Originally Posted by
Redshift96
Seems to me that taking roughly 2mm - 2.5mm off of the meat of the steerer shaft should still leave it well within the safety margin in terms of durability (though i don't have the specific fork in hand yet, so can't measure the ID of the shaft to be sure of the resultant wall thickness.) Obviously this would need to be done by a competent shop, with an eye kept on avoiding overheating of the shaft and affecting the aluminum/carbon bond. And careful attention to the surfaces and radius of the race seat and crown face.
Any other reasons to avoid this approach? (I understand that it's easier/simpler/cheaper to buy an appropriate fork, but in this case I'm highly motivated to use this particular fork if I can find any way to make it work.
Originally Posted by
dabac
IME, a 1 1/8” steerer can pass through an 1” head tube.
I’ve made adapters that fit on the outside of the steerer tube to allow the installation of 1/18” headset cups ”outboard” of the original bearing mount.
it does change the geometry somewhat, but is generally manageable.
I wouldn't try making a 1" out of 1 1/8". Keep in mind nothing is solid, so if you're cutting off say 1/16" from the walls, there won't be anything left.
Now, one possibility would be to sleeve it. I.E. Find a tight fitting carbon fiber or aluminum tube, epoxy in place, and machine down as you desire. Make sure the tube extends far enough down to be pinned with the brake caliper.
As @
dabac suggested, the 1 1/8" fork may barely fit inside the 1" head tube. So if you made custom 1 1/8" bearing seats, it may work.
I'm wondering if some of the BMX kids making the conversion mentioned earlier simply added upper and lower thrust bearings, inserted the fork greased the tube.
My preference, however, would be to hunt down the correct part.
Kestrel 1" fork:
https://www.ebay.com/itm/402902625039
Profile Designs 1" fork:
https://www.ebay.com/itm/164781471339
Or, even get a steel fork made to your specs.