Bicycle Mechanics - quill adapter

i have a question regarding quill adapters.

i have an old nishiki 10 speed that i'm converting to a single speed.

i've been looking to buy an threadless adapter so that i can use the stem and handlebars that i already have lying around.

i think i need a 7/8" : 1 1/8" adapter. but the only adapters i can seem to find online are 1" : 1 1/8".

am i measuring wrong, or is there something i'm failing to consider?

I'm pretty sure you're all set. The quill measures 7/8", but it's for a 1" headset. If you get the 1" to 1 1/8" adapter, it should work fine.

i bought and tried a 1" : 1 1/8" adapter, but it doesn't fit.
i started searching for smaller sizes after that.

i suspect that you're right about it being the right size. i'm assuming the problem is with me, not the adapter.

do i have to take the whole headset apart? i was thinking i could just put the adapter in and be done.

A 1":1-1/8" adapter should have worked. You don't need to take anything apart. Maybe you actually have a 1-1/8":1-1/8".

FYI, The measurement refers to the inner diameter of the headset and outer diameter of the steerer tube. But, since quill stems go into steerer tubes (and not around them like threadless stems), they have a 1/8" smaller outer diameter.

Measure the quill of your adapter; is it 7/8" (22.2 mm) or 1" (25.4 mm)? Should be 7/8".

Edit: Also measure the hole at the top of the headset, should also be 7/8".

A 1":1-1/8" adapter should have worked. You don't need to take anything apart. Maybe you actually have a 1-1/8":1-1/8".

FYI, The measurement refers to the inner diameter of the headset and outer diameter of the steerer tube. But, since quill stems go into steerer tubes (and not around them like threadless stems), they have a 1/8" smaller outer diameter.

Measure the quill of your adapter; is it 7/8" (22.2 mm) or 1" (25.4 mm)? Should be 7/8".

Wouldn't it be the ID of the steerer tube, not the headset?

Road Fan

Wouldn't it be the ID of the steerer tube, not the headset?

Road Fan

No, the steerer tube OD = headset ID. Otherwise, there'd be no contact. On modern, threadless systems, the ID of the steerer tube is inconsequential. For older, threaded/quill systems, it is 1/8" smaller (to account for the thickness of the steerer tube), and this equals the OD of the quill.

Wouldn't it be the ID of the steerer tube, not the headset?

Road Fan

You would think so, but no.

A 1" threaded headset uses a quill stem that measures 7/8"... And some slightly different oddball sizes if you are dealing with some bikes, specifically many Schwinns and old French bikes.

http://sheldonbrown.com/gloss_ha-i.html#headset

Scroll down to " Headset sizing ".

There is a smaller 1" steerer that uses a 21.1mm quill. Those were the ban of my existence at Marriott thanks to Sea Island Service from Charleston, SC and only really inept manager.

You would think so, but no.

A 1" threaded headset uses a quill stem that measures 7/8"... And some slightly different oddball sizes if you are dealing with some bikes, specifically many Schwinns and old French bikes.

And, I think, really old Giant road frames (which are probably Schwinns in disguise). I struck problem this recently, and the bike remains in bits because I just can't be bothered.