I have a Trek Domane 4.0 with about 6000 miles logged on it. I noticed today getting hard to spin. Got home and on the stand an sure enough feeling resistance when I spin the crank by hand which tells me bottom bracket again. This will be the 3rd replacement of bearings since purchased new. It has an integrated BB 90 which is simple to do since it is basically just replacing bearings. Since I still consider myself a newbie I'm wondering if this is the normal life expectancy for these bearings and is there anything I can do the extend the life. Thanks.

This question seems to be asked every week, 6000 miles for 3 sets of bearing sounds like you have done really well with them.

The bearings aren't that expensive TREK MADONE BOTTOM BRACKET BEARINGS, would invest in a puller/install tools if you haven't already, so you can replace as and when needed

If 2,000 miles on a set of BB bearings is par for the course, it's pretty pathetic.

IMO- anything less than 10,000 miles on a set of bearings is premature failure. And that's being very conservative. It's not rare at all for folks riding older sq. taper cup/cone bearings to see 50,000+ miles of BB life, so this is the benchmark against which the "superior" new and improved" designs should be compared against.

Granted, thatthe improvements in lower weight and ease of service, might be a trade off for shorter bearing life, but 2,000 miles is crazy.

Try to determine why you're seeing this poor service, be it spindle deflection, weather/rust, lack of lubrication, or whatever and see if you can address it and get some kind of reasonable service life. Of course, if you're willing to see BB bearing life shorter than chain life, it's your call.

From the Bleachers.. BB External bearings are just out there in the road spew from the front wheel

and people who buy Domanes hate Mudguard esthetics that may reduce that spray from the front wheel ..

maybe the old Patent holders at Wilderness Trail Bikes will licence some one to let the Grease Guard pump thru and purge zirk fitting
be used in external bearings , like they did with square taper BBs and licensed to Sun Tour decades ago..

just a Thought..

If I had to replace any bearing every 2K or so, even $4-5 a set loose balls, I'd find it unacceptable just on the hassle of redoing it.

Contamination is almost certainly the cause of failure here; that'll be what's killed a cartridge bearing early 99.5% of the time.

There might be a spot you can jam some appropriately-sized O-rings to help with that.

i agree. worn out at 2000 miles is, IME, is hard to believe. and i'll bet, if you were to as Trek what they thought the life expectancy of the BB bearings would be, and let them know that it was important to you, i wouldn't be surprised that they would say 10,000 miles or more. just my opinion. i've never had to replace any BB's on any of my bikes in 35 years of adult cycling. and i ride a lot, including a lot of touring.

so i would have to guess that if your BB bearings really have to be replaced and you haven't been misdiagnosing things, that either, as has been mentioned, there has been some contamination from water of salt or sand or a combination of them, or possibly an error in installation and/or adjustment. good luck, i hope you figure out the cause of the problem.

2000 miles on a bottom bracket is nowhere near normal. I'm thinking the installer is putting too much preload on the bearings and causing premature wear. They only need enough preload to remove side play in the spindle, any more and you're reducing your bearing life.

Thanks guys for the replies. My LBS did the first replacement. They showed me the bearings and it was evident there was moisture. I did the second replacement and also found moisture inside the BB. Same going on with the 3rd. I have no idea where the moisture is coming from. I don't ride in the rain and the bike lives in my shop when not being ridden. The integrated bb on this bike is basically bearings that press into the frame. You can install the bearing without using a press but I use one to keep them going in evenly. There is a thin rubber seal that covers the bearings between the frame and crank/chain ring. The seal doesn't press in so makes me wonder how much good it really does. The moisture seems to always be affecting the non drive side bearing. Guess I just need to stock up on bearing.

That's not normal at all as I think you now know. I was going to suggest better maintenance for the bearings but if they are trashed in 2000 miles...wow...I concur that too much preload or something odd is happening if you aren't riding in horrific weather conditions. I would agree that in your case I'd get a puller and get used to installing new bearings but having said that, something is amiss. You should be getting closer to 10,000 miles. I have about 7 bikes and have never seen a bike get less than 10,000 mi on a set of bearings. I'm sure it happens but not to me.

You Live in a Humid, near tropical, part of the country and are never very far from the Ocean, and you wonder where the moisture comes from?

Read that aloud to yourself ..

Water in frames is a common issue, especially because so many makers don't believe in drilling weep holes in the BB shell.

The shop on spotting the water/rust damage should have invested some effort at identifying a cause. The most common, is water entry via the seat tube (hence the need for drainage). Rear wheel spray hits the seat post or seat tube slot in the back of the frame and migrates down. I commonly find water damage from the inside out as evidenced by corrosion at the innermost end of threaded BB lockring and the like.

If your bike lacks a weep hole, but has a screwed on guide, you have some choices. My preference is to drill a hole under the guide, and carve a channel in the back (frame side) of the guide, leading out the back. Or you can possibly drill out a screw so it serves as a weephole, or use double sticky tape for the guide and let the screw hole be the weep hole.

I can't say whether your issue is wter through the seat tube since I can't see the damage, but it's something to consider, especially since you don't ride in the wet.

Also, if it's possible to remove the bearing seals and inject a quality waterproof baring grease (look for "marine grade") do so.

agree,, I've used Bearing Grease for Boat Trailer hubs for a Long Time.

because of course the boat , to float off the trailer, the wheels , have to be fully submerged.

[QUOTE=FBinNY;17619468]Water in frames is a common issue, especially because so many makers don't believe in drilling weep holes in the BB shell.

If your bike lacks a weep hole, but has a screwed on guide, you have some choices. My preference is to drill a hole under the guide, and carve a channel in the back (frame side) of the guide, leading out the back. Or you can possibly drill out a screw so it serves as a weephole, or use double sticky tape for the guide and let the screw hole be the weep hole.


Does not have a weep hole. I have looked. I like the idea of drilling a weep hole under the cable guide but have no experience with carbon. Any suggestions for drilling?

Marine grade grease is easily obtainable in these parts.

Thanks

That's what I told LBS with the first replacement. Smart a## mechanic there asked me if I was riding it in the ocean. I've learned to do most of my own work since then.

But just realize things are different in Arizona... I would, since you have some removed past Bearings ,

use them to get the overpacking the bearings with boat trailer wheel bearing Grease practice down,

so you can keep them better lubricated in regular service intervals, as the place you live obviously requires It.

This an External bearing type BB?

Any chance when it is hot out, your bike is cold from air conditioning inside causing sweat effect on metal parts once you go outside to ride? This combined with salt in air might do it ?

2000 miles average on a set of bottom bracket bearings is appalling. I currently have almost 7000 miles on one set of 6700 HTII bearings and almost 5000 miles on a second set and neither are anywhere near replacement. Something is dreadfully wrong with the OP's frame or dealer.

Good chance on that. When I get out moisture forms on the frame. Would make sense it would do it internally as well.

start saving the little silica gel packets from stuff and throw a couple in the BB next time you change it