Does your Mountain Bike
Fit you Properly?


A proper mountain bike fit is important for many reasons. It affects your comfort while riding, the performance of your bike, and the safety of your ride.


Most bike stores do some type of mountain bike sizing when you are trying out or purchasing a bicycle. The quality of the fitting varies from store to store and also from salesperson to salesperson. Many bike shops also may have a more involved and detailed fitting that costs extra.





Regardless of what type of mountain bike fitting you get, it is important to know the following information for when you need to make adjustments or replace parts on your mountain bike in the future.


Getting your bike to fit you properly involves the following:

  1. Find the right frame size
  2. Adjust bicycle seat: Height, tilt, and fore/aft position
  3. Adjust handlebars
  4. Set shock preload based on your weight and riding style



1. Mountain Bike Frame Size

When determining mountain bike fit, the first thing to consider is the frame size. Although adjustments can be made with the handlebars, seat, and pedals, these adjustments are small and will not help if your frame size is too big or small. When looking at frame size, two important things to consider are standover height and the distance from the seat to the handlebars.


Standover height is the amount of space you have between the top tube and your crotch when you are standing over the bike right in front of the seat. Different types of mountain bikes require different amounts of standover height. For cross country bikes, 2-4 inches is often recommended; however, how much standover you choose is a matter of personal preference. I like to have at least a couple inches so it is easier to bail when necessary. Although some do not think standover height is important, I have demoed bikes that have little or no standover height and do not feel comfortable with it. I refuse to buy a mountain bike based on that reason alone even if I love everything else about the bike and it fits in other areas. But again, it is a preference and it also depends upon how aggressively you ride. Downhill and freeride mountain bikes often have more standover height, like 6-8 inches.


It is also important to consider the distance from the seat to the handlebars. This distance is determined by the length and angle of the top tube of the bicycle frame. While sitting on the bike, a good neutral place to start is at a distance where your back is at a 45 degree angle when arms are slightly bent. This distance should be varied depending on your comfort and the type of riding you will be doing. If you feel crowded, the frame is too small. If you are too stretched out, try a frame with a shorter top tube.

mountain-bike-frame-size-sm

For more detailed information on mountain bike frame fit including a diagram, please visit our page on frame sizing.



2. Mountain Bike Seat Position

Once you have a mountain bike frame size that fits you, you can make adjustments with the bicycle saddle and other components in order to provide a better mountain bike fit.


The mountain bike seat is attached to the bicycle with either a 1 or 2 bolt design. By loosening these bolts, you can adjust the height, tilt, and fore/aft position of your seat. To test your bicycle saddle position, sit on your mountain bike near a stable object that you can hold on to so that you are in an upright position. Wear the shoes you will be wearing for riding.


To determine mountain bike seat height, pedal backwards until one leg is in the down position. While in this position, your knee should be slightly bent at around 20-25 degrees.


The tilt of your bicycle seat determines how level it is from front to back. Most riders prefer to start in a neutral position so that the seat is level with the ground, then small adjustments are made based on comfort and riding preferences.


Fore/aft saddle position is how far forward or backward your mountain bike seat is. A good rule of thumb is to have the bone that sticks out from the bottom of your kneecap lined up with the center of the pedal axle when your pedal is in the 3 o'clock position.

bicycle-seat-height

For specific instructions on adjusting your mountain bike seat, including photos and diagrams, please visit our Mountain Bike Seat page.



3. Mountain Bike Handlebar Position

Another way to adjust mountain bike fit is to adjust your handlebars. Your handlebars should be 4-6 inches wider than your shoulders. Wider handlebars are better for downhill riding because you have more leverage. Narrower ones are better for quick turns and climbing.


The height of your handlebars should be based on your comfort and riding preferences. A good starting point is to have the seat level with the handlebars. Having the seat a little higher gives you more stability for downhill riding. A little lower gives you more climbing power.


On most newer mountain bikes, the height can be adjusted by adding or removing spacers that are located above or below the stem. If your mountain bike does not have spacers, it probably has a threaded headset, in which case you loosen the bolt at the top, move the handlebars to the position you want them, and then tighten the bolt.


In order to move your handlebars forward or backward you need to change your mountain bike stem; however, you can make adjustments in the position of your handlebars by rotating the handlebars in the stem. This simple adjustment can make a big difference in how comfortable your arms are when riding.

handlebar-spacers

For more detailed information on adjusting your handlebars, including photos, please visit our page on Mountain Bike Handlebars.



4. Adjust Shock Preload

Once you have your mountain bike fit set up, its a good idea to check the preload of your front and rear shocks. To check your preload, attach a zip tie to the bottom of one of the stanchion tubes on the shock fork. Sit on your mountain bike in your riding position and then check to see how far the zip tie has moved. For cross country mountain bikes, it should have moved around 25% of the shock's total travel. For downhill or freeride mountain bikes, around 40% is usually preferred.


Most cross country mountain bikes have air shocks. Most downhill and freeride mountain bikes have coil shocks. More preload means the shock needs more force to move. To increase preload, add air to air shocks. Coil shocks are adjusted by turning a screw knob or a spring collar.

mtb-shock-diagram

For more detailed information setting up your mountain bike shocks for optimal performance, please visit our page on Mountain Bike Shocks.



Ready for the Trail

Now that you have a proper mountain bike fit, you are ready to hit the trail. Once you get out there riding for a while, you will be able to see how your bike performs and how comfortable you are after riding for a couple hours.


You may want to make more adjustments after seeing how your bike feels and performs. It is important to make only one adjustment at a time because this way you can see how each adjustment affects the comfort of your ride and the performance of your mountain bike.

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