French Steerer Threads
Here is an email I received recently from Carles, with an interesting but difficult problem with his Vitus bike:
The 40 Year Old Problem
Carles’ issue is not so dissimilar to the one I had with a Jacotey fork steerer problem. In my case, I approached my local framebuilder who coud only recommend cutting the steerer and replacing it with one cut with a standard thread. It is a problem that really requires expert help, as very few people will have the 40 year old tools to retap or lengthen old French threads. A standard headset on a French steerer tube wont thread on properly, and an Italian headet will feel loose, even if not at first.
A French Threaded Locknut on a Standard Steerer
Problem Unsolved
It’s really strange to find a bike with a French threaded steerer and an Italian threaded bottom bracket. Yet, these things do happen. One of the caveats of buying an old French bike is always being aware of the condition of the threads. But it’s unlikely you’ll find damaged threads until you need to swap something or upgrade a part, and it’s only then that you are faced with a major problem. Who can retap or replace your damaged French threads?
Bikes Shops No Help
Most bike shops should have the tools to retap your standard threaded steerer ( for example the Park tool FTS-1 ), cutting 1-1/8 and 1-1/4 threads with relative ease. However, very, very few will have the French equivalent, because the old French steerers were of a slightly different size and thread: 25mm instead of 25.4mm, and 24tpi threading instead of 25.4tpi. These French steerers went obselete after 1982, so good luck in finding the tool, and even worse, finding an obliging bike shop or even frame builder.
The VAR 40 B
The tool all vintage French bike owners need in their tool box is a Var 40 B, which was the proper tool for cutting French steerer threads. I have seen a couple on Ebay this week, one in Spain for a princely sum, and the other incomplete, with just the handle and not the die. I also found a NOS or custom built 25mm die for sale, which could perhaps fit into the Park Tool handle or just as well not. All three examples are costly, but it would be so good to own a Var 40 B. I even wrote to a few die makers, but a custom-made die, a one-off, looked costly.
Var to Do
I trawled through some French classifieds for a good while, and did actually find a VAR 40 B in good condition, complete and useable. If fact, the seller also offered me a VAR 34, a head race press tool. In French it is called un Presse Cuvette De Direction. He offered me them both for half the price of those examples I mentioned on Ebay, but with the condition that he sent them to a French address. Damn. I did have one, but not anymore.
The Keyway
Solutions
I don’t know if there are some French bike shops or frame builders out there that can still do this job, but I’m sure there can’t be many anywhere in the world. If you don’t own the tool, then I can only imagine the solution would be to replace the forks for a pair of standard threaded ones. A new headset will be required, too, as the French headsets naturally won’t work and also have a keyway built in. It really could be worth investing in a VAR 40 B if you can find one, because without the tool, there’s no solution to the problem.
Update
Carles wrote to me recently and informed me that he has found a workshop in Spain which can extend his threads and enable him, therefore, to keep his Vitus fork. He has sent his forks to BCIMAX, which is a shop that specialises in vintage bikes and is based in Barcelona. That’s a very satisfying ending to a problem that could have nobbled a great bike project. The workshop can be contacted here: https://www.facebook.com/Bcimax/
Here are a couple of pictured of Carle’s lovely bike:
I am not a bike mechanic, but a motorcycle mechanic.
My analysis of the situation is this. It looks a bit simple.
If there are bike shops which have tapping tools, then it is making it more easy.
Most probably, these shops have tapping tools of threads that are commonly used.
Meaning, they sell headsets of the types of threads that their tools make.
I noticed that the new fork is still very long, and, cutting it to the right length will leave the tube blank or no thread. This means that there is no need to follow what was started as thread. Make a new thread which is common and for available headset.
Bike shops don’t have tools for tapping French threads anymore, that was the point of the blog. They became defunct in 1982.
Mr. Joselyn Agoncillo is correct, just cut the tube and have the shop tap it to standard. Easy peazy.
Recently I damaged the steerer threads on the fork of my ’73 Gitane Tour de France while mistakenly having a local bike shop install the top section of a Tange Levin headset.
A year before, at the advice of knowledgeable member of bikeforums.net, I had replaced the bottom half of the original, french-threaded Stronglight P3 headset with the Tange because it was the correct stack height, and nearly matched the vintage look of the P3.
Where I went wrong was having the “lbs” use the Tange upper section when the top section of the P3 failed.
The next 30 miles of riding were bliss, until they weren’t. Stopped at a nearby bike shop to get them retightened, but asked if he was familiar with French headsets & threading. I should have know there might be problems when the mechanic stated “headsets are headsets”. 7-8mm of threads at the top were stripped/mashed.
After a month of searching I found two frame builders in the US that address this issue, and I’m sending the fork to one of them this week. From what I understand, they’ll remove the upper, 1″ steerer section, ream out the top of the lower section, braze in a new upper 1′ section, and recut the threads using a lathe, not a die.
The frame builder he would use a lathe to cut either French or Standard threads, and but that using lathe was the way to go. He’s done this hundreds of times. He recommended standard, because I’m not married to originality and want to use the Tange.
I’ve attached couple of photos of the process, and of my damaged steerer.
BUT, I’m nervous about missing something here.
And If he can use a lathe, why is a Var20b even necessary, except to chase a slightly damaged steerer?
Any counsel would be much appreciated!
Hi, thanks for your interesting comment, and sorry to hear about your headset woes.
It sounds to me that your frame builder has the answer, using a lathe and cutting new threads as the damage to your steerer seems pretty bad. In these situations I think you need someone like him who has done it many times, and personally I would get standard threading as it will only make any future repairs easier.
I wrote about the Var tool as a possible way to solve these damaged threads problems, aware that most of us will have had no experience of doing this but hypothesising that perhaps chasing a couple of bad threads could be possible, in theory. However, an expert frame builder seems the best solution, because even if I had the correct tool I would be a novice at cutting threads and more likely to make some error and cause further damage.
I think your frame builder sounds like the way to go. In another post I had a pre’82 French steerer completely replaced by a good frame builder in the UK, to standard threading and it was a good repair. https://thevelocollective.com/damaged-steerer-threads-repair/
Hope it works out, let us know!