Hello all:

I have a vintage PX-10 that I am restoring. I bought a new old stock Stronglight V4 headset for the bike before I realized that these came in two different sizes. One size has a fork crown race that fits on a 27mm fork crown (French) and one has a fork crown race that fits a 26.5mm (Italian or professional) fork crown. I have the 27mm size but need the 26.5 mm size. I would like to purchase the correct fork crown race or a complete headset with French threads if anyone has on they would like to part with. I would also consider a trade for a complete headset or fork crown race in similar condition to mine.

I have been looking around but have found nothing in the usual places, so I an hoping that someone has one that they pulled off an old bike sitting in a drawer. Let me know if there are any leads.

How about this? It looks like it's mounted on a French Motobecane frame. I'd ask the seller for more details before bidding.

https://cgi.ebay.com/Campagnolo-Super...3A1%7C294%3A50

I really need to find the correct size Stronglight V4 so that my bike will be 100% original. However, a Campy may suffice until I find what I'm looking for. Thanks for the link, I'll check with the seller to see what size it is.

I think you would definitely have better luck finding a complete headset than just the crown race. If your headset is truly a complete original V4 headset, the bottom crown race would have a very uncommon "U" or "V" shaped channel into which the balls seat. It is not at all the same as the more common Stronglight P3 crown races which used a single concave bearing surface (like Campagnolo and most everyone else).

The V4 was originally designed to disperse the load over a greater contact area to offer longer life on brutal stage races over nasty Post-WWII French roads, and they were produced from the 1950s into the 1980s. Both the P3 and V4 used 5/32" balls, but I'm not certain whether the bottom headtube race would be compatible with a more common "normal" contoured P3 crown race.

If this is not making sense... Here is an early 1980s catalog page showing both the P3 and V4 headsets. They look just the same as images seen in 1950s catalogs, apart from use of a different style of top nut on earlier models.

https://farm4.static.flickr.com/3128/...f747e4f0_o.jpg

Since you already have the larger diameter race, I wonder if a thin "shim" - a narrow band cut from an aluminum soda can - wrapped around the crown race seat might work to fill in the gap. Seems to work as a "make do" solution for fitting 25.4 handlebars to 26.0 stem clamps... If you should try that, just make sure to wrap a full circle around - to keep the crown race centered and not pushed to one side.

Just a thought, not a professional recommendation.


Good Luck!

Thanks for the info and the Stronglight spec page. I actually had thought of a shim but I think I will go to a machine shop and have one precision made. I am hoping that someone will have what I need and see this thread instead of putiing in a shim. Still looking...

Knurling can increase the diameter of the seat.

https://www.bikeforums.net/archive/in.../t-128209.html

Actually knurling was the first option I considered but that is a permanent modification to the bike. Since I am trying to restore all original I would much rather just find the proper part. Thanks for the link, there are some intresting ideas.

Update: I have found a NOS 26.4mm V4 crown race set from someone I have dealt with before in Belgium. Will have it soon and then I can completly reassemble my bike.