Singlespeed & Fixed Gear - headset/fork question

i searched. i couldn't find an answer. so im just gonna ask:

i have a miyata 912 im converting. i need a headset and a fork. am i looking for 1" or 1 1/8" if i am going threadless? its an old (80's) frame. i don't know much about steertube sizes or anything. can i even use a 1 1/8" fork and headset on an older frame? any help would be rad.

thanks.

i searched. i couldn't find an answer. so im just gonna ask:

i have a miyata 912 im converting. i need a headset and a fork. am i looking for 1" or 1 1/8" if i am going threadless? its an old (80's) frame. i don't know much about steertube sizes or anything. can i even use a 1 1/8" fork and headset on an older frame? any help would be rad.

thanks.

1" pretty much everything before '00 is one inch. You cannot use a 1 1/8" fork.

912s are really nice bikes. Do you have the fork for it? What size is the frame?

i don't have the fork for it unfourtunately. it's a 50cm frame. can i use a 1 1/8" headset with a shim on a 1" threadless fork?

the headset won't fit in the frame.

No, you need a 1" fork and headset, though both threaded and threadless are easy to find in this size. There are metric craptons of threads about which one is better and why, threaded is period correct and some people like the look, threadless is generally slightly easier to deal with and performs slightly better on a level I promise you'll never care about. If you don't have the fork you're going to need a shop or an experienced friend to get one that fits. Don't buy the headset until you have the fork.

The only thing that can be shimmed in the headset/stem system is a threadless stem, 1 1/8" stems are way more common so it's normal to use one of those and a shim on a 1" threadless steerer. This works perfectly fine and doesn't look ghetto at all.

hey, thanks a lot for the help dudes (or dudettes). i appreciate you clearing up a portion of my bike ignorance!