ropeadope

I just discovered a pitting spot on each cone of my front hub and I'm wondering how likely it is that the ball bearing(s) may be damaged as well. Are there ways to check for steel ball bearing damage? Maybe as simple as rolling them across a flat surface and listening?

wrk101

Why bother checking? I buy bags of 144 ball bearings for $3, thats 2 cents per bearing. It is not worth reusing loose ball bearings when new ones are so cheap. I get mine at Niagara Cycle Works.

gurry

Age of the bearings may be the best way to determine damage. When servicing hubs and such, it is advisable to install new bearings due to elongation of the old bearings. I do not know of a way to check for this.

neil0502

HillRider

Another urban legend. Ball bearings do not "elongate", "ovalize" or "get egg shaped" in service. This myth was perpetuated for years by the "Technical Expert" at Bicycling Magazine until an engineer form one of the big bearing makers (Timkin or SKF, I'm not sure which) finally wrote to say it was not true.

Replacing balls during an overhaul is cheap insurance against breakage but balls in good condition can be reused with no adjustment problems. If they aren't rusty, scored or chipped, they are fine. I know of one rider with nearly 100,000 miles on a Campy hub that still has the original balls. The hub has been cleaned and relubed numerous times and the balls are still completely round.

neil0502

It's all I can do to just let that one be....

HillRider

It's not unbelievable. I have over 50,000 miles on a 7700-series Dura Ace hub with the original cones and races still in it. I have changed the balls about every 6000 miles but that was a precaution. There were no problems with the ones I replaced.

The rider I referred to has thorough maintenance records so he didn't make this up.

neil0502

Oh, I absolutely believe you.

I was just being an elementary-school-level pervert

ropeadope

I see, I didn't know they were so cheap I've never bought them before. Thanks guys.

operator

yeah but to go from 6k miles to 100k miles for the same balls is quite a friggin leap.

bikemeister

Gosh, if only all bearings were like Campagnolo!!!!!

Panthers007

The key words to look for in ball-bearings is - Grade 25. This means they are top-flight bb's that are perfectly spherical down to 25/1,000,000th of an inch. Most bike outlets selling bb's will have this number prominently displayed in their description. Buy a bunch of all sizes - you will end up using them (or a friend will) and they don't "go bad."

Happy Trails!

sunburst

I bought them in volume in three sizes, based on recommendations here. It was great to reach into my spare parts box when I did a couple of bb and headset rebuilds recently, and have the correct sizes on hand.

Oh yeah, and to answer your question, a mechanic at my LBS said if they're shiny (after cleaning) they're still fine, if they're dull - replace them.

HillRider

Yeah, Campy bearing sets are supposedly superior quality and hand matched to exceed Grade 25 specs by quite a bit.

That said, you pay a super premium for the benefits. Campy's replacement bearing sets are vastly more expensive than regular Grade 25 balls so maybe that's why; 1)they last so long and 2) owners don't replace them.

sunburst

Someone gave me an old Italian bike (80's) that had been neglected, probably left out in the elements for years with lots of surface rust, frozen chain, etc. My local LBS mechanic said, if it were his, he would go through the headset, bb and hubs. When I inquired about price he said I should ride it until something breaks. Recently I discovered the front hub, which is campy, spins noticeably smoother and longer than any of my other bikes. Made me wonder why -- good bearings?

davidad

That's hype! Otherwise known as BS. Nobody is going to spend the money to match bearings.
Grade 25C balls are much better than needed in bike aplications.

DaveSSS 

While it's true that grade 25 is plenty good enough, Campy bearings are supposed to be grade 10.

https://americandad.biz/gradechart.htm

San Rensho 

The pitting problem was likely not caused by bearing failure. Pitting usually occurs when the bearing adjustment is too loose. In a properly adjusted bearing, there is no play, so all of the forces are distributed over all of the ball bearings. If the bearing adjustment is loose, then one or two balls tend to take all of the load, concentrating it on one area of the cup or cone, leading to pitting or a groove.