Originally Posted by
fenny
I did some searching, and while I found a few threads about mismatched bearings, none really described what I'm looking at tonight.
My rear wheel is an A-Class ALX200. It's been spinning pretty rough for weeks, which surprised me because I've only had the bike for 6 months / 2000 miles. Tonight I pulled the bearings out, and on the drive side I found 9 shiny 1/4" ball bearings with clean cone and cup, as expected. On the left side I found 11 rough 3/16" ball bearings and a pitted cone.
I'm going to take the cone+axle+bearings to the LBS tomorrow for replacement, but has anyone else seen mismatched bearing sizes in a single hub before? How likely is it that it's supposed to be 1/4" bearings on both sides, and that this is the cause of the pitting? I've tried visually comparing the two cones, and they do look a little different, but it's hard to tell if it's just the pitting that's giving me that impression.
I had exactly the same situation on an A-Class rear wheel taken off a fairly new Felt road bike, wheel was making horrible grinding noises and on inspection water had penetrated the smaller left side bearings and they were covered in rust. Replaced them and fresh grease, problem solved, but it can't be a good design to be running such small bearings, especially if the sealing isn't adequate either, can it?