Threadless Conversion Headset
05-11-18 | 09:32 AM
#1
Thread Starter
Senior Member
Joined: May 2004
Posts: 12,103
Likes: 96
From: Wilmington, DE
Bikes: 2016 Hong Fu FM-079-F, 1984 Trek 660, 2005 Iron Horse Warrior Expert, 2009 Pedal Force CX1, 2016 Islabikes Beinn 20 (son's)
Threadless Conversion Headset
At the risk of further hijacking the retro-roadie thread and/or my own open mold disc road bike build thread, I'm going to start a separate thread to post some details about the threadless conversion headset I designed for my Trek 660:
Product shots below:
First, it is not a standard adapter in any way. You cannot install it without replacing at least the upper headset cup, though I made a new lower cup assembly as well. Mismatched parts just don't cut it!
Second, the way it works is quite simple. Instead of having an upper threaded race that merely adds bearing preload, the upper race of the conversion headset includes a 1 1/8" tube feature. The upper race is bonded to a quill which acts both as an anchor for the tube like a standard quill stem, as a means of locking out the headset adjustment, and completes the remainder of threadless tube. Installation/adjustment is as simple as threading on the upper assembly until desired bearing preload is achieved then using a 6mm hex key to tighten the quill. By using the quill in this manner, the standard locknut on a threaded headset is eliminated, and so is the fairly annoying process of adjusting a threaded headset. Here's a cross section of the CAD file for the upper assembly:
If you look right above the cartridge bearing you can see the internal threads on the upper race that grab the fork's steerer tube (and a dust seal). Above those threads is clearance for extra steerer tube. Of course, there is a limit to just how much extra can be accommodated. The quill is expanded by turning the top cap which has a long steel stud fixed to it (threads and Loctite). The lower threads on the steel stud draw the wedge into the quill's taper causing it to expand. Fully tightened, it won't turn or pull out and the concentric expansion of the quill doesn't disturb the headset's bearings. My original prototypes used a simple top cap and a standard bolt (like a typical threadless adapter) but I hated the look and moved to this updated design:
If you look super close at the above photo you'll notice a very slight difference in the design of the upper race. That's because my Trek still has one of the original prototypes on it, minus the old-style top cap. I have also cut my conversion down to almost the minimum such that the top cap is flush with the top of my stem with no spacers underneath. I did think about more than myself when creating this and designed spacers with an internal o-ring to keep them from rattling and complete the threadless conversion look for those who don't want to run their stems so low. The o-rings were necessary because this design doesn't put any preload force on the spacers (meaning you can swap them around without messing with headset preload, too).
Any further questions?
Product shots below:
First, it is not a standard adapter in any way. You cannot install it without replacing at least the upper headset cup, though I made a new lower cup assembly as well. Mismatched parts just don't cut it!
Second, the way it works is quite simple. Instead of having an upper threaded race that merely adds bearing preload, the upper race of the conversion headset includes a 1 1/8" tube feature. The upper race is bonded to a quill which acts both as an anchor for the tube like a standard quill stem, as a means of locking out the headset adjustment, and completes the remainder of threadless tube. Installation/adjustment is as simple as threading on the upper assembly until desired bearing preload is achieved then using a 6mm hex key to tighten the quill. By using the quill in this manner, the standard locknut on a threaded headset is eliminated, and so is the fairly annoying process of adjusting a threaded headset. Here's a cross section of the CAD file for the upper assembly:
If you look right above the cartridge bearing you can see the internal threads on the upper race that grab the fork's steerer tube (and a dust seal). Above those threads is clearance for extra steerer tube. Of course, there is a limit to just how much extra can be accommodated. The quill is expanded by turning the top cap which has a long steel stud fixed to it (threads and Loctite). The lower threads on the steel stud draw the wedge into the quill's taper causing it to expand. Fully tightened, it won't turn or pull out and the concentric expansion of the quill doesn't disturb the headset's bearings. My original prototypes used a simple top cap and a standard bolt (like a typical threadless adapter) but I hated the look and moved to this updated design:
If you look super close at the above photo you'll notice a very slight difference in the design of the upper race. That's because my Trek still has one of the original prototypes on it, minus the old-style top cap. I have also cut my conversion down to almost the minimum such that the top cap is flush with the top of my stem with no spacers underneath. I did think about more than myself when creating this and designed spacers with an internal o-ring to keep them from rattling and complete the threadless conversion look for those who don't want to run their stems so low. The o-rings were necessary because this design doesn't put any preload force on the spacers (meaning you can swap them around without messing with headset preload, too).
