You've seen the term "NOS bearings" in listings and wondered: what does new old stock mean, and why should I care? Here's the straight answer.
NOS meaning: new, just not new-made
NOS stands for New Old Stock. It means the part is brand new — never installed, never run — but it was manufactured years ago and sat in inventory. Think of it as a time capsule: a genuine SKF or Timken bearing, made to the original spec, in its original box, waiting on a shelf. Our SKF 6311 and SKF 6308-2Z listings are textbook examples.
Where do new old stock bearings come from?
- Distributor closeouts — a distributor drops a line and liquidates remaining stock.
- Plant shutdowns — factories close with spare-parts cribs full of unused bearings.
- Over-ordering — maintenance departments and OEMs routinely over-buy; the excess gets surplused.
- Packaging changes — a brand updates its box design and the old-box stock gets sold off, bearing unchanged.
Do bearings expire on the shelf?
Practically, no — if stored properly. Bearing steel doesn't degrade sitting still. What matters is storage: cool, dry, unopened packaging, no vibration. A 15-year-old NOS bearing stored correctly will outlast a 2-year-old used bearing every single time. The grease in sealed bearings (2RS, 2Z) has a long shelf life, and open bearings can be cleaned and re-lubed on installation.
How to verify genuine NOS
- Markings: genuine OEM etchings on the rings — crisp, precise, matching the brand's format.
- Packaging: original manufacturer box, tube, or wrap — not a blank plastic bag.
- Condition: no mounting marks on the bore, no discoloration, preservative oil intact.
- Seller reputation: buy from specialists who stake their name on authenticity, not random marketplace listings.
Why NOS beats both new-list and used
Current-production bearings at full list price are expensive. Used bearings are cheap but spent. NOS sits in the sweet spot: genuine, full-life bearings at surplus prices. For maintenance shops, rebuilders, and anyone keeping older equipment running, it's the smartest money in the bearing world.
Shop genuine NOS bearings
At RomTex Bearing & Supply, NOS is all we do — SKF 6311 C3, SKF 6305, SKF 6014-2RS, and dozens more — in stock in the USA and shipped with documentation. Browse the inventory and see what surplus pricing looks like on genuine stock.