Main bearings

[loulou40]

Hi, can someone tell me how long or how many kilometers new bearings should last??

[ldrcycles]

Wheel bearings? Cranks, headset, pedal bearings?

[Duck!]

How long is a piece of string?

Bearing life is affected by the quality and type of bearings, location in the bike (not all bearings are equally loaded) and attention to maintenance.

[silentbutdeadly]

Four chains and a furlong. That should adequately answer all the above.