Old Motobecane Seat Post Size
04-08-21, 06:10 AM
#1
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Old Motobecane Seat Post Size
Does a Motobecane of late 70s or early 80s come with a 25.4mm seat post? I want to upgrade my seat post and saddle, but have got no caliper to measure, don't know the model, neither cannot find the serial number on it! Help please!
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04-08-21, 06:29 AM
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There is no way to tell what size seatpost this is unless you know the model and year and someone here has the same bike. It can be difficult to tell seat post size even with calipers. Take it to a shop. They have the tools to measure this.
04-08-21, 06:47 AM
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You should be able to measure within 0.2mm of the correct post size without a caliper.
Cut a strip of paper roughly 1cm wide by 10cm long.
Wrap it tightly around a clean, unmarred section of the post, so that it overlaps itself, with the edges aligned.
Mark where it overlaps with a very sharp pencil.
Unwrap and measure the longer of the two distances, from one end to the mark.
This measured distance is the circumference of the post and you should be able to accurately measure it to within 0.5mm. Divide this by pi (3.14) to get the diameter, which should be accurate to within 0.2mm. Perform the measurement a few times, to ensure the result is repeatable.
Cut a strip of paper roughly 1cm wide by 10cm long.
Wrap it tightly around a clean, unmarred section of the post, so that it overlaps itself, with the edges aligned.
Mark where it overlaps with a very sharp pencil.
Unwrap and measure the longer of the two distances, from one end to the mark.
This measured distance is the circumference of the post and you should be able to accurately measure it to within 0.5mm. Divide this by pi (3.14) to get the diameter, which should be accurate to within 0.2mm. Perform the measurement a few times, to ensure the result is repeatable.
Last edited by T-Mar; 04-08-21 at 06:50 AM.
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04-08-21, 10:08 AM
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New digital calipers on eBay are like $4.
