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ATTACHMENT 1
Bicycle adjustments^2,10,11,12

ADJUSTMENT

SPORT/TOURING, RACING, HYBRID BIKES

MOUNTAIN BIKES

Saddle Height - If you are a long-time cyclist, changes to saddle height should be in small increments, like ¼", and left there while you adapt to the change prior to making further adjustments.

Once you get the seat adjusted to a comfortable height, mark the seat. The seat post will slowly sink into the tube over time, so occasionally check and readjust it to the height that is best for you.

Wear the shoes and padded shorts you plan to wear for cycling and sit on the bicycle supported on a wind trainer or other vertical support. Place your heels on the pedals (bottom of the pedals, if you have clips on the top) and pedal backward. When the crank arm is parallel to the seat tube, usually just after bottom dead center, the knee should have a slight bend. When the leg is at its most lengthened position, it should maintain about a 10° bend.^1,12 The knee should never be straight to avoid overextension and you should never have to rock your hips side to side while you pedal. Some authorities suggest a bend of 25° ^13,1, but too low a seat presents danger to the kneecap when the leg is at the top of the cycle In fact, having the seat too low is the most common cause of patellar (kneecap) problems.

Mountain bike seat height is usually set lower to keep the center of gravity lower and to allow for greater stability and maneuverability1. And mountain bikers spend a lot of time out of the saddle going over bumps¹³, so they need to be able to stand on the pedals without interference of the saddle. Adjust the seat so it is 2" to 6" lower than the adjustment determined for the other types of bicycles.

The saddle should be level or tilted slightly higher in the front. Place a carpenter's level along the length of the saddle to evaluate the amount of tilt. Tilting the saddle forward will cause the rider to constantly slide forward, bracing themselves with their arms and causing stress on the arms, wrists, and hands. However, tilting the seat forward is sometimes recommended to increase spinal curvature, forward tilt of the pelvis, and to relieve pressure on the crotch (primarily for women)¹

Same as for the other types of bikes.

The saddle can slide forward and backward. This needs to be adjusted so that the knee is not too far forward on the downward stroke of pedaling. If the knee is flexed too much, it will cause pressure on the kneecap. To adjust, sit on the bicycle and pedal until the crank is at the most forward (9 o'clock) position. Hold a straight edge or plumb-line on the center front of your kneecap and extended down to the crank arm. The line should be perpendicular to the floor. Adjust the seat forward or aft until the line is perpendicular.

Same as for the other types of bikes.

This is the most variable adjustment made. To fit the cyclists "reach", place hands in the dropped position on the curved part of the handlebars and drop a plumb line from the nose to the handlebars. This should bisect the handlebars in the center at the stem. In this position, the back should be slightly lower than a 45° angle and should have no sharp bends. An overextended position places more stress on the lower back and hamstrings. A cramped position inhibits breathing.

Handlebar height should be at least 1-2" lower than the seat for a short cyclist and up to 4" lower that the seat for a tall cyclist. Handlebars that are too low may cause hand numbness and tingling.

Handlebar width should match the width of the rider's shoulders. Handlebars that are too narrow restrict breathing.

The bottom of the handlebars should be level or tilted slightly backward toward the middle of the rear wheel.

Mountain bikes and hybrid bikes are generally more upright. Make sure you buy a bike with a handlebar stem that will accommodate your needs. A good upper-body position will allow you to sit comfortably on the bike with your arms relaxed and your elbows slightly bent. You should not feel cramped and your elbows should not interfere with knee motions. In general, handlebars should be 1-2" below the seat height, but this is a very individual choice.

Wide handlebars are used for slow speed control. Narrow handlebars are used for quicker maneuvering through wooded trails.

Same as for the other types of bikes.

Same as for the other types of bikes.