# How Often Do You Replace Your Bottom Bracket?



## ssif21 (Sep 23, 2005)

Mine is five years old but only has about two years of riding (I was off the bike for three years due to medical problems). I did the remove-the-chain-and-spin-the-crank thing. Perfectly smooth. Any reason to replace it? Thanks.


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## Spunout (Aug 12, 2002)

No....


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## Anti-gravity (Jul 16, 2004)

ssif21 said:


> Mine is five years old but only has about two years of riding (I was off the bike for three years due to medical problems). I did the remove-the-chain-and-spin-the-crank thing. Perfectly smooth. Any reason to replace it? Thanks.


There's really no periodic time period for BB replacement. You run em till they die. If the bearings are smooth without any perceptable play, then they are fine. When things eventually get contaminated (if they ever do), then you'll notice roughness, crunchiness or significant play in the bearings. The BB is, of course a self-contained unit, so you can run it into the ground before replacing it. Ride and be happy!


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## ssif21 (Sep 23, 2005)

Anti-gravity said:


> When things eventually get contaminated (if they ever do), then you'll notice roughness, crunchiness or significant play in the bearings.


If I hear crunching the hard part will be figuring out whether it's my bottom bracket or my artificial knee! That thing pops like Chinese New Year.

To keep my mind occupied during a ride, I tried to calculate how many rotations the bottom bracket makes in a year. For me--limited by weather and work to about 9 months of the year and about 7 to 8 hours a week of seat time--I figured it's 1-3 million rotations per year. Pretty amazing for a $50 part.


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## Anti-gravity (Jul 16, 2004)

ssif21 said:


> If I hear crunching the hard part will be figuring out whether it's my bottom bracket or my artificial knee! That thing pops like Chinese New Year.
> 
> To keep my mind occupied during a ride, I tried to calculate how many rotations the bottom bracket makes in a year. For me--limited by weather and work to about 9 months of the year and about 7 to 8 hours a week of seat time--I figured it's 1-3 million rotations per year. Pretty amazing for a $50 part.


There are some people on this board that have gotten many 10s of thousands of miles on a single BB. Kerry Irons has gone through a few, getting as much as 70,000 on one IIRC. I think one was a cup and cone as well. AFAIK, he's pretty good about his maintenance!


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## Cory (Jan 29, 2004)

*Yet another maintenance-free component, for me*

I'll be the first to say I'm not as picky as I probably should be about maintenance, but in 30+ years of riding, about 20 of them semi-serious, I think I've serviced one or possibly two bottom brackets. It was a while ago, too, because both were old-school cup-and-cone style (now obsolete because, I guess, they were durable, cheap and easy to take care of). I'll probably tear down a couple this winter just because I've decided to go through all the bikes I ride a lot and make sure everything's right, but I don't see any signs of trouble.
For what it's worth, the BB in my singlespeed--a mid-'80s Trek I rode for years as my main bike, then converted with a BMX freewheel--has been lubed and adjusted once, after I bought the bike in 1994 from a guy who'd ridden it from Indiana to Reno, and it didn't need it then.


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## SDizzle (May 1, 2004)

Never. Unless you have one of the new, disposable generation...

I have 50-60k miles on a cup-n-cone Shimano 600, 30-40k on cup-n-cone Shimano Dura-Ace 7700, at least 45k on a Campy Chorus, and 5k mtb miles on a splined Shimano XT that's seen nothing but rigid singlespeed abuse. All are in great shape, except the XT, which is still far from being on its last legs.


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## Kerry Irons (Feb 25, 2002)

*Replacement vs. maintenance*

As others have said, if the unit turns smoothly without play, then there is no reason to replace it. And even if it has problems, continuing to ride it does no harm other than perhaps wasting a tiny bit of your pedalling effort. However, lots of people have gotten themselves into trouble by only checking to see if things turn smoothly. On some sort of regular basis, the BB should be removed from the frame, all frame and BB threads cleaned and greased, and then reassembleld. If you don't do this, you may find that when the unit does need to be replaced, you can't get it out of the frame because the threads have seized.


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## Toothpick (Oct 14, 2002)

Kerry Irons said:


> As others have said, if the unit turns smoothly without play, then there is no reason to replace it. And even if it has problems, continuing to ride it does no harm other than perhaps wasting a tiny bit of your pedalling effort. However, lots of people have gotten themselves into trouble by only checking to see if things turn smoothly. On some sort of regular basis, the BB should be removed from the frame, all frame and BB threads cleaned and greased, and then reassembleld. If you don't do this, you may find that when the unit does need to be replaced, you can't get it out of the frame because the threads have seized.


Not to highjack thread, but how many miles/often would the regular removal/clean/relube be done?


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## Kerry Irons (Feb 25, 2002)

*Frequency*



Toothpick said:


> Not to highjack thread, but how many miles/often would the regular removal/clean/relube be done?


Hard to say, since riding conditions can vary widely. I do it annually, but that is after several thousand miles, perhaps 4-5 seasons compared to many riders' annual mileage. My gut feel is at least every other year or annually if you do more than 5K miles per year. Experience will tell you whether you need to do it more often.


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## larsct (Feb 10, 2013)

Bottom brackets should be removed, cleaned, and threads re-greased on a time interval (annual) because grease degrades regardless of usage. Also, old grease will allow seals to dry and rot. If you ride a lot, then it should be done by mileage because dirt can work its way in. There are dust seals between the bearing and the crank arm, they should be removed, cleaned, and re-greased. Failure to do so will allow dirt and water to enter the sealed bearing sooner (learned this the hard way). That grease will create a protective barrier.


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## crossracer (Jun 21, 2004)

Yea, my experience is that not much grease is used on assembly of the bike, so five years, riding be darned, needs a good removal, clean, grease, and reinstall.

Glad you are back riding


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## cxwrench (Nov 9, 2004)

larsct said:


> Bottom brackets should be removed, cleaned, and threads re-greased on a time interval (annual) because grease degrades regardless of usage. Also, old grease will allow seals to dry and rot. If you ride a lot, then it should be done by mileage because dirt can work its way in. There are dust seals between the bearing and the crank arm, they should be removed, cleaned, and re-greased. Failure to do so will allow dirt and water to enter the sealed bearing sooner (learned this the hard way). That grease will create a protective barrier.


i have to ask...how on earth did you find this (over 7 year old) thread, and why did you feel the need to reply? good advice, though.


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## metoou2 (Mar 18, 2009)

It seems 'thread dredge' is becoming a past time for more than a few members. 
Creaky has done it for quite some time. 

I will hunt up a thread doing research, but hunting up a thread to then make a reply, mmmmmmmmm I dunno?


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