The short version
- New tapered bearings arrive with a preservative coating, not with grease. They must be packed.
- That coating looks oily enough to fool people, and it will not lubricate anything.
- New sealed hub units are the opposite. They are filled correctly and must not be opened.
- So the answer depends entirely on which of the two you are holding.
Open a box of new tapered wheel bearings and they look lubricated. There is a light film on every surface and it feels like oil.
Do new wheel bearings need grease? That film is not grease, and fitting them that way is one of the quieter ways to destroy a new part.
What that coating actually is
Bearings are protected during storage and shipping with a preservative that stops the ground surfaces corroding.
It is formulated to be compatible with most greases, so it does not need removing. It simply does not lubricate.
Tapered roller bearings are not lubricated in manufacturing. Packing them at installation is part of the design, not an optional extra.
Without grease behind the rollers there is nothing separating steel from steel under load.
Heat builds in minutes rather than miles, and the damage is done long before any noise reaches you.
How to pack new wheel bearings before fitting
Exactly the same method as an old one, with one difference. There is no old grease to remove first.
Work grease into the wide face until it appears at the narrow end all the way round. Rotate and repeat.
The full method is on the repacking guide, and whether a tool helps is on the packer page.
It is compatible with normal wheel bearing grease, and removing it leaves bare steel exposed while you work.
Cleaning is for used bearings, and that is on the cleaning page.
The sealed hub unit, which is the opposite
| What you have | Arrives with | What you do |
|---|---|---|
| Loose tapered bearing | Preservative coating only | Pack fully before fitting |
| Bolt on sealed hub unit | Correct grease, sealed in | Fit as it comes |
| Press in sealed cartridge | Correct grease, sealed in | Fit as it comes |
| Trailer bearing kit | Usually preservative only | Pack fully before fitting |
A sealed unit contains a measured quantity of a specified grease. Opening it to check or to add more makes it worse, which is on the sealed hub page.
What new wheel bearings need besides grease
New bearings arriving in a box invite a straight swap. Three things usually need attention too.
The races. New cones on old cups wear rapidly, because the old cup carries the wear pattern of the old cone.
The seal. Always new, every time the hub comes apart.
The hub cavity. Partly filled, separately from the bearings themselves, which is on the quantity page.
The first miles afterward
A newly packed bearing distributes its grease over the first stretch of driving.
Some settling noise and a slight temperature rise are normal. A hub that gets hot, or noise that grows rather than fades, is not.
What normal looks like is on the break in page.
Compare each hub against the one on the other side of the axle after twenty minutes.
A clear difference between sides is worth stopping for, and it is the cheapest check available on a fresh job.
Common questions
Do new wheel bearings need grease?
Loose tapered bearings do, always. They ship with a preservative coating that protects the steel but does not lubricate.
Do new wheel bearings need grease, or arrive greased?
Sealed hub units are, with a measured fill. Loose tapered bearings are not, despite looking oily in the box.
Do new wheel bearings need grease after washing the coating off?
No. It is compatible with normal wheel bearing grease, and removing it leaves bare steel exposed while you work.
What happens if I fit them without packing?
They overheat within minutes. There is nothing separating the rollers from the raceway under load.
Do I need to grease a new sealed hub assembly?
No, and you should not try. It contains a measured quantity of a specified grease and opening it makes things worse.
Do I need new races with new bearings?
Yes. The old cup carries the wear pattern of the old cone, and a new cone on it wears quickly.
Is some noise normal after fitting?
Slight settling noise that fades is normal. Noise that grows, or a hub hotter than its opposite number, is not.