Giant overdrive 1, aka 1.25 to 1.125 tapered steerer. Would like to either fit 1.125 straight steerer or convert bearings or machine cup for 1.5 steerer fork. Doing this in order to fit some fork that will raise stack height. This is turning into a major pita. Have purchased 2 forks, one with a shorter than advertised steerer and a 1.5 the bearings of which DO NOT fit the 47mm receiver in the frame. I have spent 20 hours trying for a solution hence the custom bearing idea. This is fing stupid.

What model and year is the frame? Not enough information about the frame headset standard. https://problemsolversbike.com/produ...aptors_-_25047 will work if the lower cup is external.

If by stack you mean the BB center to the top tube/head tube center along the vertical then using a fork with a longer axle to crown or a lower stack of the headset is the way. But if you mean the bars height WRT the seat height then how long the steerer is (that otherwise fits the frame) is the way with a stem that raises enough (and not becomes too much reach). .

Which do you mean? Because of the terms and the various possible dimensions working directly with a shop that knows this stuff is the best way to not buy a 3rd fork that also isn't what you want. Andy

https://www.ebay.com/itm/Cane-Creek-...5.c10#viTabs_0

I think that's the right lower headtube reducer thingy. It says it's for Cannondale, but also says IS47, so 47mm should be the same as the Giant.

Thank you all so very much. So I ordered the Cannondale reducer from ebay. This will mean buying a 3rd fork. The bike is a 2011 Giant TCX medium size. This has become something of an odessey I refuse to give up on. I have lost 35 pounds riding this bike but am tired of the quasimodo riding position. I used a clamp style steerer extension and hated it; I bought FSA Gossamer cranks only to find out that winter salts seizes the pre-load bolt on the OEM cranks...so several hundred dollars latter and a fair amount of OCD has yielded the following: NOS TCX frame from Germany, large. Installed cranks, waited for 2.5mm spacer, now good. Ordered TCX carbon fork from "58cm" frame. This dude must have had this slammed cus this steerer is 240mm, like what I already had. Can't find another fork so I will buy a 1.125 steerer fork using the C'dale adapter, thank you. BTW, read that 1.5 forks would fit this frame so I have a 1.5/1.125 tapered headset waiting for a Vandessell carbon fork. 52mm integrated lower does NOT fit 47mm integrated head tube machining...ommfg! It, like me, is a work in progress. Found a bike I like and want to stick with it, canti's and all.