Bicycle Mechanics - Preventive Bottom Bracket Replacement - Does it make sense?

My cyclocross bike came into the family in April. Many road miles till I got my road bike in October, it commutes to work in nice and in ugly weather, and actually goes and plays CX, too. In all likelihood, this bike will see 3-4000 miles by it's birthday next April.

Does it make sense to replace the bottom bracket as a preventive maintenance item, or wait until failure? This is the Performance Fuji Cross Comp build, with 105's using the FSA crankset and I think BB.

Since I ride this bike a lot - and will use it on group rides all winter, so it will still get a wide variety of ride type in different weather - I like the Chris King BB since it is designed to be easily serviced (the engineer in me likes the maintainability built in - the ability to easily re-grease seems to be a great idea).

It is kinda funny - been babying the new road bike and just riding the snot out of the CX bike, and just realized in my bike repair class at the LBS that it is really the everyday bike that needs the TLC to compensate for all of the ugly riding it sees (the ugliest riding being the simple fact that it is my butt in the saddle).

Does it make sense to replace the bottom bracket as a preventive maintenance item, or wait until failure?

I wouldn't replace a bottom bracket that was performing well but at the same time you don't have to wait for failure. Check your BB as part of regular maintenance, when you feel excessive play or grinding, replace it.

My cyclocross bike came into the family in April. Many road miles till I got my road bike in October, it commutes to work in nice and in ugly weather, and actually goes and plays CX, too. In all likelihood, this bike will see 3-4000 miles by it's birthday next April.

Does it make sense to replace the bottom bracket as a preventive maintenance item, or wait until failure? This is the Performance Fuji Cross Comp build, with 105's using the FSA crankset and I think BB.

Since I ride this bike a lot - and will use it on group rides all winter, so it will still get a wide variety of ride type in different weather - I like the Chris King BB since it is designed to be easily serviced (the engineer in me likes the maintainability built in - the ability to easily re-grease seems to be a great idea).

It is kinda funny - been babying the new road bike and just riding the snot out of the CX bike, and just realized in my bike repair class at the LBS that it is really the everyday bike that needs the TLC to compensate for all of the ugly riding it sees (the ugliest riding being the simple fact that it is my butt in the saddle).

I would wait until you feel some sort of reduction in performance, be that extra drag, grinding or movement in the cranks. Up to you though, if you want to get the King in there now, you won't do any harm.

I wouldn't replace a bottom bracket that was performing well but at the same time you don't have to wait for failure. Check your BB as part of regular maintenance, when you feel excessive play or grinding, replace it.

Beat me to it :D

Couldn't hurt to get your replacement part ahead of time to give you piece of mind. But if you're expecting it to wear out and it hasn't done so already, just keep going until it does!

If it is a "sealed" bottom bracket, there is nothing you can do to service it. Keep riding until you can feel it going, then replace. Two advantages of the old style cone and cup: easy to service and very inexpensive.

david58, I vote for buying a replacement BB and have it on hand for if/when the present one fails. If you want to replace it simply to erase any niggling doubts, go ahead as I bet many of us have done the same.

Brad

Ride the current on until it shows signs of distress. Bottom brackets don't fail catastrophically and leave you stranded unless the spindle snaps. Usually you get plenty of warning. Maybe the current one will disappoint you and last for years. :)

I can't see what there is to gain by "preventative" replacement. Unless you're planning a long tour, the only consequence of failure is that you'll have to replace the BB. Given that you might as wait until that happens. Also consider the season. You're heading into winter which is harder on BBs than spring and summer. Why subject a brand new BB to the harshest conditions.

Leave the old one in and cross your fingers that it makes it at least through the winter. Then again there's always the chance that it'll surprise you and you'll be facing this very same decision next November.

I have the same BB/crank on my '07 fuji cross pro. I'm somewhere around 4-5k and it was grinding a tiny bit, so +1 for having a replacement (and the BBT-19 tool) on hand. And related questions for hijack:

My old FSA BB had some green stuff on the drive-side threads, is that thread locker? I'm scraping it out best I can, would some mineral spirits be a good idea? WD-40 didn't do much.

The non-drive side I unscrewed by hand after breaking it free, nice and smooth (no green stuff). The drive-side I still needed the wrench, higher but consistent/smooth level of effort until it was nearly free. I'm assuming this is due to the green stuff and not that the threads have an issue?

New DA 7900 BB has green stuff on it, do I need to add anything else? Aluminum frame. My on-hand options are anti-seize (copper-based?), blue loctite, white lithium grease, teflon tape.

If you plan on upgrading to a Chris King, go ahead and replace it now. There's no point in squeezing the last mile out of the current BB when you want a better one. bk

Beware of Bike Forums cheap-think!

If it is a "sealed" bottom bracket, there is nothing you can do to service it.

It depends.

American Classic ISIS bottom brackets have replaceable cartridge bearings and buying a $10 pair of bearings beats bending over for a $100 bottom bracket.

I hear a man looking for an excuse to buy a CK BB. You should just do it - they are a thing of beauty - that is all the justification you need. You'll be wanting a CK grease injector too, and a grease gun to go with it. And some Phil Wood waterproof synthetic grease. Face and chase the shell when you fit it (Oh - you'll need a facing / chasing cutter - Icetoolz do an affordable one). All of this makes no economic sense at all. Enjoy! I did.

The engineer in you should say if it ain't broke don't fix it.

The engineer in you should say if it ain't broke don't fix it.

That's what I SAY. What do I DO? Well, sometimes I just want to buy my bike a present.

That's what I SAY. What do I DO? Well, sometimes I just want to buy my bike a present.
Me too. One way for the OP to justify the premature purchase of the CK bottom bracket is to buy and install it now while the OEM bottom bracket is still good. That way he can put the OEM parts away for emergency use if the CK ever needs to be sent back for warranty work or new bearings after many years. All of this assumes the crank will still be around by then.

Plenty of other parts on a bike are more likely to break or wear out before a BB. Might as well stock up on them first.

The origial question was (paraphrased) "Does it make sense to replace a functional BB as preventative maintenance?". The answer is "No" but that doesn't make it wrong for the OP to upgrade his BB just because he wants to or he is hoping for a slight improvement in performance. I've replaced several perfectly functional components just to see the difference, to try something new, or just because I like to wrench on stuff.