tiger1964 

I figured easy to measure, the frame and fork are sitting there on two wheels, there's no headset installed so the bottom of the head tube is resting on the fork crown. The amount of steering tube sticking up from the head tube is only 35mm.

I was considering Velo Orange's French headset but the stack height is 41mm, so I suspect no-go. I have the bike's original headset, in decent shape but the cups are not even plated, a cheapie (I recall from my youth the Stronglight #s of P3 & V4, are those valid?). So what is commercially available that fits?

Chombi1 

IIRC, the shortest stack height I have dealt with yet is something like 38mm. 35mm sounds awfully short. I'm wondering whether one of those headsets without a top locknut was installed on that bike. Stronglight and JPR made headsets that had a Delrin ring in the top race piece that acts like the nylon bushing at the tip of locknut, eliminating the need for a top locknut. That may result in being able to have a shorter steerer tube the usual.....

Ghrumpy

Yes. The Stronglight P3 has a stack height of 34mm. A front brake cable stop will add a couple mm. There's also a P3 copy made by Lightrace, often seen on bike-boom Peugeots. That might be what you have.

The V4 has more stack, around 39-40mm.

El Chaba

The Lightrace headset has a stack height of 34mm, too.....Allow another 2-3 mm for a centerpull cable hanger if needed....

lostarchitect 

Tange Passage is my go-to when stack height is an issue (it's something like 30.x mm), but I don't think I have ever seen a French threaded one. Couldn't hurt to look around, though.

gaucho777 

I don't know how particular you are in terms of style/era. That said, the Shimano 105 headset has a very low stack height of 33.5mm. Here's an ebay seller with several French-threaded units:

https://www.ebay.com/itm/vintage-NOS...4AAOSwLF1X9ooh

VeloBase.com - Component: Shimano HP-1055, 105SC

You might even need a spacer!

thumpism 

If you need a centerpull hanger and the 3mm of space for it is crucial, you can get a hanger that clamps to the stem's quill. Or use sidepulls.

tiger1964 

Thanks for input!

The headset I have I have looks to be in decent condition, just not pretty. As I am taking a bunch of other small parts to the chrome shop anyway, I possibly could get the non-chromed races chromed. I'll keep an eye out for these. I guess I could deal with a Tange or Shimano headset, both not made in France, but I think the black finish would be a deal-killer.

Still using the stem I had on the bike as a teenager in the mid-70's, a Pivo (yeah I know) drilled to pass the cable and act as a stop. I presume when I got the bike, as a frame and bag o' parts, it had a hanger. Once.

unworthy1

don't chrome-plate the working surfaces of races or cups, it will wear off and muck up bearings.

fietsbob

An overhaul & new balls after the chrome wears through , takes care of that..

Low Cost, headsets may not bother with grinding /polishing the races after plating ..

tiger1964 

+1, will have a discussion with the plater, maybe there's nothing to be done about plating the races but other headsets come plated...

Salamandrine 

FYI. Masking is done all the time when chrome plating. All the plater needs to do is brush over the ground races with a liquid masking material.

TallRider

I realize I'm almost 2 years later here, but I wanted to express my annoyance that the V.O. French headset has 41mm stack height. Lots of older bikes have low-stack headsets (I have a Centurion Ironman with 33.2mm diff between steerer and headtube, and a mid/late-70s Peugeot with 35.5mm).
I appreciate that they are making/sourcing a French headset, but odd that they went with a design that simply won't work on a lot of the bikes that would want a new French headset.

bikemig 

Agreed. I'm rehabbing a 1970s Mercier 300 and the headset is shot. I measured the stack height and it's right around 34 mm which is crummy. I have a french threaded stronglight A9 I was hoping to use as a replacement but it has a 38 mm stackheight.

So looks like I'll be shopping around for an old headset.

There's a great post here by verktyg on stack height for French headsets. gitaneusa.com :: View topic - Headset stack height

The crown race can be an issue too. Looks like I'll be spending some time on eBay France looking for a headset (after I measure the crown race), lol.

