The Fitting Room
All the great bikes in the world are worthless without a great fit. We sell a great fit, and then a bicycle, rather than trying to make you fit onto a frame we have in stock. We would love it if there were a simple formula for fitting oneself to a bicycle. The fact is that you need a set of measurements and the help of a well-trained bicycle-fitting expert.
We are great believers in the Fit Kit System. This system takes precise measurements of your body and then makes suggestions as to how to initially set up your bicycle. From there, it is essential that someone takes a look at you and examines your position on the bike. The Fit Kit only goes so far; a myriad of unanswered questions come into play which affect seat height, seat setback, and handlebar extension.
No formula or book is the final answer.
Ideal position on a bicycle involves being set up correctly initially, being viewed by a professional, making your own small adjustments, and then being viewed again by a professional. And finally, and most importantly, it is a matter of comfort. If, even after all the measurements and recommendations you are uncomfortable, we rework and adjust until you are-even if it's not what the numbers suggest.
Despite this, there are some general formulas which you can use to get a rough idea of what size frame you need, and at what height to set your saddle.
For road bikes, take your inseam in centimeters, and multiply it by .65. This will give you your frame size.
For cyclocross bikes, take your inseam in centimeters, and multiply it by .63. This will give you your cyclocross frame size.
For mountain bikes, take your inseam in inches, and multiply it by .60. This will give you your mountain bike frame size.
Another good formula for seat height for the road is to take your inseam in centimeters, and multiply it by .883. This will give you your saddle height from the center of the bottom bracket to the level part of the saddle. You should be careful with this height. This is considered the optimal height for a trained rider. Simply throwing your saddle to this height can cause some serious damage to your knees. Move there gradually and realize that every body is different. Just because we think this is the optimal height, does not mean that your body or your pedaling style is suited for it. Take your time, and have a trained fitting expert look at your riding position.
We like to have photos sent to us of the rider on their current bicycle in their usual riding position. That picture, along with a description of what they are looking for, goes a long way in helping us obtain the perfect fit.
You might have noticed that if you type in the formulas for your inseam, your road frame is bigger than your cross frame, which is bigger than your mountain frame. This is because in cross, you want a frame that is a little smaller than your road frame. You will never be in the extended road position for more than a couple of minutes and you want to be nimble on and off your bike, thus the smaller frame.
For cyclocross, generally go with a frame that is one to two centimeters smaller than your road frame. Your saddle height is generally one half to one centimeter shorter than your road position. Stay with the same size cranks, and stem, as the shorter frame will give you a more compacted top tub section. If you shorten your stem as well, you will more than likely get a good amount of back pain, and be unbalanced on your bike. Handlebars should stay the same width as on your road frame.
For mountain bikes, generally go with a frame that is small enough to accommodate your torso's length. It is easy with long seat posts to fit a small frame to a larger rider, but, in general, you want to avoid stems which are longer than 130mm, if you can. A long stem has the barn door effect on steering. It takes a larger move at the end of the bars to get the bike to turn. For cranks, stay with your current road size or go a little longer to get better leverage. Stems should put you in the same amount of extension as you have on your road bike. Handlebars should remain at the same width as on the road.
For time trial bikes, we recommend the general road formulas, again as a starting point. Another recommendation is to speak with John Cobb at Bicycle Sports in Shreveport, LA. He has a website, www.bicyclesports.com, which is an excellent source of information on positioning and equipment for time trialing.