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Choosing the Right Size Bike

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    Measure from the ground to your crotch with your legs spread. Stand barefooted (or just wearing socks) on the ground with your legs spread apart. Move your feet apart so they’re separated by about 6–8 inches (15–20 cm) of space. Use your tape measure to find the distance from the ground to your crotch in centimeters. Make sure you’re measuring to your actual crotch and not just the crotch of your pants.
    • If you find that it’s awkward to measure this distance on your body without falling over, ask a close friend or partner if they’d be willing to help.
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    Multiply your inseam length by 0.7 if you’re buying a road bike. If you bought a bike whose seat tube was the exact same length as your inseam, you’d have a very hard time pedaling the bike! So, multiply by 0.7 to shorten the inseam measurement if you’re planning to ride a road bike. Road bikes are a great option if you plan to do most of your cycling on paved paths.
    • Say that you measure the length of your inseam at 65 centimeters. Multiply this by 0.7 and you’ll come up with 45.5. Rounding up, you’ll have an answer of 46.
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    Multiply your inseam by 0.66 if you’d like a mountain bike. Mountain bikes have thicker, bulkier tires than sleeker, more streamlined road bikes do, which means that you’ll be elevated a little higher off the ground. To compensate for this, multiply your inseam by a slightly smaller number to calculate your correct bike size. If you don’t like doing math in your head, find a handy calculator or use the one in your cell phone.
    • Mountain bikes are your best bet if you’ll be doing the majority of your cycling off-road or over rocky terrain.
    • For example, say that your inseam measured 76 centimeters. Multiply this by 0.66 and you’ll get roughly 50.
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    Purchase a bike with a frame size that matches the number you calculated. The number that you got as the result of the equation you just solved corresponds to the size of bike that will fit your body. It’s smart to try out a bike before you buy, though, to make sure it feels comfortable. Ride the bike around a parking lot and adjust the seat until each leg is bent at a very slight angle when they’re fully extended pushing down on the pedal.
    • If the bike doesn’t feel right or if you struggle to reach the pedals, try a different size until you find a bike that suits you.
    • If you purchase a used bike that doesn’t happen to display its size, you can pull out your tape measure and measure the seat tube to find the size.

     

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     Size Chart

    Road Bike Sizing:
    Rider Height Inseam Frame Size Frame Size (Inches)
    4’10” – 5’1″ 25.5” – 27” 46 – 48 cm 18-19
    5’0″ – 5’3″ 26.5″ – 28″ 48 – 50 cm 19-19.5
    5’2″ – 5’5″ 27.5″ – 29″ 50 – 52 cm 19-20.5
    5’4″ – 5’7″ 28.5″ – 30″ 52 – 54 cm 19.5-21
    5’6″ – 5’9″ 29.5″ – 31″ 54 – 56 cm 21.5-22
    5’8″ – 5’11” 30.5″ – 32″ 56 – 58 cm 22.5-23
    5’10” – 6’1″ 31.5″ – 33″ 58 – 60 cm 23.5-24
    6’0″ – 6’3″ 32.5″ – 34″ 60 – 62 cm 24.5-25
    6’2″ – 6’5″ 34.5″ – 36″ 62 – 64 cm 24.5-25
    Mountain Bike Sizing:
    Rider Height Inseam Frame Size Centimeters
    4’11” – 5’3″ 25” – 27” 13 – 15 inches 33-38
    5’7″ – 5’11” 29″ – 31″ 17 to 19 inches 43-48
    5’11” – 6’2″ 31″ – 33″ 19 to 21 inches 48-53
    6’2″ – 6’4″ 33″ – 35″ 21 to 23 inches 53-58
    6’4″ and up 35″ and up 23 inches+ 58-64
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