thook

of course

i'm not suggesting a threadless stem, though. just the headset along with a threaded adjusting ring and locknut and doing away with the star fangle insert business. in essence, it would work much like the modern headset adapter designed to be able to use a quill stem on a threadless steerer set up

J.Higgins 

I just went through this with my Bilenky last year, and now that you've jogged my memory, it was 1" threadless STEMS that I had trouble sourcing. To get the proper stem length and angle, I had to upsize to a 1-1/8 size, and use shims. It irritated me that I just couldn't find one. So I guess I can say my bad, conflicting memory. I only got two brain cells left, and those are arcing to ground.

unworthy1

Interesting idea, not sure if it would work in reality but "in theory" it could (and as Johnny Cash reminds us: "EVERYTHING works in Theory") But you need to find the donor 1" threadless headset to cannibalize the top cup/race from. I actually may have such a thing but would need to scrounge to maybe find such, and probably would be black (not silver).

I will amplify that using the conventional threadless HS and stem is NOT recommended on a threaded steerer (even if the length works, which with just 50mm of steerer to work with the OP's is not even possible, the stems are almost all 50mm clamp height alone, so your HS stack would have to be "zero"). Not just cause the threading weakens the steerer where the stem applies clamping pressure, BUT, more important, is that the star-fangled nut has to be pressed inside that steerer and often will be applying internal pressure in the same weakened section of steerer: so too risky!

Jordanmilo

The only advantage I can see to anything threadless is being able to remove the front of the stem, thus making handlebar work and/or changes easier. Then again, my knowledge of bicycle tech froze somewhere around 1981.

thook

lol...i know the feeling. synchronizers don't always mesh

the stems are harder to find, for sure. with some patience, they do turn up on ebay. but, like you said, angles and lengths...it can be troublesome. it's not the most glamorous of stems, but i got lucky enough and found an UNO silver 1" at 90mm reach, 15* rise, and 25.4 clamp....which will work on 26mm bars, if you aren't too picky. it's a 2 bolt faceplate. i'd give it an 8 out of 10 on aesthetics...and i'm kinda picky on that part

Road Fan

I'm late to this thread, but I have some thoughts to share. The 50 mm stack is odd as is the 1" thread length, and it looks like you do not have an example of what headset previously fit the Paco frame to use as a model of what it needs. If your measurement of 50 mm is accurate, then yes, you cannot make a headset work which has a taller stack than 50 mm, without omitting the spacer.

It will also be hard to find a headset that tall, so adding spacers between the threaded cup and the top lock nut is attractive. But this is where the 1" (25 mm) thread length could be a problem. I just measured the thread length of two of my headsets. For a Stronglight Delta, it is about 15 mm. For a Tange Technoglide with sealed angular contact bearings, it is 16 mm. As they sit there is no problem, but both of these are have stacks between 37 mm and 40 mm. To reach up far enough a 10 mm spacer is needed, and then 25 mm will be on the edge and might not work. I don't think these headsets are unusual designs, and I think the fork threads might not fully engage both the threads of the threaded upper cup and the locknut, with the spacer added.

Is the fork that is paired with the Paco frame the correct fork? It seems to make some difficulties that are rather unusual. Rethreading it might work, and possibly a different fork should be found.

Jordanmilo

I don't know if that's the original fork; with a bike that old and rare I'd have no way to find out. But the fork is marked "Paco" and there's not a lot of those frames out there.

I just returned from a local bike shop. They ordered a Orange-Velo sealed bearing headset (which was my preference) and think all that's needed is about 10mm of spacer for the whole thing to work. We shall see!

thook

not all threadless stems have a removable face plate. particularly older/vintage cromo stems (eg. salsa) in the 1" steerer size. i have an 80mm (length) salsa threadless cromo stem. looks great on classic lugged bikes from late 80's early 90's




just to reiterate, the only "advantage" i'm trying to point out here for you is the ability to still use your current fork in lieu of getting the steerer further threaded. and, of course, if absolutely nothing else....no other approach/parts... will work. and, like i said, with what i'm suggesting, you can still absolutely use a quill stem. and, if you smooth the threads on the threaded top bearing race of a threaded headset using it "functionally" as a threadless headset, it will still look like a threaded set. no one but you or us () will be the wiser. sorry if it seems i'm trying to pound the idea across, but to me it really seems like one of if not the easiest/cheapest solution to your dilemma. and, i'm 99.9% sure it will work quite well

thook

i'm confident it would work. and, you wouldn't need to cannibalize a threadless headset. a threaded one, yes, if the threadless set is used. but, he should already have the two/three necessary parts; spacer/s, adjusting ring, top nut. anyway, there's no difference between a threadless headset bearings/cups/races and a threaded one. the only difference is the way it secures/tightens everything up. so, either use the entire threadless set, or use the original threaded set and shave out the threads in the top cup/race. i suppose the only potential place to mess up is the need to cut off the right amount of threaded section so that the top lock nut has the right amount threads to tighten down as far as it in needs to....ie. not having too much or too little. measurements would be in order....and not a difficult thing

i will say i've used a cromo threadless stem on a threaded steerer section. granted, i didn't run it that way real long nor did i subject it to harsher conditions, but it certainly worked and it didn't fail. it was just fugly because of the aged and differing colored paint/s. at any rate, this is the circumstance where i'd de-threaded a campy headset that i've mentioned above.....and the source for the idea i seem to be unnecessarily (ridiculously?) redundant about here....lol. it seems he's already made up his mind on the fix

