have to get off the bicycle and walk it (e.g., when attempting to reach an exact count or when going through a pothole), you will add roughly 1% to that portion of the course unless you push down on the handlebars to keep some weight pressing down on the front wheel.

Tires should not be checked for pressure at any time between calibration and recalibration. This causes a small air loss which may significantly alter your riding constant.

Avoid extreme weather conditions. Do not measure on very windy days.

Reading the Counter

Freeze the front wheel before reading the counter. This may be done by hand or by using the front wheel brake.

When reading the counter after backing up, be sure to move the bicycle forward again before taking a reading to avoid a "backlash" effect.

If you go past a count at a kilometer/mile marker, it is best to make a mark where you happen to stop, record the count there, and later adjust the split point by measuring backwards with a tape. Although it is possible to wheel the bicycle backwards, this should be avoided.


When measuring, you may encounter runners, other cyclists, or just people enjoying the out-of-doors. Slow down. Politely explain that you are measuring a race course and have to go in a straight line. They will usually yield to you. Except in extreme cases, avoid moving out of someone's way. If necessary, stop and wait for that person to go around you. Please be courteous at all times. You can minimize such problems by measuring when traffic of all sorts is at a minimum.

If you do a lot of measuring, you may wish to carry fore and aft signs reading "Official Measuring" in yellow lettering on a dark background.

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