<p>There comes a point in time when you need to change your mountain bike pedals—maybe you got a new pair, maybe you’re switching from flats to <a href="https://www.thoughtco.com/install-clipless-pedals-365426" data-component="link" data-source="inlineLink" data-type="internalLink" data-ordinal="1">clipless</a>, or maybe you’re letting your friend borrow your bike. Whatever the reason, learning how to change your own bike pedals is a good skill to know…if only so you don’t have to pay a shop to do an easy, five-minute job. Aside from your spare set of pedals, you’ll need a pedal wrench or <a href="https://www.thoughtco.com/how-to-change-a-bicycle-pedal-2403521" data-component="link" data-source="inlineLink" data-type="internalLink" data-ordinal="2">hex wrench</a> (if there are no pedal wrench flats) and grease to get the job done right.</p>Lean your bike up against a wall or secure it in a bike stand so it stays in one spot for the duration of the task. It’s a good idea to shift your chainring into your big ring before you go about loosening (or tightening) your pedals. This way, if your hand slips when you’re applying pressure to the wrench, you won’t find yourself with a gash from sharp chainring teeth. Simultaneously, shift and “pedal” your crank arm until you are in the appropriate ring. If your bike is leaning against a wall, shift, then “pedal” your crank arm while lifting your saddle so your rear wheel is off the ground.To loosen pedals that are already on your bike, fit the appropriate size pedal wrench over the wrench flats between the pedal and the crank arm. Apply as much pressure as needed to loosen the pedal. Note that the left pedal is reverse threaded. This means the old standby, “righty tighty, lefty loosy” does NOT work on this pedal. You’ll need to rotate the wrench toward the back of the bike (as if you were tightening it) to loosen.Keep in mind some pedals don’t have wrench flats. If yours doesn’t, you’ll need a hex wrench to get the job done. You’ll notice a spot for this type of wrench on the back side of the crank arm at the end of the pedal axle. Choose the correct size wrench and rotate in the appropriate direction to loosen the pedal. Remember, left pedals are reverse threaded. Pretend you’re tightening it if you want to remove it.Before installing pedals on your mountain bike, make sure the threads of the pedal are clean. Cleaning the threads of the crank arm won&#39;t hurt, either. Next, apply a layer of grease to the threads so they don’t end up seizing to the crank arms down the road.Look for a designation on your pedals to distinguish between the left and the right. You can typically find an “R” or “L” mark on the pedal axel spindle. Use your fingers to hand tighten the pedals. Make sure the pedal goes on without resistance—you don’t want to strip the threads on the crank arm. Once pedals are threaded on, tighten securely with a pedal or hex wrench.