Panthers007

The problem with them is you didn't open them up and clean them and grease them. A pedal-overhaul is needed before you put most new pedals - especially with loose bearings - on the bike and use them.

I hear this complaint all the time regards MKS pedals. And it's NOT your fault. Overhauling pedals is a dying art. One I'm trying to resurrect. Here's what you do:

Working over a bowl, and the pedals removed from the bike, gently pry off the dustcaps at the end of the axles.

Now take a Y-Wrench socket-wrench and, while holding the flat where you screw it into the crank-arm with a box-wrench or pedal-wrench, remove the locknut under the dustcap. Then remove the cone under that. The bearings will pour out - into the bowl if you remembered.

Gather all the balls - 1/8th inch - and let them soak in a solvent such as charcoal-lighter fluid. Don't smoke - yet.

Now clean the insides of the pedal, the cone, the locknut, etc. with a rag soaked in the solvent. Allow to dry/evaporate completely.

Apply good-quality grease to the races where the balls ride. And begin the slow, tedious process of placing the balls back into the races - starting on the side closest to the crank-arm. Needle-Nose Pliers, or tweezers, work well. Then insert the axle to hold the bearings in place and repeat placing the balls on the other race - furthest from the cranks.

Screw the cone down slowly to hold the bearings in place. This will take several, or more, attempts your first time out. You want them to have no play back & forth - but you don't want them tight (like they are now before you began). Then replace the lockring and torque it down firmly. As I said - this will take a few tries to get it so there is no play, or tightness. It requires finesse. The second time you overhaul a pedal is much easier. It's an art.

Now you should understand the principal and the goal. Go for it! Congratulations! You will be a true artisan of a dying art!


<EDIT> I have many pairs of MKS pedals, and know many other folks who do also. Everyone experiences symptoms like you describe. Now our MKS pedals run almost as smooth as my old Campy Records from 1982.