Stainless vs. chromed bearing balls
 

Sorry if this is an old topic, but the search function at BF is broken, apparently, for several days now.

I've never bought bearing balls before, and needing some, I would appreciate C&V opinion about whether to use stainless or chromed balls. Stainless are slightly more expensive than chromed in the Grade 25 variety, but I know that chrome is harder than stainless, too. So, what say ye?

Thanks,

If I take the time to repack the bearings, the pennies extra for the premium bearings is worth it, even on a Schwinn flipper. The major cost is labor, not materials, so why not use the best materials.

I liken it to putting a roof on your house; do you want the 15 year shingles of the 40 year? The forty year aren't THAT much more money.

Discloser: I will use cheaper grease on the Schwinn than on the De Rosa, I am a cheap buzzard, after all!

Sorry if my question wasn't clear: I wasn't asking whether to use Grade 25 or Grade 200 bearings; I'd like to know whether people think stainless or chromed are the material to buy -- both are Grade 25. Stainless might be more expensive than chromed, but chromed might be better for bike applications because surface is harder. Then again, if you'd prefer bearing balls to wear out rather than races or cones, the stainless might be better, though you have to replace them more often.

Good question. I am interested in this answer too. jim

I did not know they were available in S/S ...but many years ago I put some normal bike shop chromed bottom bracket bearings in my speedsix and within forty miles they were shot!
The bearings broke up!
Ever since then I have gone for "aircraft quality" bearings and had no trouble.....Unless they are horrendously expensive then I would always go for quality....just keep some spare cups on standby!

Just to clarify my post....Stainless although available in varying grades, is probably the safest bet.
Chromed bearings can break up and damage the cups which may be difficult items to replace?

Also there is a tendancy for chromed bearings to be of a mixed quality from various sources thrown in a plastic bag?

The "roundness" of the bearings is also to be considered?

just a few thoughts...

I use grade 25 chromium, no issues on any of my bikes. My understanding is that they are chromium steel, not chrome plated. I've never tried the 440-C stainless bearings.

I'm no expert, but it's my understanding that stainless balls are softer than chromium balls and are only advantageous in a wet environment like submerged pumps.

+ 1: the Grade 25 chromium steel balls are the hardest (Rockwell scale) and "roundest" (that's why they are grade 25) but they will rust if you get them wet and keep them wet. I would only go with SS balls if I expected to encounter a lot of saltwater and had doubts about my well-packed grease staying in place. SS balls may be available as Grade 25, but they will surely be softer (lower Rockwell) than chromium steel. Most folks only choose the softer balls when their cones/races are compromised.

As I understand it, the "Grade" number corresponds to roundness (technically, "sphericity") -- although it also corresponds to variation in diameter allowed within a lot. Here's a useful chart:
Bearing Ball Grade Chart

You're absolutely right about that; it's chrome alloy steel, not chrome plated steel -- I did a bit more research on that:
Chrome Steel Balls

Finally, here is a page from Park Tool that discusses Rockwell hardness (of chrome steel vs. ceramic balls, and races) and smoothness:
Ceramic Bearings

BTW, if you "need" balls that are Grade 10 rather than 25 (most bike experts would say you don't), those are available from Boca Bearings (www.bocabearings.com) for about double the cost of Grade 25 balls. I've seen several bike-related pages that claim Grade 25 to be "Campagnolo-quality."