Paramount headset cups very loose

Peterc123

Retro Newbie
IMG_20230824_185537.jpg IMG_20230824_185528.jpg IMG_20230824_185455.jpg

Hi all, I am in the process of building a vintage road bike from the frame up. I just received this from eBay today. I strongly suspect it's a Paramount of Mansfield frame that's been repainted at some point. Campy dropouts, wrap over seat stays, drilled bb and the like. It's also nice and light at 1.9kg minus the forks. I removed the modernish 105 headset ready for it to be painted. Unfortunately the headset cups both top and bottom came out with very little effort, only a gentle pull with my fingers. I've tried another headset and the cups seemed the same I feel like a jolt would knock them out with no effort. Any ideas if this can be safely fixed? I have also noticed some wear to the threads on one side of the steerer tube, all parts of the headset thread on nicely though?
 
Is it possible that it's an ISO diameter headtube that's been fitted with a JIS standard headset?
I think that's entirely possible! I need some better calipers to measure the crown race, seems to be 27mm, but they are horrible plasticy calipers
 
Someone may have run the headset loose???? You can run a center punch around the headset cups (male part!!!) About 15 -20 times, more the better. This does make it a snugger fit, but as the gent said above could be the wrong headset to start with !!!!
 
Push the cups back in, do they feel tighter side to side and looser front to back? Head tubes usually ovalize front to back not side to side due to the forces they experience. I'd expect the wrong type of cups to be loose in all directions but more waggle front to back indicates stretching fore and aft in the headtube. Knurling, punching or epoxy on the cups interface will sort it. Or coke can shim to about rearmost 90deg of the cups.
Fork threads look good for another 100,000 miles as long as the headset is kept well adjusted.
 
Could be the headtube has flared out a tiny bit. Happened to one of my bikes with the exact same 105 headset. But it just fell out of its own accord.
 
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