Bicycle Mechanics - Crack in headset cup...problem?

Hello all,

I am a semi-noobie in the mechanics department. I've always done my own basic maintenance but never gone deeper, but now I am, so I've got some "stupid" questions.

Anyway, I've been using an old Schwinn Tempo as a backup commuter for about two years. It has 105 all around, with downtube shifting. There is a vertical crack in the bottom headset cup. I've ridden it this way for...um, maybe 1000 miles? There haven't been any noticable problems. What problems should I expect/look for? How urgently should I adress this? Finally can you replace just the cup (if you can find one)? Or do I have to replace the whole headset?

Thanks all!

one problem you will run into is moisture can and will get into the cup and rust the bearings and make the grease in there goes bad.you should replace the cup ,(not so easy to do.parts are hard to come by.), as soon you can. you will have to replace it as a set. sometime shops will have lose parts lazing around but not always.

From the location and direction of the crack, it seems to relatively harmless in that it won't strand you with and unridable bike. However, the headset should be replaced and parts are probably not available.

Assuming the bike has a 1" threaded headset, replacements are cheap. Nashbar offers a 1" cartridge bearing threaded headset for about $15 that is excellent for the price. I have one on a beater/rain bike that has lived through three years of water and abuse and is still in great shape.

Sorry for the double post. The forum wasn't responding when I posted the first one and I thought it didn't go through.