Your bicycle’s headtube must have an inside diameter of 44mm or larger in order to use any 1 1/4, 1 3/8, or 1 1/2 tapered forks. Traditional 1 1/8 in headtubes, or 34mm inside diameter headtubes, cannot accept a tapered fork, therefore we do not make an adapter that will allow you to use a tapered steering column on a traditional 1 1/8 in headtube. (Integrated "IS" 47 & 49 mm headtubes will not accept 1 1/2 tapered forks)
If you are unsure about the measurement of your bicycle’s headtube, you can consult our Standardized Headset Identification System (SHIS) or consult your favorite local bike shop.
Please note: Nominal insertion bore depth for 44mm head-tubes is 9mm. EC44/40 requires an insertion depth of 15mm. Park Tool Reamer 788 should be used with the supplied spacer to reach the 15mm bore depth for EC44/40 Bottoms.
For more details please head over to our tech article: "Everything you needs to know about headsets"