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Sealed Bearings

OK, wheel bearings are now sealed. How often should bearings be replace?

Replace them when they get noisey is all. Some cars I never replaced any in 3-500K. Another went at 20K and another car I replaced both front ones at 120K. Just never can tell.

there is no time frame to replace sealed bearings, but there is a recommended way to change them such as when one side goes bad replace the other. You do not have to replace all 4 at once if you have back ones. Just make sure that when you hear a roaring noise that you dont just rush out and get bearings replaced cause it could be a tire with broken belts that could be causing the noise.

Agree with above posters; replace them when they give trouble. We sold a 1994 Nissan Sentra last August wth over 150,000 miles on it. The bearings were OK and had never been replaced.

Bought a bicycle yesterday-Giant, Cromolly, triggered shifters, straight wheels, good paint, gears show moderate wear-which I suspect has been changed since this bike is cira 1985+/- 10 years.

So if bearings are sealed, I shouldn’t need to change the bottom bracket bearings if all is quiet and smooth-Correct?

Are sealed bearing used in bicycles now? In wheels, cranks, forks, or all assemblies. I have repaired a few of the Chinese bikes, both coaster and derailer, both had the traditional caged ball bearings.

what I mean is, Bearings are sealed in the bottom bracket. I haven’t taken this bike apart yet because I just bought it at GW-really cheap.

I thought you were talking cars. I haven’t worked on a bike in 50 plus years. They never used sealed bearings then.

I started seeing sealed hub and bot-bracket bearings in high-end bikes in the early '80s.
Now they’re in all but the cheapest.

http://www.sheldonbrown.com/gloss_ca-g.html#cartridge

No doubt the bikes that I see are the cheapest. But a shot of 90W on each bearing assembly will usually keep them going until the free wheeler or derailer fails. Chinese 18 speed “mountain” bikes can be bought for less than $60 locally. They are store returns that the buyers attempted to assemble but somehow missed a few details and returned them as defective.

I’ve had sealed wheel bearings in my own autos last a long distance, over 200K and still going, and others only a short distance, less than 35 k miles. I’ve always thought what damages sealed auto wheel bearings – and explains the wide variability in how long they are reported to last – is the occassional severe shock they get from the car hitting unseen potholes etc and the suspension bottoming out. If they really take a whack, the damage done will eventually show up with the typical growl. Avoiding running over road obstructions at high speed is probably about as good as you can do to keep your wheel bearings working.

I sort of prefer non-sealed wheel bearings actually. I never found the routine maintenance of lubing non-sealed bearings much of a burden. If I could buy a car with non-sealed wheel bearings, the kind where you remove the bearing, lube in by putting a dab of wheel grease in your hand then working the lube into the insides of the bearing, I’d prefer that type. But alas, I don’t think new cars come with the unsealed bearings any longer.

Two ways to deal with bike bearings. First, if you have an older bike and they are not sealed. , you can disassemble the crank or hub or pedal or headset…where ever you want, remove the bearings in races, clean and repack. . But, IMHO, because it’s not as critical as a car, you can leave them alone. They won’t overheat and seize up like a car, they will just become annoyingly loose and you can’t seem to tighten the hub sufficiently…then .it’s time to replace. There are bearings everywhere it seems in a bike. Back when I was touring, I repacked them every year. Life is too short.

@dogosa, I think I’ll take that advice and others…unless bottom bracket Klics or Klacs, I will leave it alone. The bearings have been changed at least once because it has the newer style locking nut.

II really haven’t examine the bike yet… Loaded it into the trunk of my 99Civic. Got out of the parking lot to the cornor, where the car coughed and died. Chance or sentinent wheeled Christines? So far this bike has cost me the purchase of $12, plus $18 taxi, plus repair of car. ;>{{
The tow is paid by insurance- which I was thinking about dropping.

Well longprime, since it’s a “new to you” bicycle, why not get it running “tip-top” before riding weather hits?

Also, this way you’ll become sufficiently educated about the workings of your bicycle that you can handle roadside breakdowns when they inevitably occur.

@meanjoe75an
It’s always riding weather in the PNW. Some are wetter than others, west of the Cascades.
I would if I could, but the bike is in the trunk of That car. :<{{

I’m convinced that the single most major factor on how long modern wheel bearings last is potholes. And how well you can avoid them. They can destroy even a young bearing set, and not hitting any can allow bearings to last indefinitely.

Bottom bracket hearings do not need to be changed until the crank becomes loose, the bearings become noisy, or the crank turning effort becomes uneven/inconsistant. My bikes had nonsealed bearings, and I used to creank and regrease them no less than annually, but I also did a lot of bad weather riding. Slogging through mud puddles IMHO justifies extra maintenance.

Speaking of bicycle bearings, long ago bicycle hubs and cranks had oil cups to make lubricating them easy. But at that time automobile generators, distributors and even water pumps often had the oil cups.