Dead_Ant

So I'm ordering some bulk bearing balls, and I always get mixed up on the sizes and count for the various ball bearings.

What are the typical (I know there are a few oddballs out there) sizes and quantities for bottom brackets, front hubs, rear hubs, and headsets?

I've used the search function and most people just say to take them to an LBS, which I have done in the past. This time, however, I'm ordering bulk online and can't for the life of me remember the sizes that I used in the past.

neil0502

Try here?

https://www.sheldonbrown.com/harris/bearings.html#balls

Dead_Ant

Thanks for the link.

I always check Sheldon before posting...I wonder why I couldn't find that!

lc911t

Note that your bike may use different sizes than Sheldon's table.

Best to disassemble your bike and use calipers to measure the bearings.

Buy grade 25-100 (the lower the number, the rounder the ball) in batches of 100.

Don't throw away the old bearings until you've installed, adjusted, and test ridden the new ones.

wrk101

1/4 inch rear wheel (9 per side), 1/4 inch bb bracket (11 per side as I recall) and 3/16 inch front wheel (10 per side).

Buy a micrometer. I got a digital one at Harbor Freight for around $10, one of my best tool investments.

DMF 

Not good advice. What do you suggest he does with them, put them back in?

NEVER mix batches. Even more than nominal size - and even sphericity - bearings in a race must be uniform. Batches can vary considerably from batch to batch, and a single BB that is .0001 larger than its neighbors can destroy a bearing very quickly.

Take them out and throw them away.

bubbagrannygear

funny - I was thinking that saving the old bearings until the new ones are proven is great advice. If the new bearings are the wrong size, you will have the ability to remeasure the originals, or take them to a shop so they can match, or if you don't have fast access to more bearings reinstall them until you get replacements. Not everyone has the tools to measure accurately and a 7/32" bearing looks very similar to 1/4".

operator

Really? Then you have no business, overhauling hubs.

HillRider

Park makes a ruler that has graduated holes that are very convenient for sizing bearings.

And, unless you see them side by side, a 7/32" and a 1/4" are hard to tell apart at a glance.

bubbagrannygear

perhaps, but readers of Bike Forum are of varied competancy and resources, so any advice given should take this into account - "saving the old bearings until the new are proven" can save someone less equipped some trouble.

dedhed

a single BB that is .00001 larger than its neighbors can destroy a bearing very quickly.


Seriously, it's a bike, not a F1 car. A bike might see 200 RPM.

Panthers007

+2 Many companies make these rulers - for measuring spoke-lengths - with the holes for measuring ball-bearings. Park is probably the most common one in the USA. It's a must-have device for beginning mechanics and shops. Hunt one up. They're cheap.

neil0502

Wunna' these'll work, too. Cheap at the hardware store:

DMF 

If you can't tell the difference when you see them side-by-side

....


you probably can't reed this so never mind.

DMF 

So if bike bearings aren't under some considerable stress, why do they ever fail?

Just like an F1 car bikes are designed to be lightweight. That means that the heavy parts - solid steel bearings, for instance - are made to be as small as will do the job (though unlike F1 within cost parameters). The loads on bike bearings may well be *higher* than applications with which you're familiar.

IOW, your analogy is pretty bogus.

HillRider

Did you reed what I rote? I said; "Unless you see them side by side....".

joejack951

Contaminated/lack of grease, cheaply manufactured races/cones, improper preload, abuse. Need more reasons?

dedhed

The point was a bearing 10 thousandths out from the other at the speeds and loads typically found on a bike isn't going to destroy anything very rapidly. The F1 was just an example of a mechanism that really does need good bearings in most applications due to high speeds and stresses. I probably should have said your local dirt track beater.

I've seen plenty of old bikes that didn't even have all the balls, in gritty old grease, much less within hundreths of each other, that were still functioning in normal use. Were they smooth and efficient? Certainly not, but still being ridden daily. I can't picture me saying to anyone I buy bearings from "please make sure they are all from the same "batch""

operator

Rofl, subtle insult in posts ftw!

I applaud you, hillrider.

operator

Lol.

This is the most incorrect post of the day. Congratulations.

nitropowered

you really only need 3/16 and 1/4s

DMF 

Subtle? How 'bout for subtle that the misspelling was purposeful. Hm?


Fwiw, my post wasn't replying to yours, HillRider, except insofar as that when changing bearings, the mechanic *will* see them side by side (or rather should).

Panthers007

With the proper tools and a clear work area, I can't figure how anyone could manage not to check the size (unless they are an old hand) and use the correct bb's to re-pack the whatever. But I guess it happens. I always replace the bb's with new ones - from the same batch. The old one's are examined. The cups & cones are cleaned and inspected for any pitting/damage. Never had a problem.

And you shouldn't either. Take your time. Speed comes with practice.

lc911t

Not at all. Throw away old bearings by all means; just don't throw them away until you've installed and verified that the new bearings work. You never know when you have to go back and check size and count on the old bearings.

exRunner

Right advice, but I think you have a couple more 0's in there than you need. Dropping a bearing on the floor can move it more than one-one hundredthousands of an inch.

We are a big presision manufacturing company and we can't go that low with our laser, not that we ever need to.