hi again i am building a principia tlc 650 time trial bike..Not being used for racing just building as i can not build anything else IE car/motorcycle it has a kestrel carbon ems 650fork .which has 1 inch steer tube..there is not a whole lot to chose from in 1 inch.. i have seen spacers to bump it up from 1 inch to the now a days standard 1 1/8 inch.are the spacers safe or do they tend to loosen up? thank you in advance for your time

Sorry, I can't spare enough time and effort to parse your post into an intelligible language.

I'm pretty sure that you're talking about a fork with a 1" steerer, and how it fits into a 1" threadless headset. If you're talking about fitting a modern stem on to the vintage fork, then I can help you.

You're correct; 1 1/8" is the more standard size currently (before you get to tapered steerers).

The adapter you need to use is a "steerer tube shim" to fit a 1 1/8" stem on to the 1" steerer tube. They're $5 at any bike shop. They come in two sizes, meant to fit inside either a 4 cm or 5 cm tall stem.

Steerer tube shims are safe to use; just make sure all the stem bolts and headset bolts are tight.

Of course, if you're talking about putting the fork with the 1" steerer into a frame meant for 1 1/8", then I can't help you. Headset adapters may exist; I have no experience with them.

sorry i guess i rambled a little..My bike has 1 inch steer tube.Head stems seem to be hard to find for this.I have seen bushings that widen the steering stem to 1 1/8 inches.Do these bushings work.or do they tend to loosen up.

Thank you Iowa.Sorry ankle works that i was not clearer with what i was saying.Yes Iowa i just want to expand my 1 inch tube to 1 1/8 as there is more of a selection available. I am not trying to put a 1 inch tube into a 1 1/8 frame

Do you want shims to swell the steerer tube at the stem clamp to 1 1/8"?
Or do you want spacers to mount an 1" headset in an 1 1/8" frame?
I've used the shims with no issues at all. And I've used spacers to reduce a headtube together with a regular external headset, also without issue. Never tried with an integrated headset though.

Just want to expand my 1 inch steer tube to 1 1/8 steer tube with shims I have seen.Iowa answered for me thank you. Newish at this bike lingo and have to state my questions clearer with proper wording.

Yes, a properly sized shim will work.

Proper wording is worth the extra effort.

Or do you mean these?: Universal Cycles -- Zoom Q Stem Adapters

no thank you though iowa got it right

No prob. That was the first explanation that came to mind, simply because I just finished a project where I had to use that shim. I put a 1 1/8" stem on a 1" steerer in order to mount some bars with a 31.8 clamp (90s MTB to drop bar conversion; a gravel bike for my GF).

Whenver I'm unsure of what terminology to use, I just look on SheldonBrown.com or any bike parts retailer to find the most common usage.

as for shims to adapt a 1-1/8" stem to a 1" steerer
they work perfectly
but you should ensure that the gap in the shim
lines up with the gap in the stem clamp
for maximum security