Bike Size?

What bike size do I need?  This is a crucial question when considering purchasing a new bike.  If we are getting a new type of bike, have experienced changes in height or weight, or will be using our new bike in a different environment, we will do well to check on the bike size we need.

Asking, “what bike size do I need?” should be one of the primary questions we ask in order to ensure the most bang for our buck.  The correct size goes a long way in ensuring riding comfort.  As is true with most items that require good fit, a bike that complements our sizing will be efficient, thus making it a utility that will do what it promises.

At the heart of size is the ability to answer the question of measurements.  While bicycle charts for different types of bikes and riders are available at our disposal, especially on the internet or at bicycle shops.  However, the measurement principle is quick and simple to understand without having to carry charts around with us.

We will need to know the rider’s leg inseam, torso length and arm length.  The leg inseam is the measurement from the crotch to the foot.  The leg inseam, or the “stand-over height”, is the one that is most referred to.  Add 1-2 inches to the leg inseam measurement allows for comfortable clearance of the bicycle’s top tube.  Some sources recommend 2-4 inches if considering a mountain or commuter bicycles.  Please note that if the bicycle does not have a top tube (but has a step-through frame), we will not need to consider the leg inseam measurement.  Since the lowered top tube allows for a step through, we will no longer need to ensure step-over clearance.

Torso length is the measurement from the crotch or the sternum while the arm length is the measurement from the end of the collarbone to the middle of the closed fist.  The sum of torso length and arm length divided by two, minus six provides the ideal distance between seat and handlebars. [ (torso length + arm length)/ 2 = x.  x – 6 = reach distance].  This calculates the reach distance for the rider.

Setting measurements aside, there are other important basics to consider.  Bicycle frame, for example, helps to maximize power.  A fit too small will not allow full leg extension by cycle or pedal power.  A fit too large, on the other hand, will not allow for full drive from leg rotation.  Rider should stand over the frame with both feet on the ground and allow about 2 inches of clearance.

Seat position is up to rider preference, as long as the rider’s feet can rest on the pedals through the full rotation.  At the furthest rotation, the legs must remain fully extended while the feet rest flat on the pedal.  The rider’s hips should not see a side-to-side movement when the rider is pedaling.

Often the forgotten checkpoint, incorrectly fitted handlebars can cause serious injury like back pain, shoulder strain, and wrist soreness.  Depending on whether the rider likes to ride high or low, upright or forward, handlebars should not extend beyond the manufacturer’s recommendation.

Lastly, find the best fit through trial and error.  Common sense and feel will rule out the obvious misfits.  Whatever our shopping style, one thing is certain:  Before you hand the hard-earned dollars, take our new bike out for a spin.  Good luck!

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