thriftyswift3

Hi!

I have been trying to find out a good source for loose ball bearings. I bought some at Ace Hardware yesterday, but was concerned they were named "Chrome Ball Bearings" or maybe they were "Chrome Steel Ball Bearings."

Does this mean they are chrome plated, and if so, wouldn't that be an unwise choice for a bearing? Seems to me the chrome plating could come off over time.

Or, is it normal for ball bearings suitable for use on bikes to have the word "chrome" in their title?

Thanks.

Iride01 

If you are going to put them in things that spin 10,000 or more rpm or have unusually high loading, then you might need to consult an engineer. For your bicycle, just make sure they are the correct size.

Chromed is fine, IMO grade of bearing with respect to tolerances is more important than materials.

FBOATSB

"Chromium steel" ball bearings are an alloy. They are hard but they will still rust. I've never heard of "chrome plated" ball bearings.

ThermionicScott 

Why not go to a bike shop for them?

WizardOfBoz

Pure iron (Ferrite) is soft and mostly commercially useless.
Add 4% or so carbon and you have cast iron. Can be moderately hard or soft but not accurately hardenable to allow use in modern commercial bearings.
Reduce the carbon to 0.2 to ~1.5% and you have steel. High carbon steel (1.2% or higher) can be very hard indeed, but is brittle. Holds and edge, so you can make a straight razor out of this.
If you formulate a steel with about 1% carbon, 1.5% chromium, and small amounts of manganese, phosphorus, nickel, copper, and molybdenum, you end up with chromium bearing steel. This type of steel is strong, hard, wears well and has a good compromise of other properties.

Chrome plating on steel usually involves plating with copper and nickel first, and the plating is brittle so a chrome plated bearing race would have the plating crack off very quickly. Too, the plating process does not leave a surface as precise as the grinding and polishing processes used for bearings. If you have bearings with the word "chrome" in them, then this is a chrome steel alloy, not plating.

As stated above, bicycle bearings are pretty low-duty low-precision compared to automobile and locomotive engines and wheels, and industrial electrical motors and machine tools.

If you got a chromium steel bearing that's the right size, you're probably ok. Unless the bearing was made in a fly-by-night Chinese factor that included rice hulls as part of the alloying content.

AnkleWork

Just WOW! You left out spheroidal graphite iron.

WizardOfBoz

Also missed wrought iron. I'm surprised no one has posted a question "Can I make a bike from wrought iron in my forge?"

mercator

Search amazon for Wheels Manufacturing bearing balls - I've been able to buy them at a very low price as an add-on item.
Or you can order them directly.

Iride01 

I think my response to the OP was a little more snippy than informative. So I'm not proud to have written that.
What I was attempting to get at wasn't even a factor of what the OP was asking.

davidad

shimano used a grade 100 in some of their hubs and grade 25C and stainless in in their top-of-the-line hubs.

thriftyswift3

I've had too many experiences where a bike shop seems only really interested in selling new bikes I can't afford and working on those new or other newer bikes. I wouldn't expect to be able to go to a LBS and buy a few ball bearings. I hope I'm wrong.

Also, I'd think they'd be marked up too much in price.

FBOATSB

Small quantities anywhere are going to be more. I get 500 assorted bearings for $7.45. https://www.amazon.com/Piece-Assorte...2145030&sr=8-5

ThermionicScott 

Last time I bought bearing balls, it was only a few bucks, and a bottle of 100 goes a long way. If they try to sell you a new bike with them, just say "no."

dedhed

I've found 100 doesn't go so far when you're doing headsets.

sharktrack

How big a difference does the grade of the bearing make? Say a 100 vs a 25, is that going to be noticeable in the long run (wear out faster, spin less smooth, ...)?

dedhed

For most of us, none, but 25's are readily available and cost difference negligible.

ThermionicScott 

Well okay, I was at work and not near my bike stuff. I guess my bottle of 150 5/32" bearings was $10, so my point stands that they're not going to put you into the poorhouse, even from the LBS.

Our OP can cross the bridge of needing them in larger numbers when he needs to.

thriftyswift3

Ha! Thanks. Not so much trying to sell me a bike as turning up their noses and/or telling me they can't help me.

But thanks!

thriftyswift3

Well, thank you all for your help! I really appreciate the responses!

Looks like the "Chrome" whatever bearings I picked up at Ace Hardware should do okay for me. I'm sure most of you here in the "mechanics" section are already privy to this info., but I was thrilled to find the following info.: https://bike.bikegremlin.com/2255/st...ng-ball-sizes/ It talks about deviation tolerances (No better than G 25 said to be needed for bicycles), and hardness (between 55 and 65 HRC). Sounds believable enough to me.

I've popped them in – 10 loose ones in place of the 7-in-a-cage. FYI, this is on my Sears (Murray) cruiser referenced in my thread entitled something like "Sears Bike From Probably the 50s."

sharktrack

This might be trending slightly away from the main theme but is there any benefit in replacing standard steel balls with ceramic? They're definitely more expensive but supposedly rounder and harder and may not need grease?

AnkleWork

A few answers here:
https://www.google.com/search?&q=sit...eramic+bearing

AnkleWork

I'm surprised you haven't disserted all about it without the question.

WizardOfBoz

There's a guy who calls himself Hambini. He's an engineer in the UK. He has a reputation as being a bit autocratic and controversial, but I think his analysis here is reasonably good. His tests seem to indicate that ceramics are nearly as good (for for friction) but not quite equal to the best steel ball bearings.
As an engineer myself, I have to say that for our bikes we don't need bearings designed for super duty. It's a bike. With a guy or gal on it. Not a 200kw electric motor driving a two-mile long coal conveyer belt. I use steel bearings in my bikes, FWIW.

https://www.hambini.com/ceramic-bear...ring-analysis/

Keep in mind that this topic generates feelings of almost religious certainty on both sides. Don't matter. Folks been riding bikes with steel balls (and even bushings) for over a century. Steel works fine.

sharktrack

Thanks for the link - looks like an interesting read!

davidad

Cost is not a factor and there is no real advantage to the better grade for our use. I believe that a bike wheel traveling at 30mph is only spinning at about 360rpm.