Are French and Standard Headsets Interchangeable?

Repairing Old French Threads

If your older French bike has damaged threads, you have a problem. French parts are becoming hard to find, and not many bike shops will be able to retap your pre-1982 threads on your bottom bracket shell and fork steerer to the same specifications. An older French headset and bottom bracket has a threading of 35mm x 1mm, which is now called “obsolete”. As is the old Swiss standard. So this means that tools like the Park Tool BTS-1, for example, can’t be used to repair your old French threads, if you want to keep them. “Better”, many bike shops will say, “to retap your threads to the standard 1.37″ x 24 tpi”. Seems true.

 

 

Having to Buy New Parts

 

If you do get your French fork or bottom bracket retapped to standard threading, you have to be aware that you will require new parts that fit on your new threads. Naturally, I wanted to keep the pressed-on races that were part of the original French headset that was on my frame. Pressing on new races requires a professional tool that I don’t own. For curiosity, I tested my French threaded locknut on my newly retapped steerer, and it would only turn on the first thread. At that point, it would stiffen and if forced to rotate, would start damaging the threads. So a complete new headset was required, so I was told by three different bike shops. But that isn’t entirely true.

 

 

 

Some French Parts are the Same as Standard

 

When I looked at the pressed races on my Jacotey headtube, they looked identical to the standard cups of a British headset I had just bought. You can see from the picture above, they seem identical. This made me rather skeptical when bike shop owners were telling me “oh mate, you’ll have to buy a complete new headset; the old French one won’t fit”. None believed you can “mix and match”, as it were. They predicted, if I kept the French races, a gap in the races, ball bearing problems and other horrors. But they were wrong. Here’s the fact:

 

• The upper headtube race and lower headtube race are exactly the same size as standard races.

 

 

 

 

Watch Out for your Washers!

 

Another difference between French headsets and standard ones is a small one, but typically important and annoying: the washers they use are different and are not interchangeable. This is because older French steerers were made with a small flat, which the matching headset washer fitted. Standard steerers, by contrast, have a “grooved keyway”, which meant that the matching washer had a small stub to slide down the steerer. In my case, I had neither; my new fork column was without flat nor grooved keyway, so needed just a round washer.

 

 

Ebay Mistakes and Further Complications

It was very frustrating when I received my new British threaded, 1 inch headset through the post from an Ebay seller. As soon as I opened it, I could see immediately the job of installing my new forks was delayed. The Ebayer had sent me a threadless headset instead of a threaded one. Typically, this happened on a Saturday. I had to wait all weekend to send it back to him, but fortunately the seller made amends quickly and sent me the correct headset, which arrived on the Tuesday. So now I just needed the locknut, adjustable race and bearings from it to install my forks, right?

 

 

It’s Not Over Yet..

Here is something else I didn’t consider when I had a new column fitted to my forks: the steerer column length. Doesn’t it make a lot of sense?? It must be crucial to have the steerer column of similar length to the original. This completely bypassed me in my enthusiasm to get this bike on the road. The upshot was, when I finally started screwing on the adjustable race and locknut of my new standard headset on to the new steerer, I realised the column was slightly longer than the old column. This meant that I needed more washers to stop the steerer sticking out of the headset! What’s more, I required washers that had no flats or nubs in them.

 

 

Grinding

 

Unless you have some headsets washers lying around that perfectly fit your steerer, you can solve the problem of an ill-fitting washer by grinding it. I took a French washer with its small flat, and ground this flat down with a small file, allowing it to fit onto my steerer. Even though the French washer was made to fit smaller French steerers, which are 22mm, a little filing around its diameter will easily help it slide on to the larger standard 22.2mm. I did the same with an standard washer: grinding off the nub for my round steerer helped it slip on and helped secure the headset without any steerer protrusion.

 

 

Dimensions:

 

French

Cups: Outside Diameter:                 30.2mm

 

Standard

Cups: Outside Diameter:                 30.2mm

 

French

Crown Race Diameter:                    26.5mm

 

Standard

Crown Race Diameter:                    26.4mm

 

French

Steerer Outside Dimension:               25mm

 

Standard

Steerer Outside Dimension:                  25.4mm

 

French

Steerer Size:                                 22mm

 

Standard

Steerer Size:                             22.2mm