Determining Correct Frame Size
If you have a bike already, and you like that riding position and want to duplicate it, you can take certain dimensions from that bike to achieve the same fit. If you need help with sizing and fit, please contact us for assistance.
Duplicating an Existing Position
Follow these steps to duplicate position from another bike (see diagram below):
1. Measure from center of BB to top of seat surface along axis of the frame's seat tube.
2. Drop a plumb line from the tip of the saddle and measure distance horizontally from there to center of BB. (These dimensions position the seat in relation to the BB.)
3. Measure from tip of seat to center of handlebar, parallel to the floor. This positions the reach.
4. Measure from the top of the saddle directly above the seat post, to the floor. Make sure you measure perpendicularly to the floor.
5. Measure from the centerline of the handlebar to the floor. Make sure you measure perpendicularly to the floor.
These last two measurements allow the stem height to be positioned correctly in relation to the seat height.
Measure twice (at least)!
If possible, metric dimensions are preferred, as they are easier to work with. All you need to do is send or tell us the 5 measurements from the list above, and we can do the rest. Please also include your height and inseam measurement (crotch to floor, barefooted).
Sizing a New Frame
If you're starting from scratch, the chart below will get you in the ball park, assuming you are of fairly average proportions. These sizes are assuming an aggressive (but not racing) style of riding. Frame sizes (measured in cm, center to center) are listed across the top of the chart, rider height is in the left column, and suggested stem extensions are in the body of the chart. For example, for a 6'1" person with standard proportions buying a 55cm size, the recommended stem extension would be 120mm. With longer legs/shorter torso, you might want to go to the 58cm size, with a 100 or 110mm stem. Also, if you want a more upright position, the stem can be mounted higher on the steerer tube, and a shorter extension can be used.
Sizing information on various components
Sizing of most components is a personal choice, and the more riding you've done, the more you know about your riding style and what you need. What follows is a brief summary of information to think about when choosing the sizes of the various parts on your bike. The default sizes on the spec pages reflect the standard, average sizes for any particular size frame.
Handlebar width: Generally the width of the bar should allow your arms to be parallel when your hands are in the outermost position on the bar. Narrower bars allow more maneuverability in tight spaces, while wider bars allow the chest to open up more for better breathing.
Stem extension: Stem length impacts your riding position, efficiency, and comfort. If you are male and have generally average upper and lower body proportions for your height, the default size should be okay for you. Shorter lengths are for when the upper body is proportionally smaller than average. Most females fall into this category. Also, if you prefer a more upright or more laid out position, you can go smaller or larger respectively.
Crank arm length: The traditional length is 170mm and works well for most people. Generally, if you are taller with longer legs, you might want to use a longer crank, a 175mm size. However, for fixed there are two points to consider—cornering clearance is decreased with a longer crank, and for high RPM riding shorter cranks work better. If you are on the shorter side, a 165 may work better for you. The advantage is the higher leg speed possible with a shorter crank. The disadvantage is the loss of leverage for climbing. So, if you're in a hilly area, the 170 is usually the best compromise.
Chainring and rear cog tooth sizes: This is all about gear ratios (see charts below). As with all of these parts, the size of the sprockets is a personal choice. The default gearing provides a generally popular mid-range gear ratio, allowing a flat road speed of 18.5MPH at 90 RPM—small enough to climb all but the toughest hills, and not too small for the downhill ride, to keep RPMs from getting too high.
Gear chart for 700c wheels:
Gear chart for 650c wheels: