Your Height? Your Bike Frame Size?

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    Jul 17, 2014 10:54 PM GMT
    For your height, what frame size do you find most comfortable?

    Have you found any difference in the sizes you need for a road bike versus a mountain bike or a hybrid?
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    Jul 17, 2014 11:18 PM GMT
    I only do road bikes. I am short (barely 5'8") and my legs are even shorter for my height, a finished dress inseam of about 28-3/4".

    I get the tallest frame I can, because it gives me more room (on a road bike) to stretch out to the handlebars (sometimes fitting a longer handlebar stem), being that my torso is disproportionately longer than my overall height suggests. A larger frame also give me a longer wheelbase, which I like for riding comfort & stability.

    My only mandatory criteria is that I have an adequate "standover" height. That's the height of the top tube from the ground, when you're standing on your feet, so it doesn't mash into your crotch.

    Better bikes will give you this standover height in their specs. If you know yours (with your riding shoes on) then this can help you choose the frame size.

    My frame is usually around 19"/48cm (taken from the seat tube length) with 28"/700mm tires. This sometimes varies if the top tube is angled. Again, the key dimension for me is standover height, whatever is the highest I can manage in a road bike frame, usually no more than 30". I've followed this formula for over 50 years.
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    Jul 18, 2014 3:56 AM GMT
    I'm not sure that you can use a universal number. For me, on a road bike, when the top tube is horizontal I need a 64 cm frame. I'm 6 foot 3 inches. But someone else may be the same height and have shorter legs than I do.

    Newer road bike frames have a slanted top tube and I think it's normal for them to have the seat raised a lot higher over the frame.

    frame_geometry.jpg
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    Jul 21, 2014 5:53 AM GMT
    I'm 6'2" and I've always ridden 58 cm bikes. I can ride a 60 cm, but I tend to sit fairly forward, so it's difficult to get my saddle to the right position with a longer reach.

    If you are comparing different models of bikes, take the time to look at the geometry charts and graphs. The most important factors are Stack and Reach. You can't go by seat tube, top tube, and head tube lengths alone to get the right fit because different angles of those tubes can still put you in the same relative position as a larger bike.

    Another suggestion would be to go to a shop that has a fit machine to get your ideal position dialed in and then match it as closely as you can to the bikes you are considering, with minor adjustments in the crank arms, seat height and stem length. You and I could be the same height but need many different adjustments based on leg and torso length which varies from person to person.
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    Jul 21, 2014 6:15 AM GMT
    erik911sd said
    Another suggestion would be to go to a shop that has a fit machine to get your ideal position dialed in and then match it as closely as you can to the bikes you are considering, with minor adjustments in the crank arms, seat height and stem length.

    Yes, a fitting rig is very good for a beginner, to establish his ideal bike dimensions. They didn't have those when I started in 1962, I just learned by trial & error. Now I know the sizing that works best for me by heart.

    But the OP should be prepared to pay a fitting fee for this service, which can be a bit pricey. Which may or may not be credited to his subsequent bike purchase from that shop. He needs to find that out. But having a professional fitting done can be a good idea.

    And you don't have to have a frame custom built to your dimensions, which is mega-expensive. As you say, swapping less expensive components like the handlebar stem and seat post can customize a bike's sizing very effectively. I often get a longer stem to give me more stretch-out room, on what is a relatively small, compact frame because of my short legs.
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    Jul 21, 2014 4:57 PM GMT
    Bike fit and frame size are dependent on the type of riding a person does.

    Road biking requires a different fit than commuting, which requires a different fit than beach cruising, which requires a different fit than off-road trail/mountain biking, which requires a different fit than downhill mountain biking, which requires a different fit than slopestyle riding, which requires a different fit than freeride mountain biking, which requires a different fit than BMX.

    To avoid confusion, the best thing a novice can do is just ride. As experience builds, any needed changes will become apparent, and can be addressed. Until then, just ride. icon_biggrin.gif