Last month we visited the issues of availability in the quest for the right bike. Agree with the concept or not, the chances of purchasing your next bike or frame based solely on the size and geometry of the model are high. Both can be based on the dimensions of your current bike or ones established between you and your fitter. This month we will look at my clients’ number one question, “What is my size?”
Most cyclists can ride two different sizes of the same model, comparable to a car available in a coupe or sedan. While basically the same on a bicycle their characteristics or personalities are slightly different due to the wheelbase of the two models affected by the different proportions based on rider weight. So how much you lean over impacts the weight distribution and ride quality of the bike.
Matching the basic geometric shapes of the rider and bike are of utmost desire as a fundamentally more sound marriage is achieved. In order to do this you need to look at your body as a basic geometric shape, the lean angles, or type of riding you do. Now think of the bike frame as similar but proportionally growing from size to size, but in what shape? Is it solely accountable for the range of which the saddle and handlebar can be placed? Is it square or a rectangle?
In looking at the human body its vast array of differences boil down to basics:
Frogs: Legs longer than the torso, both male and female.
Purchasing a bike solely on stand over height/inseam often produces a bike too large. Top tube, head-tube and seat tube angles should be top considerations in the decision process. Males should consider their arms' wingspan in consideration of size, as long arms need a home and that home is usually the next size up. Due to the shorter torso a shorter cockpit can be obtained, but you need to be honest about your flexibility as the short cockpit often produces a low cockpit. Female riders will no doubt gravitate towards women’s specific models which in most cases are a vertical rectangle. The challenge is that most women’s models have steep seat tube angles, putting your knees too far forward due to longer femurs. Clients uncomfortable in this situation, where they need to be further back but want a higher and shorter position, need an upside down triangle. This typically eliminates many women’s models from consideration.
Weenie Dogs: Long torso, short inseam.
Often many in this proportion, having previously purchased based on stand over height, have been on a bike too small for years. And while cliché, it affects about 50% of males. Since the majority of most bikes are proportionally square it stands to reason that historically long stems (or yoga) were needed. If you were to go a size up for the longer top tube it was often at the expense of stand over height and your voice a few octaves higher than normal. Here a horizontal rectangle is in order to accommodate the extra length of the longer back. Flexibility will still come into play in regard to head-tube length as the majority of these models with the long top tubes are low “race” models. In recent years many modern sloping models have offered the best of both worlds with variable front end heights and ample stand-over to accommodate this shape and the fleeting flexibility of an ever graying peloton.
Apes: Short inseam, long torso and long arms. Rare and beloved.
In this case all aspects of the horizontal rectangle are needed, but typically with longer stems due to the need to house the increased length of the arms. This type is a high custom candidate as bikes available with extra long top tubes are rare, much less one that would ride properly with a long stem.
Matching the right shapes between rider and bike based on flexibility and riding style is the first step in producing a perfect fit foundation to your perfect ride. Next month we will look at how geometry affects the personality of the bike and how identical geometries with different materials and construction methods can produce vastly different ride qualities and handling. Enjoy the ride.
Website: www.tadhughescustom.com
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