Gios Evolution with Austrian Headset Problem

[bg2]

Gios Frame with mannessman Oria tubing

the headset is proving to be a nightmare - i can't find a headset anywhere.

I have a shimano 105 HP-5500 headset that is incomplete and it fits both the thread and the head tube, so it must be an irregular size. However there's no i.d. on the headset. It's missing a lock nut and a spacer ring.

Any ideas ?

and before anyone suggests shimming a 1", i'd rather not go down that route.

thanks

 

[Stempie]

If your headset doesn't fit, the head tube might be stretched. If that is the case, shimming it is probably the only way to be able to use the frame. I don't remember the threads on GIOS frames to be different from other brands. Maybe you can try another headset to see if the threads inside the headset are possibly corrupted. Another solution might to have the treads on the forks cut.

 

[Johnsqual]

Re:

I vaguely remember reading somewhere that Japanese ISO headsets (not JIS) were
a little bit bigger than normal ISO. Apparently the difference is enough to crack an
aluminium ALAN frame's lugs, for example :facepalm:

That might be why the Shimano headset seems to fit better - unfortunately I can't seem to find the link to where I read this...

I also vaguely remember that Chris King makes both headsets with extra long cup tubes
(but maybe only for MTBs) and headsets with a slightly bigger diameter to deal with slightly oversized headtubes. Probably best to contact them directly.

 

[stringfellow1946]

Try your headset on another pair of english/italian threaded forks to see if fits them OK. If it doesn't then maybe your headset is French threaded?
just a suggestion!!

 

[bg2]

Re:

I think it's more likely to be something to do with the German tubing. since one headset fits and another doesn't ....
Interesting re. Japanese ISO....