I just installed new Timken bearings and races in my two year old FW with 20,000+ miles. The new bearings and races are all stamped "Made in USA". I've never had a Timken bearing fail, so I elected to change them in lieu of continuing to run on a brand I'm not familiar with. FWIW, the bearings I took out were manufactured in China and did not show any sign of premature wear. If you're not putting lots of miles on your trailer, I would leave things the way they are. Just clean, examine, repack and install new grease seals as warranted.