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The steerer in the French bike I'm restoring has about .2mm less diameter than "regular" ones. With some grease, I manage to fit the "regular" cinelli stem I will use into the steerer. (Mine is the opposite problem as this.)

I'm inclined to I leave it thus. What are the odds that stem and steerer will freeze after some time, making removal hard/impossible?

The alternative is to sand down the stem to get a more easy fit. Downside is that sanding means the end of the stem's very nice looks, forever.

I will be grateful for anyone with advice to offer.

  • The linked problem is attaching handlebars to a stem. It sounds like in this case you're putting a too big quill stem into the steerer tube, which is a different problem. – Batman Sep 13 '15 at 2:00
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    My suggestion is to read this. – Batman Sep 13 '15 at 2:03
  • Thank you @Batman. Sheldon Brown has very good info, and I got the idea of sanding down from him. But he won't address the case where the stem barely fits... will it get stuck forever after some use? Will grease suffice to avoid this? I wish to avoid sanding... – emagar Sep 13 '15 at 2:43
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    Well, if it barely fits it fits (unless you hammered it in or something, in which case you could have damaged something). Periodically removing and greasing are pretty much the only way to avoid the freezing. – Batman Sep 13 '15 at 2:52
  • No hammering, just slight force to slide it in. I'll have to remember greasing/cleaning more often than I usually do. I should add the Sheldon Brown is the man. – emagar Sep 13 '15 at 3:33
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As noted in the article linked by @Batman. French stems are .2 mm smaller than the 22.2mm 1 inch steerer quill standard.

Options are to replace the stem with a 22mm stem, sand down a 22.2mm stem to 22mm, or replace the fork (not recommended).

Article text follows:

Many higher-quality French bicycles of the '70's came with AVA brand bars and stems. These have a reputation for failure, and should be replaced. French stems differ both in the size that fits into the steerer, and the size of the part that clamps on to the handlebar. Thus, if you want to replace the handlebars on a French bicycle, you will probably also need to replace the stem.

French stems are 0.2mm narrower than others where they fit into the steering column. A standard 7/8" / 22.2mm stem won't usually fit. In many cases, the limiting factor for fitting the stem in will be the headset locknut, rather than the steerer itself. Try removing the locknut before sanding down a stem. If the headset locknut is slightly tighter than the steerer, it can be enlarged easily with a small grinding wheel.

In cases where the stem really won't fit into the steerer, a few minutes' work on the stem with sandpaper will usually do the trick. Wrap the sandpaper around the stem, grip it with your hand, and turn the stem round and round until it fits. You only need to remove 0.1 mm, which is 1/250", not much at all! [This needs to be a quill-type stem, which inserts into the steerer tube, and an aluminum alloy stem, not a steel one -- from which you would be removing chrome plating, leaving it vulnerable to rust. Another approach is to replace the fork and the headset with ones with standard British/ISO dimensions. This is possible, as French head tube bearing race dimensions are 30.2mm, the same as British. You could use a standard 22.2 mm quill stem, or a threadless headset and a 1-inch Aheadset-type stem. Also, an adapter is available as of 2014 to fit a 1 1/8" Aheadset-type stem to a French fork.-- John Allen]

If you convert from a French stem to a standard one, you will also need to replace the handlebars, which are a different diameter.

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Your main concern of the stem becoming stuck, is valid. It requires you to remove the stem and re-grease it more often than you otherwise might. I'd recommend twice a year minimum. Sanding the stem is a viable option, first determine how high you need the handlebars to be, then rap tape over the part you are sure you want exposed above the locknut of your headset, then sand for 10 minutes, and check if it fits. You may need to sand the wedge as well. If it doesn't fit yet, sand it again and check every minute or so, it usually takes about 15 minutes or so. I've had AVA stems fail before and I was very lucky, Cinelli, TTT, and others made stems for French bikes and 25.0 handlebars, but they're getting hard to find. I prefer sanding Nitto stems as they are well made and have models to get the bars up higher for riders who need a more upright position.

  • Welcome to SE - we'd normally tell new people to read the tour but your answer is relevant and practical and actually answers the question. Nice first answer! – Criggie Nov 28 '17 at 10:05
  • Welcome to the site, Mark! – David Richerby Nov 28 '17 at 11:07

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