# DIY Tapered Headtube Mod Project



## shibiwan (Sep 2, 2012)

I 've been building up my bike and upgrading bits as I went along. I finally decided to mod the headtube on my 07 S-Works SJ FSR so that it'll work with a tapered fork since it was limiting my choices on the forks available these days.

Started out with this (uses a standard straight steerer fork, with a Specialized Mindset headset)









Removed the bottom Mindset HS bearing, and enlarged the angled headtube bearing seat to so that the fork could fit in the bottom. Went off to design and make a headset adaptor so I could fit a IS52 lower bearing at the bottom.









Installed the headset and bearing into my frame (press fit and also bonded in place to the existing headtube with JB Weld).

















Tested it out to see if it works properly









Took everything apart, sanded down the gel coat of the frame to the bare carbon fiber.









Laid up a mix of 12K linear tow and 2x2 twill, using filament winding technique. Wrapped up for compression and let it cure overnight









Cured in the morning









Sanded it down









Applied a couple resin topcoats









Wet sanded.....









Two rubbing compounds and UV wax later....









All done!


















Hope this gives you guys ideas on what you can get away with for carbon frames.

-S


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## shibiwan (Sep 2, 2012)

Oh... and the bike is still within design specs. The HTA is down to 69 degrees and that is still within the Specialized design specs (69-71 deg).

-S


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## Walt (Jan 23, 2004)

*Wow*

That bike does not look like it fits you at *all*.

Neat project!

-W


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## pvd (Jan 4, 2006)

Very cool.


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## Drew Diller (Jan 4, 2010)

Nicely done!


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## 18bikes (Jan 15, 2007)

to me it looks like you have taken a frame that would already have taken a tapered fork (upper looks like a 44mm, and presumably the lower is too, and a quick google suggests I'm right) with the right headset and made it still fit a tapered fork. Admittedly you've done it very neatly


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## shibiwan (Sep 2, 2012)

18bikes said:


> to me it looks like you have taken a frame that would already have taken a tapered fork (upper looks like a 44mm, and presumably the lower is too, and a quick google suggests I'm right) with the right headset and made it still fit a tapered fork. Admittedly you've done it very neatly


Both of them (upper and lower) measured out to be 41.7mm (yes, its a custom headset from SpecialEd - google Specialized Mindset for more info). If it were 44mm I wold not have needed to go thru all this trouble and gone with an EC44/40 adaptor instead.

I did do a good bit of research before I started modding and that's where I learned about the monstrosity of a headset that Specialized put in their bikes for a while.

As a side note, you can use a campy-style (IS42) headset to replace a Specialized Mindset. The bearings would need to be pressed in, unlike a campy headtube seat where the IS42 just drops right in.

-S
Sent from my Kindle Fire using Tapatalk 2

P.S. here's Spesh's techdoc that mentions their headsets, including the Mindset if anyone's interested in reading more.

Pic of the specialized mindset...


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## adalbertoma (Jul 8, 2018)

shibiwan said:


> Both of them (upper and lower) measured out to be 41.7mm (yes, its a custom headset from SpecialEd - google Specialized Mindset for more info). If it were 44mm I wold not have needed to go thru all this trouble and gone with an EC44/40 adaptor instead.
> 
> I did do a good bit of research before I started modding and that's where I learned about the monstrosity of a headset that Specialized put in their bikes for a while.
> 
> ...


I know this thread is quite old now, and so is my bike ('08 S-Works Carbon HT), but since this was a great work, I decided to reply and ask for advice.

I bought a Fox 34 tapered fork for my bike and am trying to find a way to mod the mindset headset. I had no idea what headset I had when I got the fork (bike noob here, starting to learn some maintenance stuff), so I ended up purchasing a Cane Creek ZS44 for the bottom, but it didn't help as it is 44mm vs the 42mm on my bike. Now I'm thinking of what to do. I thought about enlarging the Spesh headset 1mm in all directions with a Dremel to fit the cup, but I am afraid I might screw it up either with the angles or by making it weaker.

Any suggestions? I don't have the tools or the skills for making an adaptor like you did, so the Dremel is what came first to my mind.

Oh, and BTW, may I ask how did this modification hold up? Do you still have the bike, by any chance?

Thanks a lot!


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## Eric Malcolm (Dec 18, 2011)

DO NOT dremel this out. Serious damage if you do.
Find someone who can machine a bottom cup to fit in the frame and purchase the bearing required. You don't have to do the cosmetic stuff like the OP did. This mod will look a bit like an enlarged egg, but will be functional.

Eric


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## adalbertoma (Jul 8, 2018)

Actually I was not going to Dremel everything out. My intention was to enlarge the upper part of the bottom mindset cup so that the fork could sit correctly (I believe Shibiwan did the same, per his first post) and then enlarge 1mm in every direction very slowly and carefully on the bottom part of the mindset to be able to fit the 44mm Cane Creek cup and bearing (which I already have and wouldn't need to have anyone machine that).

It would be a great option to just take out the mindset cup and replace with another adapter cup machined exactly to my needs, however I have no idea on who to look for. Not sure if my LBS would do that or could recommend someone.


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## Feldybikes (Feb 17, 2004)

Though the work the OP did was very slick, I wouldn’t recommend trying to duplicate it or something like it. You’re better off selling/returning the fork or, given its age, getting a new frame. If you really dig the frame but need a replacement fork, MRP still makes good forks with a straight 1 1/8” steerer.


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## adalbertoma (Jul 8, 2018)

The point is that I already have the Fox fork, which is basically new and I've got no money atm to spend with a new 1 1/8 fork or a new frame. There are other priorities going on in terms of cash, so no way to spend money on this.

I still haven't got the guts to Dremel the cup, but I was wondering if it is possible to remove the mindset cup from the carbon frame without damaging the head tube and maybe add something around the cane creek zs44 to enlarge its OD and replace the mindset cup with the cane creek only.

What do you guys think?

Is the mindset glued to the carbon frame in any way or does it come out easily?


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## NYrr496 (Sep 10, 2008)

Wow. Pretty slick. 
I have an 08 aluminum FS Stumpjumper frame and my son wants it. I actually found him an X Fusion fork with a straight steerer tube and a 15mm thru axle. Pretty nice.


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## adalbertoma (Jul 8, 2018)

*Success!*

Hey, I just wanted to share an update. With the right amount of patience and a Dremel on medium speed plus a tungsten grinding bit, I was able to enlarge the specialized mindset headset out to 44mm and fit the Cane Creek EC44 cup in the bottom headset of my Specialized S-Works Carbon HT frame.

It took me close to 2 hours and a half, but now my bike is fully compatible with tapered forks, with the use of this external cup.

I had to enlarge the inside dent that holds the original bearing in order to press the whole EC44 cup in the bike (I didn't want to saw it, as I believe the cup would make the headset stronger if kept uncut.

If you're on the same boat as myself, and don't have the machinery skills, I would say it can be done with the Dremel if you have enough patience and a little bit of skill with it.

Here are two pictures of how it looks like after done:


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