One of the constants of the modern bicycle era is pedal thread. Except for one-piece cranks (as found on children’s, BMX, cruiser and older adult American bicycles like the Schwinn Varsity), an obsolete French standard and the Shimano Dyna Drive system of the early 1980s, whose oversize threads allowed the cantilevered pedal’s bearings to be located inside the crank arm, every crank arm today sports the same 9/16-inch pedal threads.
Moreover, virtually every pedal on the right side of the bicycle has a right-hand thread, while virtually every pedal on the left-hand side has a left-hand thread. (MKS offers an exception to that rule, the quick-release EZY and EZY Superior line. The pedals don’t have threads, though the couplers that attach them to the crank do.)
Note: When you’re talking directions on a bicycle, right and left are defined by the rider’s right and left hands as normally positioned when the rider is propelling the machine.
The right pedal spindle is tightened just like any garden-variety hardware store nut: in the clockwise direction (as you sight down the pedal toward the crank arm). The left pedal is the reverse. To tighten it, you turn the pedal wrench counter-clockwise.
One way to remember which way to loosen the pedals is to ignore “right-tighty lefty-loosey” in favor of “wrench rear.” It doesn’t matter whether you’re on the right or left of the bicycle, if you pull a pedal wrench extending vertically above the pedal toward the rear hub, you’ll loosen the pedal. Likewise, if you push the wrench toward the front of the bike, you’ll tighten the pedal.
Which is fine if the pedals are still attached to the crank. But if the pedals are sitting on your work bench, you need to know the right from the left to match them to the right and left crank arms.One method is to hold the pedal vertically with the threaded section up. If the thread slopes up from left to right, you have a right-handed pedal; if it slopes up from right to left, you have a left-handed pedal.
However, most people simply look for the letter stamps R (right) and L (left). Campagnolo pedals used to be stamped D (destro or right) and S (sinistra or left). Maybe they still are; it’s been a long time since I couldn’t live without Campy parts on my bike.
All of which brings us to the MKS FD-6 folding pedal. When new, the pedals have small sticky labels to indicate whether a pedal is left or right. But once you take the labels off, whether by hand or foot, you no longer have a letter to refer to.
If you don’t want to analyze the thread direction, the rule to remember with these pedals is “line left.” Hold the pedal vertically with the threaded section up and look at the shoulders of each pedal just below the threaded section. The left pedal has an engraved line that goes all the way around the spindle. The right pedal has no such line.
Throw a little grease on the threads and torque those babies on. (By the way, there aren’t any wrench flats for a regular pedal wrench; the FD-6 pedal is tightened using an allen wrench inserted into the end of the pedal spindle.) You’re ready to ride.