Any further questions?
Last edited by joejack951; 05-14-18 at 05:06 PM.
05-11-18 | 09:40 AM
#2
Thread Starter
Senior Member
Joined: May 2004
Posts: 12,103
Likes: 96
From: Wilmington, DE
Bikes: 2016 Hong Fu FM-079-F, 1984 Trek 660, 2005 Iron Horse Warrior Expert, 2009 Pedal Force CX1, 2016 Islabikes Beinn 20 (son's)
Basic specs:
Converts ISO 1"-24 threaded to 1 1/8" threadless (dia. 30.2mm cups, dia. 26.4mm crown race)
Sealed steel cartridge bearings with Buna-N dust seals, top and bottom
Uncut weight: 265 grams
Uncut threadless steerer tube length: 90mm
Minimum cut length: 38mm (includes 2.5mm for top cap)
Lower stack height: 12.5mm
Upper stack height: 14.6mm
Steerer tube requirements:
1. Must be 27mm min/45mm max longer than bare headtube measured from fork crown
2. Threads on steerer tube must end no more than 16mm above the edge of the bare headtube (using fork crown as reference)
Installation video:
Converts ISO 1"-24 threaded to 1 1/8" threadless (dia. 30.2mm cups, dia. 26.4mm crown race)
Sealed steel cartridge bearings with Buna-N dust seals, top and bottom
Uncut weight: 265 grams
Uncut threadless steerer tube length: 90mm
Minimum cut length: 38mm (includes 2.5mm for top cap)
Lower stack height: 12.5mm
Upper stack height: 14.6mm
Steerer tube requirements:
1. Must be 27mm min/45mm max longer than bare headtube measured from fork crown
2. Threads on steerer tube must end no more than 16mm above the edge of the bare headtube (using fork crown as reference)
Installation video:
Last edited by joejack951; 06-20-20 at 05:20 PM. Reason: Added steerer tube requirements and install video
05-14-18 | 07:37 AM
#4
Port
Joined: Jan 2008
Posts: 9,145
Likes: 6,067
From: Boston
Bikes: 2022 Soma Fog Cutter, 2021 Calfee Draqonfly 44, 1984 Peter Mooney, 2017 Soma Stanyan, 1990 Fuji Ace, 1990 Bridgestone RB-1, 1995 Independent Fabrications Track, 2003 Calfee Dragonfly Pro
Is this available for sale?
__________________
https://rowdml.tripod.com/panmass
https://rowdml.tripod.com/panmass
05-14-18 | 07:46 AM
#5
Senior Member
Joined: Jul 2008
Posts: 3,288
Likes: 4,243
From: The Le Grande HQ
Bikes: Gängl, Trek 938, Raleigh Professional, Paramount, Allez, Guerciotti, Specialized Stumpjumper, Trek 750, Miyata 1000 < Huffy
Super cool, and a creative way around this challenge of using threadless cockpits with older bikes. Yes, yes, more details please! For sale? Some old prototypes laying around that need testing********** 
05-14-18 | 09:02 AM
#6
feros ferio
Joined: Jul 2000
Posts: 22,397
Likes: 1,864
From: www.ci.encinitas.ca.us
Bikes: 1959 Capo Modell Campagnolo; 1960 Capo Sieger (2); 1962 Carlton Franco Suisse; 1970 Peugeot UO-8; 1982 Bianchi Campione d'Italia; 1988 Schwinn Project KOM-10;
Sorry if this sounds snarky, but I still can't get excited about threadless headsets, because of the loss of handlebar height adjustment.
