I have a 1980 Fuji America 18 speed road bike that needs to have the handlebar replaced. How do I determine the handlebar size? It appears that 26mm is the common size for older road bikes - but I do not have a micrometer to be able to take an accurate measurement.

  • 2
    Wrap thread around bar, measure it's length and divide by π. Mar 2, 2015 at 1:36
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    Purchase an inexpensive vernier caliper. I'm guessing you can get one at Harbor Freight for $4 or so. Mar 2, 2015 at 2:56
  • Either buy the tool to measure it, borrow the tool from a friend, or go to a LBS that has it. Mar 2, 2015 at 4:52
  • According to Sheldon Brown, the most likely size would be 25.4 mm. This page is a little dated though, and most road bikes will now use the 31.8 mm size. Again this should actually be something you should measure properly.
    – Kibbee
    Mar 2, 2015 at 10:34
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    (Actually, I checked and HF has a plastic vernier caliper for $3.99.) Mar 2, 2015 at 12:25

1 Answer 1


If you don't have good measuring tools (and know how to use them, but that's not too hard) it will be very hard to tell the difference between 25.4 mm and 26 mm – until you try to fit the bars in, then it will be obvious…

For a bike of that vintage odds are good (according to my recollection and Sheldon Brown's Crib Sheet) that the size is 25.4 mm.

So what you should do is by a set of 25.4 mm bars (ideally from a nice LBS that you want to support anyway) and see if they fit. If they don't and you can't return them get a 0.3 mm shim – Nitto and I think some other make them. If you're feeling flush get it with the bars just in case.

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    Some handlebars/stems will have their diameter printed on them. However it's worth owning a set of vernier calipers for all of the measuring in your life. They'll cost you about $10 for a set accurate to 1/500th of a mm. Here's how you read them. Dec 3, 2015 at 0:14

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