When you’re buying an exercise bike, there are several features you may consider before your purchase. Resistance type, flywheel weight, and performance monitors might be among the first things to research. But what about that thing called “Q-factor?”

Q-factor is the horizontal distance between the inside points of the crank arms on your bike. The “Q” in Q-factor relates to the waddling gait and wide stance of ducks.

So why should we be concerned with the quack factor? Depending on your personal hip and leg anatomy, the right Q-factor measurement could reduce your riding efficiency and increase the potential for injury while riding.

Manufactures use a standard Q-factor measurement range of about 150mm for road bikes and 170 mm for mountain bikes. It isn’t uncommon to find Q-factor measures that fall in-between or outside this range. Many exercise bikes, road bikes, recumbent bikes, or mountain bikes may have a slightly different Q-factor that might affect how comfortable you feel on the bike, no matter what other features it may have.

While the we may be at the mercy of the engineering constraints of cycle bikes you can adjust the Q factor, even if the crank arms of your bike are set at a narrow Q factor. Bike fitting is a common practice that avid riders choose when they want ultimate comfort and riding efficiency while they ride.

Having a longer pedal spindle or sliding your cleats can easily add valuable millimeters to your riding stance. However, if the Q-factor is wide it will be difficult to make the adjustment lower. So, when in doubt, choose a bike that has a smaller Q-factor.

Unless you are riding multiple times per week for more than 30 minutes each ride, you might not notice the effects of having a Q-factor that does not fit you. If you are considering riding competitively or are trying to increase your performance during fitness classes, it may be a good idea to look at finding your ideal riding Q-factor. The best way to determine what Q-factor is right for you is to try different bikes and find the one that feels the most comfortable.

Once you find a bike that feels comfortable, measure the Q-factor and use that measurement as a guide for any bike you chose to ride. Riding in comfort will increase your desire to continue with your cycling program, leading to a more happy and consistent riding experience.

If you are curious on how bikes might differ in Q-factor, checkout these exercise bikes to see how different Q-factor might be when your looking to make your next purchase.