JohnDThompson 

Usually, the crown race and lower pressed cup are what wears out on headsets; the upper pressed cup and threaded race don't carry load (they just provide alignment) and so don't really wear. You can often just replace the crown race and lower pressed cup with any ISO headset parts of similar stack (e.g. Tange Levin, etc.) and keep the current upper race and threaded parts.

bikemig 

Thanks! Yeah that's what I was thinking as well. I need to take it apart and see what is going on. I've never seen a headset binding quite as much as this though so I may need the uppers as well.

I have a Stronglight P3 competition headset english threaded on another bike. If the crown race is the same, I might just swap out the cups and crown race from the english threaded P3 and keep the original threaded bit from the Mercier. The inside diameters are close (26.4 for ISO, 26.5 French if I'm lucky 27 if I'm not) (if I'm reading the Sheldon Brown crib sheet right):

https://www.sheldonbrown.com/cribsheet-headsets.html

unworthy1

If it's a FR fork (and not a Tange replacement) I'd bet money you would not encounter a 27.0 crown race, as that's JIS standard. I like JDT's suggestion but you also need to confirm the crown race physically fits the OEM cup if you keep that cup, sometimes the diameter is a tiny bit too big (NG) or too small (just makes a wide gap that's asking for grit to invade. If you swap both the race and lower cup then just confirm the cup fits the headtube: Tange HSs usually have matched cup with the race so you get the 30.2mm cup with a 26.4 race HS (what you'd want to try for most FR applications) and the 30.0 cup with a 27.0 race HS

rustystrings61 

My Allegro was apparently originally the “C” grade variant that left the factory with a Stronglight P3. A previous owner recut the crown for 26.4. I have been very pleased with the basic Tange lower assembly mated with the upper parts of a generic steel headset that was original issue on a lesser Motobecane. If memory serves, Chas./verktyg has said Motobecane’s budget low-stack headsets were actually made as O.E.M. units by Stronglight.

tiger1964 

I had had any sense, when I took the frame to a frame builder to have some braze-ons added, I could have asked for a new, longer steerer tube.

CMAW 

Campagnolo Gran Sport (and Pista) headsets have a 34mm stack height and were available in 25x100. There's one for sale on French ebay right now.

tiger1964 

Been checking out eBay looking for any of these options mentioned for a while now, unobtanium unless I want to spend $350+ on a used headset.

bikemig 

Post 18 gives you a cheaper solution. See if you can find the top to the French threaded P3 (the cup, the locknut etc) as those tend to survive. The problem is nearly always the bottom. So find a low stack height headset and use the bottom. The crown race will be 26.4, not 26.5, but posters here have made that work.

Here is some useful tech info:

https://velo-orange.com/pages/threaded-headset-basics

https://www.sheldonbrown.com/cribsheet-headsets.html

rustystrings61 

And it bears repeating - the generic steel headsets Motobecane used were allegedly built by Stronglight and are low stack height. The top half I have has been working beautifully with a Tange lower unit; perhaps I should fish out the lower half and see if someone needs it.

awac

Ha! Four years on, and I have found this because I have exactly the same measurement, well 34.4mm! You would think someone would be making them by now! LOL. Well my search goes on!

El Chaba

Cycles Grand Bois has a reproduction headset of a vey high quality that matches the appearance of a Stronglight P3 or a Lightrace. It has some alloy parts in the mix as well as steel and includes a ball set in retainers. It has an advertised stack height of 35 mm, so it is designed to solve exactly the problem that is the subject of this thread. If you look up Cycles Grand Bois on Google, you can utilize
Google translate. The Grand Bois reproduction parts are all made to a very high standard.

PS…Measure your fork crown seat/crown race carefully as there is likely to be some hanky panky with the dimension from that era.

PPS….Oops…It looks like they are out of stock on the French threaded version, so no help unless they are restocked….