Where and How to pin your number
Pin your number so that the race officials can read the numbers as you cross finish line. Note photos to see location that provides visible number placement verses placement where number is not legible.
Why do officials obsess about number and folded numbers? The number needs the white background in the correct position to be easily readable. If the white background has been folded down to a narrow border, or crumpled it fools the eye and the number blends into the writing on the riders' jersey making it virtually unreadable. As well, the eye becomes "trained" to see an object of a specific size. When that size changes, the eye keeps searching trying to locate the number. You will eventually read it but you will have missed the next two or three numbers.
Where to Pin Your Number
As you look at the following pictures, you can see that as a number gets closer to your back, it becomes more difficult to read, and as numbers get lower on the side, they become easier to read.
A good reference for number placement is the side panel of your jersey. Start at the front edge of the side panel, about 2 inches from the armpit seam. Put a pin in the number, and then tilt the number based on your riding style.
This will make sure the number is low enough to be seen from the side, but not so low that a camera positioned above couldn't see it. Rider number 125 (top-right) in above photo is a good example of this.
Photo Finish "What is the Number of the third place rider?"
How to pin your number
To pin on numbers, you should not use the provided holes. Instead, we want to "flat-pin" the number. Pull the jersey away from the rider's body. Push the safety pin into the number and jersey. Once through the jersey, insert the pin about another 3/4 of an inch, then push the point out through the jersey and number. You can now close the safety pin. This technique has multiple benefits. As mentioned above, this technique will not snag or tear the number or jersey. Also, each pin does 2 pinnings of the number, once as it goes into the jersey, and a second pinning, as it exits the jersey. And finally, the number will not flap when pinned in this manner.
A reminder to your buddy that is pinning on your number, that he will need to pull the jersey away from the skin while inserting the pins. This does the following: 1) It prevents you from getting stabbed by the pins, and 2) you do not want the pins to pass through any undershirt that you might have on, under your jersey. The last thing you want to find out during an urgent trip to the bathroom before your race starts, it that you cannot get your skinsuit off, because it is pinned to your undershirt.
Minimally, 4 to 6 pins should be used. For larger numbers, use 8 pins, one in each corner, and one in the middle of each side. Although this may seem like a lot of pins, it is not. Use enough pins to make sure that the number is securely fastened and will not flap in the wind. Some riders try to position their number in a location where they think it is most aerodynamic. This doesn't really work well. Instead of putting the number in an odd location, put it in the correct location, and use enough pins to prevent the number from flapping. Using the appropriate number of pins will prevent the number from flapping or being a source of wind drag. At every race you go to, you have access to safety pins. Always save your safety pins at the end of the day, creating a stash of pins to keep with your race gear.
At some events, such as cyclocross or road nationals, you may also be given smaller numbers. Find out from the technical guide for the event where the smaller number should go. For cyclocross it is common for this smaller number to go on your left bicep, to be view by the announcer and officials. For road events, these extra numbers are usually put on the shoulder blades. Even though these are smaller numbers, they too, should get 4 to 6 pins in them.
Incorrect, Wrong, don't do it this way - Pin of number to jersey
Correct way to Pin your number
Pinning a number like this has multiple problems. First, it does not hold the number tight against your jersey, allowing it to flap like a sail (see pictures below). Next, the Tyvek can get caught in the spiral of the pin, and the jersey fabric can get caught in the head of the safety pin. Both options cause potential tearing and snagging of the number or jersey.
Crumpled v. Un-Crumpled Numbers
Crumpled v. Un-Crumpled Numbers
There is a small group of riders that, for some reason, believes that there is a benefit to crumpling a Tyvek number. Usually the claim is that the number lies flatter, or is more aerodynamic. Crumpling a Tyvek number has several disadvantages:
It is harder to be read by the officials and finish line camera (see photos below).
A crumpled number has more edges, and therefore more wind drag than a non-crumpled number.
Flat-pinning a number allows it to be as close to the jersey as possible, as opposed to a number with multiple folds, which forces the number away from the jersey.
Finally, it is illegal to fold your number (see rules listed below). Of course it is a rule that typically is not enforced, and there is a distinction between a wrinkled number .vs. a crumpled number. ( After all, just wearing a number will give it wrinkles !).
Example 1: These 2 riders are in the same field, on the same lap. The number on the left is not crumpled, the number on the right, is crumpled. Which one is easier to read?
Example 2: These two teammates are riding together in the same sunlight. The number on the left is crumpled; the number on the right is not. Which one is easier to read?
The Rules on Numbers
1N7. Racing numbers.
(a) Racing numbers are provided by the organizer, who may require a deposit that shall be refunded on return of the numbers in good order. The figures shall not be hand written, but printed in block letters using black waterproof ink.
Numbers shall be constructed from materials sufficiently durable to last the race without tearing or disintegrating, even in adverse weather. The name of the race or race sponsor may appear on a competitor's number. Promoters who fail to provide numbers meeting the above requirements to all riders shall be fined as specified in the Schedule of Fees.
(b) Riders shall place their numbers as prescribed by the officials and in such a way that they are visible when the rider is in a racing position. When shoulder numbers are provided for cyclocross, they are worn on the upper arm to be visible from the front.
Hip numbers shall be attached securely at least at the four corners with pins and no accessory or hair may obstruct a clear view of the number (riders with misplaced, obscured or unreadable numbers will not be placed).
If shoulder or frame numbers are provided, they too shall be placed as prescribed. Numbers may not be folded, trimmed, crumpled, or otherwise defaced. [Replacement of the numbers at riders' expense if noted before the start, otherwise warning or relegation.]
(c) An administrator may impose additional number requirements.
Thank you to KEN & CINDI HART at Planet Cycling for compiling this tutorial.