__________________
"Far and away the best prize that life offers is the chance to work hard at work worth doing." --Theodore Roosevelt
Capo: 1959 Modell Campagnolo, S/N 40324; 1960 Sieger (2), S/N 42624, 42597
Carlton: 1962 Franco Suisse, S/N K7911
Peugeot: 1970 UO-8, S/N 0010468
Bianchi: 1982 Campione d'Italia, S/N 1.M9914
Schwinn: 1988 Project KOM-10, S/N F804069
"Far and away the best prize that life offers is the chance to work hard at work worth doing." --Theodore Roosevelt
Capo: 1959 Modell Campagnolo, S/N 40324; 1960 Sieger (2), S/N 42624, 42597
Carlton: 1962 Franco Suisse, S/N K7911
Peugeot: 1970 UO-8, S/N 0010468
Bianchi: 1982 Campione d'Italia, S/N 1.M9914
Schwinn: 1988 Project KOM-10, S/N F804069
05-14-18 | 07:21 PM
#9
Senior Member
Joined: Aug 2017
Posts: 2,773
Likes: 720
From: Central Io-way
Bikes: LeMond Zurich, Giant Talon 29er
I saw an earlier thread where you demo'ed this, pretty snazzy! So you mention spacers, what is the maximum height you could have with spacers, or will there be different lengths.
Either way please send the CNC programs so I can make this out of titanium - or even better the cam files
Either way please send the CNC programs so I can make this out of titanium - or even better the cam files
05-14-18 | 07:25 PM
#10
Thread Starter
Senior Member
Joined: May 2004
Posts: 12,103
Likes: 96
From: Wilmington, DE
Bikes: 2016 Hong Fu FM-079-F, 1984 Trek 660, 2005 Iron Horse Warrior Expert, 2009 Pedal Force CX1, 2016 Islabikes Beinn 20 (son's)
Yes, it is for sale, sorta. I have a tentative plan to market it solely through Amazon but still toying with the idea of a real website. As a result of my indecisiveness and a few other factors, I don't have any online store from which it can be purchased. But that doesn't change the fact that I have production headsets available and am willing to sell them to anyone who will pony up $90 (intro price, includes a set of spacers). PM me for additional purchasing details.
05-14-18 | 07:31 PM
#11
Thread Starter
Senior Member
Joined: May 2004
Posts: 12,103
Likes: 96
From: Wilmington, DE
Bikes: 2016 Hong Fu FM-079-F, 1984 Trek 660, 2005 Iron Horse Warrior Expert, 2009 Pedal Force CX1, 2016 Islabikes Beinn 20 (son's)
What other specifics do you want to know? I'm out of the prototype phase. Sorry!
05-14-18 | 07:42 PM
#12
Thread Starter
Senior Member
Joined: May 2004
Posts: 12,103
Likes: 96
From: Wilmington, DE
Bikes: 2016 Hong Fu FM-079-F, 1984 Trek 660, 2005 Iron Horse Warrior Expert, 2009 Pedal Force CX1, 2016 Islabikes Beinn 20 (son's)
1. Flip the stem. With a -17° stem like mine, I can raise the handlebars significantly by just flipping it over. It won't look as slick but for a long slow ride or to let a friend use for a weekend, it would do the trick.
2. Don't cut the quill all the way. If you are ok with some protruding quill above the stem when the handlebars are fully lowered, you can use the extra height to raise the bars when desired. Combined with a stem flip you could really raise the bars quite a bit, likely far more than a traditional quill would allow. Just make sure your cables are long enough for it.
3. Use an adjustable stem. Last on a list for a reason but you could swap one in for a fixed stem as desired with little fuss if you didn't want to run one all the time.
In all cases, you don't need to worry about headset adjustments like you would with true threadless which makes it less painless, just not as pain-free as a normal quill.
