Is it possible to upgrade an old Peugeot 10 speed to a thredless fork and stem?

What will i need?

you would need a new steerer tube and fork designed for a threadless system, new bearing, cups and shells, along with a new stem to fit on the forks. make sure your headtube has the same cup dimensions for the new system, or basiclly just get what fits right. it seems like a lot of money to spend to convert it. just don't like threaded headsets? you could get a killer new threaded headset for half of what you'd spend to get everything to change your bike over. thats just my opinion.

You can, but it will cost a significant amount of money.
You will need a new 1" threadless headset, 1" threadless fork, and 1" threadless stem. You will probably need new handlebars too.

You will also need a shop to take out your old headset and put the new one in, unless you want to spend even more money buying tools or makeshift tools.

Why do you want to do this?


You actually can't. The new headset will not fit an old Peugeot, because it will be French threaded, thus having a different dimensions on the threading.

I noticed some carbon fiber forks going pretty cheap on ebay
And i was thinking of upgrading if its cheap and possible. My peugeot similar to a px 10
it has neverex pro lugs and 531 tubing. I wanna make it in to a fix gear with modern components.
I understand that old french bikes have different sizes and threading to modern bikes.
so is it worth upgrading it? what do you guys think?

How old is your Peugeot? Until the early 80s Peugeots used metric diameter tubing and metric (aka "French") thread. As others have noted, the fork is probably metric thread, so unless the headset is shot or you have a burning desire to sink a lot of money into a new fork/headset/stem/bars (yes, the stem diameter and bar clamp diameter are also metric) you may want to hang onto those pieces at least. The BB shell is also likely metric, but you should be able to find a square taper axle of the proper length to suit a fixed gear conversion using your existing cups.

By the early 80s most French manufacturers switched to English threading, so you may luck out depending on the age of your frame, but the Nervex lugs argue against this possibility.

Keep in mind that high-end French components (Simplex LJ derailleurs, Ideale sddles, Maillard Professional hubs, etc.) are quite desirable for some collectors, particularly the well-heeled Japanese ones -- so don't toss them.

The PX-10 frame is regarded as one of the best riding production frames made, so IMHO at least it is worth hanging onto, even as a conversion. And please don't hack off the braze-ons and/or derailleur hanger or repaint it if the finish is at all reasonable. It will ruin the value of the frame should you ever decide to sell it. The metric nature of the beast means it will mainly appeal to a fairly small market already, and changing it from its original configuration/finish will likely lose even that market.