Things You'll Need:
- Ruler or book
- Pencil
- Tape measure
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Step 1
Stand barefoot with your back against a wall. Wear your cycling clothing when measuring, especially if your shorts have extra padding in the inseam. Place a ruler or book between your legs so that it is pulled all the way up to the inside of your shorts. Mark the wall on top of the ruler or book and step away. Measure the distance in centimeters from the mark to the floor. This is your inseam measurement.
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Step 2
Calculate your ideal road bike size by multiplying the inseam measurement by 0.65 for bike frames that are measured center-to-center. If the bike frame is measured center-to-top, multiply the inseam by 0.67.
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Step 3
Convert the road bike size to your ideal mountain bike size, if needed. Subtract 10 centimeters from the road bike size. Convert this measurement into inches and you will have your mountain bike frame size.






