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Discussion Starter · #1 ·
I am looking to replace the stem and handlebars on my vintage 1970's Motobecane. The problem I am running into is that the french used 7/8" stems instead of the standard 1 inch. What can I do, besides buy a new fork, to make this switch work? One suggestion i got from sheldon brown was to sand down the new stem ever so slowly until it fit into the fork, what do you guys think about this? Do road handlebars need to be replaced like mountain bike bars, every couple years? These are the originals and I don't want them to brake while I'm riding. Thanks

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Unless they're cracked or bent, there's no need to replace the bars. I put a Cinelli stem in a Motobecane I had. I did the same thing Brown suggested. I clamped the stem in a padded vice, and used a file to whittle it down. Worked like a charm. Just ck it frequently to make sure you aren't taking too much off. I used that bike as my commuter for years.
 

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Mr. Versatile is right - no problem at all to sand the stem down. Also remember that the 7/8" and 1" designations are only nominal dimensions. The actual fork steerer inside diameters differ by only 0.2 mm. That's the thickness of a very thin piece of cardboard, so go easy on the sanding.
 

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Discussion Starter · #4 ·
?

by check it often to make sure I'm not taking off too much do you mean taking it out of the vice and trying to put it down the tube, into fork? sorry if I'm not getting my terminology right. What grit sand paper do you suggest? If this works this bike is going to be awesome, a mix of the old with the new. Thanks for the replies.

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Here's how I would do this:

Measure how far the minimum insertion mark is from the bottom edge of the stem and write that dimension down.

Start with wet or dry 80-grit emery cloth. Take the stem out of the vise often and try to insert it into the fork steerer. A good fit will have the stem go in, but not drop when you let go.

Finish with wet 400-grit emery cloth, then polish with automobile rubbing compound or toothpaste. Reestablish the minimum insertion mark with a shallow, barely visible Exacto knife score mark.
 

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wim said:
Here's how I would do this:

Measure how far the minimum insertion mark is from the bottom edge of the stem and write that dimension down.

Start with wet or dry 80-grit emery cloth. Take the stem out of the vise often and try to insert it into the fork steerer. A good fit will have the stem go in, but not drop when you let go.

Finish with wet 400-grit emery cloth, then polish with automobile rubbing compound or toothpaste. Reestablish the minimum insertion mark with a shallow, barely visible Exacto knife score mark.
Great advice!
 
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