Installing/Buying a new fork/headset
 

Hi all. I bought a Fausto Coppi K14 Aluminum frame off ebay a few months back and I'm beginning to build it up. It does not have a fork or headset. I had a few questions before I start ordering parts. I measured the head tube and it appears to be rougly 1 1/4 inches. When buying a new fork do i buy 1 1/8th threadless and 1 1/8th headsets?

Hi welcome to the forums. you best bet is to eaither contact the manufacturer, a shop that sells these or the seller. it is very likely that it will take a 1 1/8" HS but there are so many variables here. can you post a few pics? is the ends of the HT flared? maybe it takes a hidden style headset.

Thanks for the tips. It's not flared it's just flat. I'll take some pics when i get home. Unfortunately the manufacturer is in italy and the seller is long gone. It looks pretty standard to me I just want to make sure i have the correct dimensions.

I think you need to be a little more precise/accurate with your measurement. Look at the Sheldon Brown site and you'll find a chart which explains the dimensions of various headset options. None of these is close to 1 1/4".

Probably if you measure carefully you will find that the inside diameter of the head tube is about 34.0 mm which is the diameter of the cups for a 1 1/8" headset. But then, a standard 1" headset has a cup diameter of 30.2mm, which is closer to 1 1/4", so maybe that's what you have.

Anyway, in all probability , you need either a 1" fork and headset or a 1 1/8" fork and headset. The 1" will measure about 30.2mm and the 1 1/8" will measure about 34mm. That is not a subtle difference so it shouldn't be hard to measure and decide. If you find it to be 34mm, then you are pretty much limited to threadless 1 1/8" headsets and forks. If it's about 30.2mm, then you can go either threadless or threaded. Most folks would probably go threadless but it depends on what you like. Either would work just fine. You might consider taking the frame to an LBS and buying an appropriate headset and having them install it. Many LBSs will install a purchased headset for free -- of course, it's not really free. Then you know what fork to buy and can either have the crown race installed or do it yourself.

Just for reference, these days accurate vernier style calipers with a digital readout are available for not much money at all. Even cheap ones will allow you to measure to .1 to .2 mm accuracy. If you do much bike maintenance at all, you will find them very handy very frequently.

If the ID of a non-integrated HS head tube is slightly over 1-1/4" (34mm) then it takes a 1-1/8 headset. Here's a link to headset dimensions for your reference.

The decision threaded or threadless is independent of the frame, and depends on the fork and type of stem used, though availability of threaded 1-1/8 forks and parts for them is extremely limited these days.

BTW- you don't need precision measuring tools, because there's only one size in this range to worry about.

No, for this problem, you don't need precise measuring tools though you need to tell the difference between 30.2 mm (about 1 3/16") and 34 mm(about 1 5/8") neither of which is close to 1 1/4". If you're trying to measure for a headset and you can't get closer than 1/16", then you need to measure more precisely. If you do much bike maintenance, then the ability to tell the difference between 3/16" balls and 1/4" balls may become important. If your current tools don't allow you to tell the difference between 30.2 mm and 34 mm with ease (about 1 3/16" and 1 5/8"), then an inexpensive and precise tool may be useful.

Thanks for the help. I went home and measured more carefully. It is indeed made for a 1 1/8th inch fork/headset.