August 29, 2012

Chinese Carbon Bikes - Sizing

     After a couple of years of watching the Chinese Carbon and EBay Direct threads on the RoadBikeReview forums I have finally decided to try building up my own Chinese carbon bike.

     The most important thing when buying a new road bike is to know your frame size. There are many different ways to figure out what is right for you. There are some basic charts all over the Internet that give you a frame size based on your height or inseam. These charts are acceptable if you are perfectly proportioned and are buying a vintage frame which all had similar geometries. However, modern bikes come in all sorts of geometries and using a height based chart could result in a poor fitting bike which wastes both your time and money.

     There are a bunch of websites that have bike fitting calculators. These calculators work by collecting specific measurements from your body and using them to give you your ideal frame measurements. The main bike fitting calculators can be found on the Competitive Cyclist, Pedal Force, and Wrench Science websites. I personally like to use the one from Competitive Cyclist. I used it when ordering my BMC SLX01 from them and the results were great. I would not suggest measuring yourself as some of the numbers can be tricky to get solo. I first had my girlfriend help me but she was hopeless with the tape measure so I had a friend do it a second time.

     Once you have your results from a fitting calculator you can then begin shopping for a frame. Look for ones that you find visually appealing, that are within your budget, that have good reviews or are from reputable vendors... Once there are a few frames you have your eye on collect their geometry charts and compare them to your fitting results. If you have trouble finding the geometry for any given frame a quick email to the manufacturer will usually get you results within a day or two.

     Another way to fit a bike can be done by comparing a frame's stack and reach to your existing bike (if you already have a bike). Stack is an imaginary vertical line drawn from the centre of the crank axle straight up to the height of the top of the head tube. Reach is the horizontal line from the centre of the pedal axle to the centre of the head tube. In the geometry diagram above stack is labled as D and reach is labled as C. With these two measurements you can compare any frame to any other frame and get an idea of how it would fit on you. Many manufacturers currently include the stack and reach of a frame on their geometry charts to make sizing a bit easier.

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