I've had a Gitane. Great bike. French bikes can be very confusing as to part dimensions. I think makers like Gitane have had different sizes for parts depending on where they were expected to be sold. But even then who knows. I wouldn't speculate with anything French, I would use a caliper and do an admiral Hopper and measure for a real answer on a particular bike.

And like Trailangel said, try and clean / service / adjust the one you've got now.

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