Ronsonic 

If I were pulling them and refreshing the grease as often as I suspect you are, then there wouldn't be a reason to replace them each time.

Being me, they often go for a few years between service so I need to be more thorough.

Gresp15C

I find that inspection is an important part of maintenance for me, because I'm not running a pro shop, and only get a few chances to improve my skills. Looking for wear is a way to see if I'm treating the bike right. By the time the parts are clean enough to inspect, most of the time is spent, and so I wouldn't really save time by disposing of the balls. And we're talking a couple minutes anyway.

andrewclaus

No. I volunteer in one co-op and two other non-profit shops. In all three shops, we re-use bearings, even have volunteers sorting and restocking. We aim to reduce waste, keep costs down, and have something for work-for-bike folks to do. (We also patch used tubes, salvage spokes, fix BSOs many would throw away just so some kid gets a free bike, etc.)

ThermionicScott 

I don't use solvent or rags to clean and inspect bearing balls. I just put them on a small piece of paper towel, fold part of it over the balls and roll them around with my fingers to wipe off the grease. That's quick and good enough to see if they are dull or pitted.

Reynolds 

+1 to above.
I don't usually replace them if they are OK, but when I do I always use loose balls not caged.

GromitDog

Depends, if its high end XT etc and its in good condition ie preventative maintenance then i usually clean and keep, but they must be shiny and not dull. Any damage to any part and its replacment time.

ign1te

If it is a hub that is regularly maintainenced, I inspect the balls. If I open the hub up and it looks like junk, most likely all of the balls are toast and I dont bother inspecting. In the cases i do inspect, I use a magnifying glass and a strong light to inspect each ball. If I can visually detect any flaw, I replace that particular ball. With regular maitainence on a rear hub, typically 3 or so balls need replacing.

Ronsonic 

Balls are graded according to how well they match the rest of their batch moreso than how closely they match the specified size. True, modern manufacturing brings them very tightly to spec, but still, I think you're into a false economy here.

High quality, grade 25 balls don't cost much in some quantity over 100, it makes sense to just replace them all at once and be good for a long time rather than going a few at a time and using your time to inspect them that closely.

Ronsonic 

If the OEM used anything better than standard grade 25s they would tell you very loudly in the marketing hype. Lower priced stuff is grade 100 or worse.

Campagnolo uses grade 5 in some stuff. Otherwise you can easily match or exceed the original quality.

AnkleWork

It would require some exceptional measurements of ball bearings in new bikes to know what grade OEMs use.

Bike Gremlin

Plus elastic deformation of cup and cone material is far greater than deviations that exist with balls with a grade of 25 and lower - so going for grade 5 balls, even with Campagnolo "stuff", makes no gains, not even in theory I think.

Koyote

Grade 25 (i.e., the best) ball bearings are cheap, and it is easier to replace them than to clean and inspect them. And my labor time for a hub overhaul is the most costly part of the job, so the bearings are a cheap add-on.

mixteup

Not to start a war, but I think THIS is a mistake, regardless of how you feel about routine bearing replacement.

If You find ANY ball in a race to be bad, I think you should replace ALL of them.
The reasoning being, that all the balls will in a batch will be similar spec, and if you swap in a single new one, you risk having that ball being a slightly different size, even minutely -
This would lead to uneven loading of the race.

Then again, maybe I'm being overly anal about this, but I worked as a mechanic in various capacities for many years, and it's just the way I think - YMMV

Bike Gremlin

You worked as a mechanic and had problems using balls from "a different batch"?
Tollerances are tollerances - grade 25 is grade 25, no matter which batch it comes from. Elastic deformation of bearing races far exceeds the differences in ball diameters. And they are pretty matched withg grade 100, even more with 25. No matter "which batch" you choose.

