sealed bearing questions.
I was going to repack the hubs in an old touring bike I bought but I as I was taking it apart I noticed the sealed bearings.
The sticker on the hub obviously didn't clue me in.
Anyway, how do you tell when a bearing is going bad?
How tight do you set the side pre-load?
These spin very smooth, but there is some lateral movement when the adjusting nuts are off the axle.
Snugging the adjusters up takes out all the movement but how tight should they be?
And lastly, how come some hubs that have the sealed bearing sticker have cones, bearings and a double lipped seal instead of a true sealed unit bearing??
There's a difference between sealed bearings (service-able bearings that are protected by some sort of seal) and cartridge bearings (not serviceable). Sealed bearings should be serviced, just like unsealed ones.
I adjust hub bearings so that they're a smidgen tighter than when you can feel some play with the rim when the quick releases (outer axle nuts if no QR) are tightened. YMMV
Only tests I know for hub bearings are
by feel -- does the axle turn smoothly by hand when cones have been properly lubricated and adjusted, and wheel is taken out of the fork or dropout -- and
by inspection -- visible pits/deformation on cones/races/balls with a magnifying glass.
Of course, if they're noticeably noisy while riding, then one of the other tests will probably show them to be worn out.
Originally Posted by Charles Wahl
I guess I should have clarified that I have cartridge bearings.
Do I snug up the adjusters on the cartridge type like you stated?
I can set up cones and bearings but the adjusting nuts on this axle seem redundant. Unless I am supposed to set the side to side preload with them.
Sorry, I know nada about cartridge bearings; have only one piece of equipment with them, that I've not yet installed. Time for someone else to jump in; or you could cruise on over to Sheldon Brown's bike tech treasure trove and read up about them.
Cartridge bearings (dual rubber seals,one on each side) like this one :
are easily serviceable, despite what everyone says.
Step 1: remove sealed cartridge bearing from hub or BB using the appropriate bearing removal tool
Step 2: take a scalpel or pin and carefully (without damaging the seal) lift up the seal. Remove both seals . Set seals aside
Step 3: immerse bearing into solvent (NOT Simple Green or Citrus- see footnote) and soak. scrub with toothbrush, spin the bearing and scrub again, until ALL traces of the old grease are removed.
Step 4: rinse bearing in clean solvent, spin the bearing a few times, rinse again.
Step 5: rinse the oily solvent residue from the bearing , using Acetone or 99% methyl hydrate. Spin the bearing by hand and blow dry with canned air. The reason we rinse the solvent is it leaves an oily residue that "cuts" or thins the fresh bearing grease, rendering it useless (does'nt adhere to the raceways or balls). So rinse the solvent form the bearing good...brake cleaner, acetone, methyl hydrate etc for the rinse liquid
Step 6: clean the seals, using a bit of methyl hydrate and a clean rag. Pop one seal back into the bearing.
Step 7: take a nickel sized dab of automobile wheel bearing grease, and work it into the bearing races and bearing balls. Pack the bearing about 60% full. Take the second seal and pop it back into the bearing. Wipe the bearing clean and re-install.
Footnote 1: the reason we dont use Citrus or Simple Green cleaners, is they contain ingredients that "wet out" the metal. These ingredients do not get removed, and prevent the fresh grease form adhering properly to the metal surface of the bearing raceways. Solvent rinses clean with methyle htdrate or acetone, and leaves no surfactants in the metal. There is a reason industrial users utilize solvent for cleaning metal parts exposed to movement.
Last edited by Bushman; 08-17-07 at 07:25 PM.
as for adjusting the pre-load on cartridge bearings, snug up the cone (different than a traditonal loose bearing/cone setup), finger tight, and butt up the locknut against it, fingertight. Take two cone wrenches and tighten both nuts against each other, but always turn the conenut next to the bearing TOWARDS the locknut, not the other way around. This will give you perfect sealed bearing adjustment, with about .001% freeplay.
I resurrected a Phil Wood BB first installed in 1974-5
and sitting up in the basement for 25yrs with Bushman's
method. Works well as long as you don't ****** up the
seal on R&R. Important that you don't overpack with
grease so that 60% is significant if you can figure out
how to measure it. Lubriplate will give a bit lower
rolling resistance, probably at the expense of lifespan.
+ 1 on Lubriplate!!! good stuff. You can also purchase extra rubber seals from a bearing supply house when you buy your bearings, that way you can just toss the old seals and use brand new ones every time you service the bearings.
Thanks for all the info.
I may leave the seals in place as these wheels roll so smoothly.
It will depend on how much work it is to drive them out of the hubs.