05-14-18 | 07:54 PM
#13
Thread Starter
Senior Member
Joined: May 2004
Posts: 12,103
Likes: 96
From: Wilmington, DE
Bikes: 2016 Hong Fu FM-079-F, 1984 Trek 660, 2005 Iron Horse Warrior Expert, 2009 Pedal Force CX1, 2016 Islabikes Beinn 20 (son's)
My sister's bike received an early prototype, too, and I only partially cut the quill for that install using a few spacers under the stem:
05-15-18 | 06:40 PM
#14
Cyclist
Joined: Jan 2012
Posts: 580
Likes: 27
From: Victoria bc
Bikes: '84 Univega Specialissima, Rawland Stag, '87 Rocky Mountain Blizzard
Absolutely gorgeous! Well done. I'm very disappointed my regular conversion stem has been working well lately. I need more reasons to buy this! Though, really, the way it looks is enough
05-15-18 | 08:34 PM
#15
Senior Member
Joined: Jul 2008
Posts: 3,288
Likes: 4,243
From: The Le Grande HQ
Bikes: Gängl, Trek 938, Raleigh Professional, Paramount, Allez, Guerciotti, Specialized Stumpjumper, Trek 750, Miyata 1000 < Huffy
Beautiful piece of kit. The main questions were price and availability. I think you answered those in response to another poster.
Great work!
05-18-18 | 09:15 AM
#16
Thread Starter
Senior Member
Joined: May 2004
Posts: 12,103
Likes: 96
From: Wilmington, DE
Bikes: 2016 Hong Fu FM-079-F, 1984 Trek 660, 2005 Iron Horse Warrior Expert, 2009 Pedal Force CX1, 2016 Islabikes Beinn 20 (son's)
This threadless conversion headset yields some added stiffness as a result of using the upper race to support the quill. The upper race is supported at a far larger radial distance (by the headset bearings) than a quill on the ID of the steerer tube (15mm vs. 11.1mm). Having used a bike with a back to back comparison of threadless adapter to threadless conversion headset it really is a noticeable difference. You can actually take advantage of the extra stiffness of a threadless stem and modern handlebars now.
There is also a smidgen of weight savings vs. an aluminum threaded headset and threadless adapter combo, a number which increases when you cut down the quill. I've toyed with idea of titanium hardware and ceramic bearings for even greater weight savings but haven't yet gone there.
05-18-18 | 02:54 PM
#17
Senior Member
Joined: Jul 2008
Posts: 3,288
Likes: 4,243
From: The Le Grande HQ
Bikes: Gängl, Trek 938, Raleigh Professional, Paramount, Allez, Guerciotti, Specialized Stumpjumper, Trek 750, Miyata 1000 < Huffy
Okay! After reading through this again, I do have some additional questions -
1. I'm assuming the cartridge bearings are replaceable - where can one find drop-in replacements?
2. Are you seeing any additional wear, especially on the top bearing, from having the torque/load of the downward force on the handlebars and stem transfer to the bearing? The way my brain is processing it...on a normal quill stem, the load from body weight follows this path: handlebars --> stem --> steerer (usually steel) --> headset. On your design, it is handlebars --> stem ---> upper headset cap. Just curious. I can see how it can be immensely more stable and stiff, but my brain keeps thinking about that 'push down' force directly against the top headset cap.
3. Is the bolt steel, and the wedge aluminum?
4. Any info on country of origin?
Thanks!
1. I'm assuming the cartridge bearings are replaceable - where can one find drop-in replacements?
2. Are you seeing any additional wear, especially on the top bearing, from having the torque/load of the downward force on the handlebars and stem transfer to the bearing? The way my brain is processing it...on a normal quill stem, the load from body weight follows this path: handlebars --> stem --> steerer (usually steel) --> headset. On your design, it is handlebars --> stem ---> upper headset cap. Just curious. I can see how it can be immensely more stable and stiff, but my brain keeps thinking about that 'push down' force directly against the top headset cap.
3. Is the bolt steel, and the wedge aluminum?
4. Any info on country of origin?
Thanks!
Last edited by AdventureManCO; 05-18-18 at 02:58 PM.
05-18-18 | 04:25 PM
#18
Senior Member
Joined: Oct 2013
Posts: 3,454
Likes: 909
From: Connecticut
Bikes: are fun!
Very, very cool. Nice work! Looks way better than the usual quill -> 1-1/8” adaptors and nice to have a bit of added front end stiffness. Your Trek looks like a blast. I could see using one in silver on a build that’s been bouncing around in my mind for a while. I’ll have to keep an eye out, glad you started a separate thread otherwise I would have probably missed this.
