Headset/quill/stem sizing question.
 

I've got a HP-6207 Shimano headset (see http://www.velobase.com/ViewSingleCo...0-87AA450432FC )

I need to buy a new stem for it - the one I have is a 1piece and the clamp bolt stripped out the hole in the stem. I'm going to buy a quill adapter so I can buy a threadless stem - but I need to figure out what diameter I need to look for. Existing stem says '90' 'ITM' and 'Italy' on one side - which makes me think it's 90mm long and made by ITM. Other side has a stamp that says '85' which I'm assuming is the year. That's all I know of it though.

VeloBase says 'Available Threading: 25.4mm' for the italian one (which this is).

My plan is to replace it with one of these:

http://www.universalcycles.com/shopp...s.php?id=23897

and one of these:

http://www.universalcycles.com/shopp...s.php?id=16590

Will that quill adapter at the (1-1/8" fork) to 28.6mm (1-1/8" threadless stem) fit my headset - and then will that adjustable stem fit that adapter?

Everyone seems to have a different name for each dimension.

Also - any reco's on a better adapter and stem are appreciated. I'm not looking to drop a while bunch of cash - but $50 for the setup wouldn't be out of the question. I'd replace it with a one-piece w/clamp again except that it's all taped and wrapped so I'd rather not take it all apart and re-tape it again.

Holy *..... didn't even know such a thing was available, so thank you for educating me.

OK, back to the OP's question, now I'm interested too.

You have a 1" steerer. You want the 22.2mm adapter (the inside diameter of a 1" threaded steerer). The adapters you linked adapt to a 1 1/8" (28.6mm) threadless stem. The adjustable stem you linked to is for 1 1/8" steerer, but comes with a shim for 1" steerer which you won't need. You must get the stem with a bar clamp diameter that matches your bars.

That Zoom Q comes in 2 sizes, so I'll grab the 1" one.

Bars are original italian equipment - mid-80's - according to sheldonbrown.com should be 26.0mm - which is what that adjustable stem fits.

Thanks for the help - I'm loving this place already!