Tuesday, March 19, 2013

Cross Check Sizing

When shopping for a new bike, the best way to determine fit is to consult your local bike shop and take some test rides. Unfortunately, this is not always possible. When I purchased my Cross Check back in 2007, Surly had less of a presence than it does now. That meant none of the shops in my area had any in stock, much less one in my size. So, I had to try and figure out which size would work best for me. Throughout this process, I learned a few things that are useful in choosing the correct Cross Check.

The first thing to know is how they determine their frame size. Like most companies, Surly goes by seat tube length, and they use a "center to top" measurement. Be aware, however, that there are variations of this measurement. To some companies, "center to top" means from the center of the bottom bracket to the top of the seat tube. In the case of Surly, the measurement is from the center of the bottom bracket to the top of the top tube. So, the measurement does not include the portion of the seat tube which extends above the top tube. This actually makes a lot of sense, because there are arbitrary differences in length on this part of the seat tube from bike to bike. At any rate, adjustable seat posts make this part of the frame easily customizable, so it's more important to consider top tube length and standover height in order to obtain a proper fit. Standover is pretty easy to determine. While wearing your typical biking shoes, measure your inseam from floor to crotch, then select a frame that will give you at least an inch of clearance when straddling the bike with your feet flat on the ground. That brings us to top tube measurement. The Cross Check has a longer top tube than most bikes with road geometry. Because of this, some riders end up selecting a frame one size smaller than they would normally use. Keep in mind that handlebar reach is adjustable by selecting stems of different lengths. If your reach feels too cramped or too stretched out, try a shorter or longer stem before concluding that you chose the wrong size frame. Another factor which may influence your choice is your intended use. People who ride true cyclocross or a lot of trails might appreciate the extra standover clearance of a smaller frame, while those who ride mainly on pavement might want go bigger for a more traditional road fit.

There are a couple of other resources out there that are worth checking out. You can consult this handy spreadsheet to see which sizes other Surly riders have chosen. While it primarily consists of data on Long Haul Truckers, there are some Cross Check entries as well. Additionally, you can check out this post on the Surly website. It's not Cross Check specific, but it is a good primer on sizing.

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