05-19-18 | 01:20 AM
#19
Master Parts Rearranger
Joined: Mar 2015
Posts: 4,840
Likes: 2,782
From: Portlandia's Kuiper Belt, OR
Bikes: 1987 Woodrup Competition - 2025 Trek Checkpoint SL 6 Gen 3 - 1987 Lotus Legend - 2024 Trek Emonda ALR Rim Brake - 1980 Trek 510 - 1988 Cannondale SR500 - 1985 Trek 670 - 1982 Trek 730
Thanks to a Marinoni that I picked up a few months ago, I now have a different quill stem adapter setup that allows me to make it look as seamless as possible. It has a -17° rise for that extra slammed cool-guy look. 
And all I had to do was add a beer can shim to get it to work properly (it worked mostly upon initial assembly)!
Bike is the recently acquired '87 Prologue, now with a 7900 FD (pictured is a 7410 FD) that shifts perfectly and doesn't chuck chains over chain rings (compatibility is an amazing thing!). I will echo the sentiment--as I have for a long while now--that doing a stem conversion gives an immediate "sure" feeling up front. Solid, yet never harsh. Love the look, too. Also: typically lighter. I dropped 160g(!) out of my front end with this conversion, bringing the total ready-to-ride weight down to 20 lb 5.5 oz.
And all I had to do was add a beer can shim to get it to work properly (it worked mostly upon initial assembly)! Bike is the recently acquired '87 Prologue, now with a 7900 FD (pictured is a 7410 FD) that shifts perfectly and doesn't chuck chains over chain rings (compatibility is an amazing thing!). I will echo the sentiment--as I have for a long while now--that doing a stem conversion gives an immediate "sure" feeling up front. Solid, yet never harsh. Love the look, too. Also: typically lighter. I dropped 160g(!) out of my front end with this conversion, bringing the total ready-to-ride weight down to 20 lb 5.5 oz.
05-19-18 | 09:09 PM
#21
Thread Starter
Senior Member
Joined: May 2004
Posts: 12,103
Likes: 96
From: Wilmington, DE
Bikes: 2016 Hong Fu FM-079-F, 1984 Trek 660, 2005 Iron Horse Warrior Expert, 2009 Pedal Force CX1, 2016 Islabikes Beinn 20 (son's)
Okay! After reading through this again, I do have some additional questions -
1. I'm assuming the cartridge bearings are replaceable - where can one find drop-in replacements?
2. Are you seeing any additional wear, especially on the top bearing, from having the torque/load of the downward force on the handlebars and stem transfer to the bearing? The way my brain is processing it...on a normal quill stem, the load from body weight follows this path: handlebars --> stem --> steerer (usually steel) --> headset. On your design, it is handlebars --> stem ---> upper headset cap. Just curious. I can see how it can be immensely more stable and stiff, but my brain keeps thinking about that 'push down' force directly against the top headset cap.
3. Is the bolt steel, and the wedge aluminum?
4. Any info on country of origin?
Thanks!
1. I'm assuming the cartridge bearings are replaceable - where can one find drop-in replacements?
2. Are you seeing any additional wear, especially on the top bearing, from having the torque/load of the downward force on the handlebars and stem transfer to the bearing? The way my brain is processing it...on a normal quill stem, the load from body weight follows this path: handlebars --> stem --> steerer (usually steel) --> headset. On your design, it is handlebars --> stem ---> upper headset cap. Just curious. I can see how it can be immensely more stable and stiff, but my brain keeps thinking about that 'push down' force directly against the top headset cap.
3. Is the bolt steel, and the wedge aluminum?
4. Any info on country of origin?
Thanks!
2. On my design, the load from the stem is shared between the upper bearing and the steerer. Remember that there is still a quill going down inside the steerer tube just like a typical threaded headset and stem. 'Real' threadless headsets do load the upper bearing just like you describe, though, and those don't seem to be grinding through upper bearings so I don't expect to, and have not seen for the record, any unusual upper bearing wear.
3. Bolt and wedge are both steel with black zinc plating. Not worth risking safety for some weight savings here. Nearly everything else is anodized 6061-T6 aluminum save for the dust seals (Buna-N), top cap plug (not shown, EPDM), top cap washer (304 SS), and bearings (52100 steel with Buna-N seals).
