I will definitely keep everyone posted. Specialized was quick to dismiss this as an option, but I have a feeling that it will work. If so I will give the part number, price, etc., and any other notes my mechanic comes up with. If you ever get that part figured out let me know. If the spacer that Specialized sends me doesn't work for whatever reason I am sure you can use the measurements to easily make your own part (45* chamfer, X inner diameter, X outer diameter, X thickness, etc.).

For the record here is their adapter:


Fingers crossed

can't you make an adapter that goes on top of the lower bearing?
so then you have a cool, light fork - crown race - bearing - adapter - frame
i would not modify the head tube, and also i'd stay with tapered steerer, since every bit of stiffness for steering and against brake chatter is welcome...

That's the purpose of the adapter that is pictured above. The idea would be to have the same unmodified headtube, a spacer pushing down the bearing, the bearing itself, then the crown race on top of the fork. As long as the chamfer and the thickness are the same we should be in good shape.

didn't really read all the other posts about the adapters, sorry;-)
some friends have that bike, looks like a nice one...

Wow. Just wow....

Edit: looks like someone cleaned out the insane post above this one, lol

How is this story unfolding? I ask because I am in the market for a new CX bike.

Sorry about the delay on this, but here's an update. I placed the order with the shop a little over 2 weeks ago and it took about 2 weeks to get the adapter in. My initial measurement of the adapter is about 11mm tall, but it has a section of it beveled out on the inside to accommodate the angle of the lower bearing (so that they sandwich together nicely).

With the adapter and bearing in the headtube I was still 3mm short of making good contact with the crown race. The only solution at this point is to use a small spacer under the crown race to make it work. Normally I wouldn't do it, but 3mm isn't very much (especially given how much of this particular fork is tapered) and I am using good aluminum.

The next issue is finding a washer that will work. We thought about it for a while and ended up cutting off a piece of the crown race setting tool to actually make it work. It had the perfect inner and outer diameter and is really good anodized aluminum. It took quite a few tries and cuts to get the material off, so needless to say the cut isn't very clean.

Tomorrow we will be grinding and fixing the spacer and putting it all together. I will take photos of everything, including the old fork, new fork, spacer, adapter from Specialized, the headtube, and how it all goes together. I will also try to get weights of individual pieces and the final product, as well as the inner diameter, outer diameter, and height of the spacer and Specialized adapter.

I hope this helps someone. Suffice it to say this hasn't been an easy or stress-free project, but it will be worth it in the end.

Which fork are you using?
Is there any possibility you could pick up the 3mm needed from, say, Pro-Bolt or perhaps even your local hardware store?

With all that effort I'm wondering if it'll be easier to replicate the lower-spacer afterall, keeping the bearing at the original height?
I may need to revisit that project.

Keep us posted, and thanks man!

_________________
Exp001

just an fyi, i came across some 1.5" bearing oddness just yesterday. it seems the cannondale and specialized 1.5" bearings are taller than, say, a Cane Creek bearing. i didnt measure the difference, so i can't say for certain it's 3mm difference, but it is a couple.

I contacted Specialized over the bearings and got this response:

Top: SHIS:IS41 - 1-1/8" Cane Creek Integrated Threadless
Bottom: SHIS:IS52/40 - 1.5" Integrated (IS)

Hope that helps

I am using an Easton EC90 SL Taper fork. I was going to check with a few places to see, but then we figured that we could use a piece of the crown race setting tool to make it work. I thought about just putting 10mm of material on the fork crown, but then again I didn't want to risk mounting that crown race too high up on the fork (which is something Specialized does anyways). This way we bring the bearing down a bit and raise the crown race up a bit.

I'm gonna head to the LBS now and see what's going on. Perhaps I'll come back with some photos, too.

Thanks for the tip! I have heard that Cannondale makes a bit of a thicker lower bearing, so that's always an option too.

Thanks, that's a HUGE help. I hate how many standards there are across the industry. For the record the guys at Chris King were super helpful and the guys at Cane Creek not so much.

i measured the cane creek bearing and one that i think came from a cannondale. the difference? just 0.6mm, so almost like no difference at all...