Hmmm, headset cups won't fit....

94 hei hei frame with brand new control centre headset and the cups are too big for the head tube by half a mm, thought this would go straight in!?

Have you tried shouting at it? sometimes helps

some recommend freezing the cups before installation

I wouldn't want to force headset cups in, or freeze them then they expand and crack the head tube.

Some headsets are bigger or smaller than advertised due to tolerances in manufacturing.

Do you have another you can try to see if it is the headset or head tube?

Unusual....any quality headset should comfortably fit Just a heads up, dont forget to use the correct installation inserts for fitting a CK headset to protect the cups from being crushed. Sometimes if you fit a used headset that has been brutally fitted/removed with the wrong tools by the previous owner, they can be off spec. Had to send a few back off the bay.

I thought CK press adapters fitted against the cups to protect the bearings!?

There can be a big difference between brands as far as fit. Some will almost drop into the headtube while others will never go. Headtubes can vary too obviously and with the two combined you need to find the right combo.

Dont risk cracking the frame, not for the sake of a £50 headset

mark

Yes I agree not worth the risk but frustrating all the same, if any headset should fit it would be the Kona control centre into a Kona frame.

Half a mm sounds like a lot too much; something is wrong in a big way. It's time to (relatively) accurately measure ID of the head tube, and OD of the headset to work out which bit is not what it's supposed to be.

If you try forcing it in, you'll break one, the other, or both. A "press fit" is H7/p6, which is to say that the "hole" should be on nominal diameter or up to 25 microns oversize, the "shaft" should be between 26 and 42 microns over nominal diameter for that diameter range- that's ~1/20mm *maximum* difference, or "just about discernible with a decent set of vernier calipers* if you're lucky, you really need a (very) expensive micron-level micrometer to get a decent reading". If you can see the size difference, something is wrong.

* yeah, chinese electronic calipers claim 1/100mm resolution, but their jaws can be off spec by over 1/10mm...

Think I need to take it to see a specialist

JIS/ISO standard differences maybe?