4. Parts are sourced from a variety of trusted vendors in China. Assembled in USA.
05-19-18 | 09:12 PM
#22
Thread Starter
Senior Member
Joined: May 2004
Posts: 12,103
Likes: 96
From: Wilmington, DE
Bikes: 2016 Hong Fu FM-079-F, 1984 Trek 660, 2005 Iron Horse Warrior Expert, 2009 Pedal Force CX1, 2016 Islabikes Beinn 20 (son's)
Thanks to a Marinoni that I picked up a few months ago, I now have a different quill stem adapter setup that allows me to make it look as seamless as possible. It has a -17° rise for that extra slammed cool-guy look. And all I had to do was add a beer can shim to get it to work properly (it worked mostly upon initial assembly)!
Bike is the recently acquired '87 Prologue, now with a 7900 FD (pictured is a 7410 FD) that shifts perfectly and doesn't chuck chains over chain rings (compatibility is an amazing thing!). I will echo the sentiment--as I have for a long while now--that doing a stem conversion gives an immediate "sure" feeling up front. Solid, yet never harsh. Love the look, too. Also: typically lighter. I dropped 160g(!) out of my front end with this conversion, bringing the total ready-to-ride weight down to 20 lb 5.5 oz.
And all I had to do was add a beer can shim to get it to work properly (it worked mostly upon initial assembly)! Bike is the recently acquired '87 Prologue, now with a 7900 FD (pictured is a 7410 FD) that shifts perfectly and doesn't chuck chains over chain rings (compatibility is an amazing thing!). I will echo the sentiment--as I have for a long while now--that doing a stem conversion gives an immediate "sure" feeling up front. Solid, yet never harsh. Love the look, too. Also: typically lighter. I dropped 160g(!) out of my front end with this conversion, bringing the total ready-to-ride weight down to 20 lb 5.5 oz.
05-19-18 | 09:14 PM
#23
Thread Starter
Senior Member
Joined: May 2004
Posts: 12,103
Likes: 96
From: Wilmington, DE
Bikes: 2016 Hong Fu FM-079-F, 1984 Trek 660, 2005 Iron Horse Warrior Expert, 2009 Pedal Force CX1, 2016 Islabikes Beinn 20 (son's)
Very, very cool. Nice work! Looks way better than the usual quill -> 1-1/8” adaptors and nice to have a bit of added front end stiffness. Your Trek looks like a blast. I could see using one in silver on a build that’s been bouncing around in my mind for a while. I’ll have to keep an eye out, glad you started a separate thread otherwise I would have probably missed this.
05-19-18 | 10:27 PM
#24
Master Parts Rearranger
Joined: Mar 2015
Posts: 4,840
Likes: 2,782
From: Portlandia's Kuiper Belt, OR
Bikes: 1987 Woodrup Competition - 2025 Trek Checkpoint SL 6 Gen 3 - 1987 Lotus Legend - 2024 Trek Emonda ALR Rim Brake - 1980 Trek 510 - 1988 Cannondale SR500 - 1985 Trek 670 - 1982 Trek 730
To clarify on the beer can shim: There is a 1" quill stem adapter with fine splines. A spacer/shim (with a full length slit) slots over the adapter. The 1 1/8" stem slides over the spacer/shim and clamps down as normal. All of it is super straight forward, however, the spacer/shim+adapter diameter ended up being a touch too small for this stem's clamp. The stem could have been made "too big" with regard to tolerances, but whatever, there I was needing a solution. Just needed a touch more diameter. I cut up a section of a 12 oz. can of Bale Breaker's Bottom Cutter Imperial IPA (pour it into a glass to properly taste it, if you ever get the chance
) and used it to shim the adapter. It added not even a gram of weight while solving the problem. I am a happy camper. For fun, the Modolo quill stem weighed a whopping 359g. No wonder I could knock 160g total out of the "old" stem/bar combo.
05-24-18 | 01:54 AM
#25
Senior Member
Joined: Dec 2009
Posts: 9,563
Likes: 735
From: Melbourne, Oz
Bikes: https://weightweenies.starbike.com/forum/viewtopic.php?f=10&t=152015&p=1404231
Holy crap, this unit is slick AF. I think I've daydreamed about something very similar, but you made it happen.
Mad props.
Mad props.