Seat Height Fore Aft Position

This is first of a series on comfort and fit to engage riders in a new way of seeing themselves and their bicycle together. The thing that is most important in this relationship is rider comfort. How do you know what’s comfortable? Some experts will tell you that if it doesn’t hurt  a little then you are doing something wrong. Huh? Let’s get something straight. Would you buy a shoe that is a size too small? So listen to yourself, only you will know what is comfortable. How you get there often takes trial and error. Remember, trial and error. Don’t settle for less. I want to give you three areas to become familiar with so that you can prepare your bike fit. Do this mentally first and then get your wrenches. Having a rider friendly helper makes all of this easier so don’t be afraid to enlist a hand to help steady you and your bike. When the time comes to fine tune adjustments a seasoned rider is indispensable.

There are three points of “contact” your body has on a bike that relate to fit. Those three contact points are handlebars, seat and pedals. Contact points all work with respect to your body size type. Body size in basic terms is broken down into 3 types. Long limbs and short torso. Long torso and short limbs. Torso and limbs are average or about same scale.

Here is what you want to accomplish with seat height. While seated on the bike with your feet on the peddles rotate to the bottom position on the downstroke. There should be a slight bend at the knee for proper fit. If you are used to a seat position with your feet touching the ground while seated then possibly is going to feel awkward at first. Don’t sweat it.

The seat also has a second function that integrates your body type, (have you determined your type?) bicycle geometry and handlebar components. This maybe  is the least understood adjustment. So here it is. The fore and aft seating position of a rider controls the handlebar contact point and pedal contact point.

This is where trial and error on your part comes in. The idea is to get familiar with your seat. All seats are built with rails that attach to the seat post. Look under the seat and you’ll see the rails. Those rails give approximately 3-4 inches of travel fore or aft. Here is basically how you get started. Loosen the nut that secures the rails to the seat post. Don’t take the seat off the post. Watch carefully how the seat will tip up and down and fore and aft as you loosen the nut. Now you are ready to “field” test your seat adjustment. Secure the seat nut so the rails are either all the way foreward or pushed all the way aft. Make sure the seat is level before you tighten the adjustment. Have a rider friend lend a hand. They can straddle the front wheel and hold onto the handlebars every time you make the fore aft adjustment. It’s as simple as  a ride around the block to get this right.

Here is what you are trying to accomplish. First the hard stuff that I have outlined. Know your body size type. Take into account the geometry of your bike frame. See how handlebars, stems, crank arm length and pedals relate to your fore and aft position. The outcome is not that complicated when you realize fore and aft position is really no more than half the distance from the center of the seat rail and that is about 2 inches to play with. Come on now and see for yourself how a little adjustment can make the difference with comfort and fit.

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3 Comments

Filed under bike advocacy

3 responses to “Seat Height Fore Aft Position

    • this was quick post before I added Rider Reach = Bike Fit page. As If! I get that some of my explanation was not clear and just edited in copy on body type. Maybe that makes better sense. I appreciate your feedback about comfort and performance issues you might have with the types of handlebars you ride in urban situations. What can you add?

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