I had heard batch and even "wear in" stories from several experienced mechanics. Never had problems if using good quality grade 25 (or better) bearing balls. No measurable difference.

mixteup

I never had a problem, because I always followed that routine.
Whether I WOULD have had one, I don't honestly know - But I never took the chance.
If the balls all look good, you're probably fine in just cleaning and re-packing, but if ONE is bad, I'd replace them all.
Like I said, it's just me, and the way I approach mechanical issues.

rydabent

My two cents says----------------------if the balls are totally shiny without pits do not replace them. The reason is they are completely seated in to the races and have full contact. OTOH new balls may NOT totally seat, and would have to wear in. Wear is what you do not want.

cbrstar

As I collect vintage BMX's I have seen some of the worst wear possible. For me the struggle isn't replacing bearings but cones. Personally though I might be weird but I do use the original bearings and cones if possible, but then again you don't ride a BMX for 1000's of KM's.

cbrstar

I'm not sure with BMX's I have found where for some reason one to two bearing will be extremely shot like half the bearing is flattened and worn down, but all the rest still seem to be in spec. I'm not sure if it's caused by jumping or if those bearings got seized up for some reason? Where I see the most wear is on old BMX's is the bottom headset bearing is crushed and the top is fine from jumping.
Also you used to see a lot of bent axles in BMX I'm sure that might put some stress on the bearings

Ronsonic 

This may be an obsolete problem. BitD, tolerances weren't what they are now and producing a batch of bearings that matched to say, 25 millionths of an inch was easier than getting them to match a specific diameter within say ten times that. Because cup and cone set-ups get adjusted by hand the diameter of the balls could be way off and still work perfectly if properly adjusted.

I suspect that modern processes are much tighter for the overall diameter than decades ago when us old guys had to keep batches together.

bicyclridr4life

Nope.
On my bikes with caged and loose bearings, I clean them, put new grease in, and reassemble.
I only replace the bearings if I'm replacing the races and cones. That's how I was taught to do it.

In 55 plus years, I've never had a bearing fail doing it this way.

cannonride15

Well. no less an authority than the late Jobst Brandt had this to say about that:
https://yarchive.net/bike/ball_bearings.html

MarcusT

Unless pitted or damaged I have never replaced bearings and I pride myself on having the smoothest rolling hubs on the road.
I suppose this can fall into replacing cables, tires/ tubes, grips/tape. Usually, if they are in good condition they stay where they are.

DiegoFrogs

Not generally. I have had older bikes that I've taken hold of that had some that looked like acorns, and of course I replaced all in those bearings. I've also replaced some caged bearings with loose ones to help extend the life of some damaged races that I've discovered on acquisition of an older bike or two. But if everything looks and feels okay, then everything looks and feels okay. They're steel bearings, not prophylactics...

branko_76 

I restore a lot of low-end bikes road bikes from the 1970's (Raleigh Grand Prix, etc.) and for the most part re-use the old bearings. I recently purchased several sizes of Grade 25 ball bearings in quantities of 150 or so each for the occasion that I decide to replace the old bearings with new.

An excerpt from Parks website...

"The quality of bearing can be defined by various ratings, such as the rating of ball roundness. A high quality steel ball bearing is consider grade 25. The grade number refers to the tolerance per millionth of an inch. A grade 25 is accurate to 25/1,000,000 of an inch. Less expensive ball bearings may be grade 300, which are less round, at 300/1,000,000 of an inch."

This got me thinking, are the stock bearings on these old road bikes, even though not damaged, as good as new Grade 25 bearings? If not, then it seems to me that replacing the old bearings with those of higher quality would prolong the life of the bikes and in the long run be more environmentally friendly.

branko_76 

Thanks for posting that. The following interests me because I just bought some NOS wheels with Normandy Hubs and spinning them by hand, I could feel some grinding. Assuming the grease was dried, I took one hub apart and saw that the grease was fine. Could they have been adjusted that way in the factory intentionally?

From the link...Kirby Krieger writes:

> Back before the Internet, I and my biking buddies would spend no few
> moments perfecting the adjustment of the bearing surfaces on our
> bikes. We would make sure that wheels reversed direction four times
> before settling with the heaviest point at the bottom. We would
> pack our pedals carefully and be sure they had an effortless spin.
> My question is: was this silly?

Yes it was silly because bearings don't carry loads well without
preload. In the unloaded condition that you were adjusting, the fully
free ball bearing just barely makes contact. Under load the balls
under the axle sink into the race elastically, one at a time as they
pass. This is why you'll notice auto mechanics always adjust front
wheel bearings with preload. This must be done on differential gear
bearings. The most important place on a bicycle for preload is the BB
spindle of the conventional cup and cone type. The spindle should
turn with perceptible drag when rotated by thumb and forefinger...
about 4-5 oz-in torque.