Are there Two sizes of 1" Headset?

[Iwasgoodonce]

I have a recently acquired set of 531 forks to replace the crash damaged ones on my Graham Weigh. I cannot get the cup to fit over the race on the forks at the bottom of the steerer.
Are there two sizes? Or, maybe did the headset get knocked slightly oval in the crash?

Thanks.

 

[jinjrich]

Yes there are 2 different sizes. I've encountered this over the years in the workshop but I'm afraid i cant remember the exact difference. One might be an old euro size, the other English...I remember a chap at chicken cycle kit went through it with me years ago! Both still available i believe.

Edit: I seem to remember it came to light because the cups were too loose in the frame though, nothing to do with the crown race, which i just filed down.

 

[CassidyAce]

Re:

I've had this happen too. There is more than one size. Check here: https://www.sheldonbrown.com/cribsheet-headsets.html.

 

[RD-Dan]

There's more than two, I found this out when putting a new headset in a mid 80's Suntour Alpine geared Peugeot. The original headset was a Tange BMX one and the Shimano 600 cups were about 2mm too small to fit the headtube and the crown race was too big. I ended up grinding and polishing the bearing surfaces and re-using the original one.

 

[Iwasgoodonce]

Nothing is ever straight forwards is it? I find it hard to believe that a headset that came off the forks of a 531 Graham Weigh won't fit on to Dawes 531 forks?

Wouldn't they both be 1" ISO?

 

[RD-Dan]

You could remove some material from the seat with a file, I've done it before and it isn't very difficult. Just remember to do so slowly and carefully as you can't put the steel back on.

 

[droppedout]

you can't put the steel back on.

With jbweld or its pound shop equivalent you sort of can, kind of, so if the steerer gets worn through a slack headset it's not the end of the world

 

[Iwasgoodonce]

A bit of an update.

I reached for the cheap guestimator again and got these measurements:

Inner Diameter of the bottom headset race that goes on the forks = 26.30mm
That is a Richey Logic I just found in the loft.

Diameter of the metal it is supposed to go on = 26.80mm

The guestimator is probably not 100% accurate; it is a Clarke after all! I have measured a few times though. Half a poxy mm! That is only 0.25mm per side.

I have checked the threads and they seem to match. I just need to make it fit. I think I am going to file/sand the headset piece until it interference fits the forks. Before I do that, I'm going to make sure the other bits fit in the frame.

 

[legrandefromage]

stickem' in the freezer overnight

 

[Iwasgoodonce]

stickem' in the freezer overnight

Cheers Cheese.

I'm giving it a go. I have helped it along by taking a finishing file to any high spots and rust pitting. I can always take a Dremel to the headset ring as well.