Jordanmilo

OK, thook, I get you now. The LBS I went to this morning thinks they can make this work without anything rad, though.

unworthy1

Maybe I was not following, but seems to me the problem this addresses is that (leave the bottom stack out, it can remain as-is with whatever you have that fits fork and headtube) your TOP stack needs either the top race or cup that fits this headtube but then the issue is you cannot screw down any top THREADED cup (or race) because of the threading which does not extend far enough on the steerer. Even tho your top nut (with spacers or not) would contact the top race/cup it's not gonna work, the top bearing is not "in-play" and entire HS will not be tightened. So that where if you swap in the THREADLESS HS components that mate-up (fit the headtube, work together) then top race-or-cup from a THREADLESS unit slides right down on the steerer cause it doesn't need threads). Then the THREADED top nut (with a washer and spacers as needed or top of steerer gets cut so top-nut has just the threads required) tightens it all down and... "bob's your uncle". At least this sound plausible to me as I picture it but never having tried it I can't say 100% certain there would be not any unexpected problem.

EDIT: giving this a second read I think we are both saying about the same thing but coming at it from 2 different assumptions: either using a threadless HS and adding a threaded top nut or using a threaded HS and swapping in the "top stack" from a threadless...it amounts to the same thing. Looking at the one pic that shows the exposed steerer above the head tube I don't know if this "working steerer" is actually 50mm with 25mm of threading, either there's a longer unthreaded section than 25mm or the steerer is shoved up high in the headtube and that pic is misleading. ANYhow, if you can get the bottom and top stacks of "whatever HS" to add up to "the length of steerer above the head tube with maybe 10mm of threading" then you typically only need about that much for the threaded top cup and top nut to both screw down tight. So you just add the hated spacers or cut off threaded steerer to fit. If no way to get that much threading then you want the stacks to add up to the "section of smooth steerer" use UNTHREADED top cup/race and leave enough threading for a washer and top nut (let's say 3-4mm) and trim to fit. Guessing that the LBS involved has all this figured out and the spec sheets for all the potential HS (that list stack height for top and bottom sections). Measure thrice and cut once!

thook

yes...more than less we're saying the same thing. there's only one thing about you're last paragraph i'd differ on as i'm not suggesting the same arrangement, but it doesn't matter. frankly...i'm a little exhausted at typing about it....lol. if i had a way to take pictures, i could assemble such a set up as i have all the parts to do so and just illustrate it that way.

martl

most bike shops today think Campagnolo is a clothing brand.

Road Fan

I agree it's hard to talk about this question without good pictures, and to be sure what we all are suggesting makes any sense, if we don't really get the situation.

The thread length on two headsets I measured is 15 and 16 mm, so the threaded section of the steerer is long enough if the headtube is not too long. The threaded cup will by necessity be close to the top of the head tube. It needs about 7 or 8 mm for thread engagement. The top nut also needs 7 or 8 mm of thread, but that of necessity is at the top of the steer tube. With 50 mm of free head tube and about 14 mm of lower bearing stack up, there is then 36 mm free above the top of the head tube. For a headset with a 40 mm total stack, this needs to more like 26 mm. So between the top nut and the top of the threaded cup, there will be a 10 mm gap. Normally such gaps are filled by spacers, such as a 5 mm front brake cable hanger and a 5 mm stem bell mounting ring, or a stack of generic spacers. Same could go for a 36 or 35 mm headset like the old Tange Levin. So a conventional threaded headset can be used, but about 10 mm of spacers are needed. If the bottom stack is less than about 14 (I think I've seen 12 on my Stronglights), then probably the thread needs to be lengthened by a few millimeters. I've heard the problem with that is to make sure the new thread seamlessly mates with the original thread.

If new thread can be cut seamlessly, and a lower-profile headset is the goal, you could trim the head tube and extend the threading, if a better-matched fork is not available.

Road Fan

Aren't there Campy socks? I certainly haven't found Campy blue jeans. There are Campy cycling caps. I'm waiting for the tux to come out.

martl

There was a brand of sports clothing goods called "Campagnola" around a few years back. Doubt it ever made it across the pond over to you guys.