Bicycle Mechanics - Maintenance ~ Strategic VS Breakdown

I normally commute 75-100 km (50-60 miles) per week. I'm considering whether I should plan to disassemble my center bracket, clean and re-lubricate it as a preventative measure, or whether I should just ride until it starts to make noises. It's a cartridge type, 3 piece. As a child we would ride our bikes forever and I can't remember ever having reason to pull my cranks apart, except if I got a bike second hand which needed restoration. I've got all the latest tools and know how, so that's not the issue. But I'm not as enthusiastic as I used to be, so don't want to be doing excessive maintenance.

Opinions welcome......... ;-)

3 piece? Wtf?

What kind of cartridge bb is this?

If it's a cartridge BB, there's not much you can do to maintain it, and they generally don't need any maintenance. It'll last for a while, so just ride it until it's worn/needs replacing.

3 piece? Wtf?

What kind of cartridge bb is this?

By 3 piece, I mean each of the cranks can be separated from the shaft.
By cartridge, I mean that to rebuild it one does not have to buy a shaft and 2 cups and 2 dozen ball bearings. Rather, the ball bearings are pre-assembled. Like this one.........
http://bicycletutor.com/cartridge-bottom-bracket/

If it's a cartridge BB, there's not much you can do to maintain it, and they generally don't need any maintenance. It'll last for a while, so just ride it until it's worn/needs replacing.

Thanks Luke - Your answer makes sense!

Which of the following assemblies in a modern bike can I disassemble and re-grease, as opposed to the other type which have sealed bearings?
Front wheel.
Rear wheel.
Steering stem.

If my crank has sealed bearings, how well are they sealed? What if I frequently ride in the rain and give my bike a wash occasionally with a hose spray? Will water get into the sealed unit?

By 3 piece, I mean each of the cranks can be separated from the shaft.
By cartridge, I mean that to rebuild it one does not have to buy a shaft and 2 cups and 2 dozen ball bearings. Rather, the ball bearings are pre-assembled. Like this one.........
http://bicycletutor.com/cartridge-bottom-bracket/

You had me baffled as well since your terminology was incorrect... a 3 piece bottom bracket describes a cup and cone assembly and a cartridge describes a sealed unit which is what you seem to have. There is no such thing as cartridge crank arms.

A 3 piece bottom bracket only has 22 bearings (11 per side) if there is no bearing cage.

Most cranks can have the arms removed from the spindle unless you are dealing with an Ashtabula which has a one piece crank arm assembly.

Most cartridge bottom brackets cannot be serviced although removing it and putting a little grease on the threads to ensure nothing seizes is never a bad idea, especially if you are not aware of the bike's service history.

3 piece bottom brackets should get overhauled on a yearly basis or more frequently if the bike sees extreme use.

Which of the following assemblies in a modern bike can I disassemble and re-grease, as opposed to the other type which have sealed bearings?
Front wheel.
Rear wheel.
Steering stem.

If my crank has sealed bearings, how well are they sealed? What if I frequently ride in the rain and give my bike a wash occasionally with a hose spray? Will water get into the sealed unit?

Depends on how the bike is equipped... more and more bicycles are being fitted with cartridge bearings in the headset and hubs as these lower production costs, are nearly impervious to contamination, and servicing them and setting them up is much easier when they do need service.

If your bike has loose bearing assemblies in the headset and hubs these need to be serviced regularly and this is also dependent on use and environment... you should not be spraying water into any bearing assembly.

A decent cartridge bottom bracket can last 10's of thousands of kilometers and they are usually well sealed... a high quality 3 piece bb can outlast a cartridge system if it is properly maintained and set up.

Which of the following assemblies in a modern bike can I disassemble and re-grease, as opposed to the other type which have sealed bearings?
Front wheel.
Rear wheel.
Steering stem.

If my crank has sealed bearings, how well are they sealed? What if I frequently ride in the rain and give my bike a wash occasionally with a hose spray? Will water get into the sealed unit?

Well, you don't disassemble the wheels as such. It's the hubs which contain the bearings.

You can service hubs and the headset. Even if the headset has sealed cartridge bearings, you can pick the seals off and give them a pretty good clean, and re-pack them with some fresh grease.

In regards to the bottom bracket, they are very well sealed. As long as you don't use high-pressure water on the BB, and only use a relatively light setting on the hose, there shouldn't be an issue with that. Riding in the rain frequently may shorten the life of the BB, but it will still last a while. On top of that, they're pretty cheap and easy to replace.