New Stronglight threaded headset - wont fit 25.4mm steerer

[retromart]

I'm attempting to put a new headset on my 1988 falcon triathlon fork with 25.4mm threaded ISO steerer, and have just brought, and tried to fit, my second stronglight a9 headset, but both are just too tight to get more than 1.5-2 turns onto the thread. My 4 year old VP headset, another unused ACOR ( it was JIS which i hadnt realised) and the original OMAS, all screw on perfectly, so i really cant see whats gone wrong...

Both new headsets were supplied in boxes marked bsc and 251113, which is the correct item code for an english 1" thread , though Stronglight do make a 'french' threaded version. (which would be based on a 25.0mm steerer). Both headsets also came from different suppliers (presumably their own stock?)

measuring the internal threads of all the locknuts, there is about a 0.35mm smaller dia. on the new ones, so all I can think of is that Ive been sent french threaded versions by mistake - or have I missed something obvious? - could I really have been that unlucky to get the wrong part twice? Is Stronglights quality control a bit rubbish?

Any suggestions really appreciated, as this is holding up my bike rebuild (and getting a bit expensive) , so thanks in advance......

 

[Midlife]

Did you pay £14 or £35 for the headset?

1" threaded headsets are pretty standard and even Italian ones screw on, are you desperate for an A9? Something sounds wrong, have you got a spare 1" set of forks you could try them on...

Shaun

 

[Nob]

Re:

Sounds quite possibly you have a French threaded headset..or steerer

If you have a British threaded steel steerer you can force the alloy threaded parts down as the steel would act like a tap. I've done this in the past & it not a problem as only you will know when it's built.

 

[retromart]

Re:

Thanks for replies - I liked the look of the A9, and it matched the stack height nicely - and both cost just over £20, whereas frenc threaded seem to be a lot more, where available.

unfortunately, i have no spare fork, however, the 24tpi thread of a bottom bracket cup matches the steerer thread perfectly, and as my vernier gives a 25.32-25.42 steerer dia, it all points to the steerer being an english thread, which i would have expected as i got the frame and fork new in 1988.

My older omas headset is marked 1"x24, and I think would be a loose fit fit if I had a 25.0mm steerer.

If i could prove ive been sent a wrong size, i could send them back for refund, and tempting though it is, if i just wind the top cap and locknut on, and recut the threads, i'll be stuffed if if it didnt work for some reason...

So, probably next step will be either get hold of another old steerer, or drop in to a LBS... i'll post back if I ever resolve it!