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Front derailleur clamp size - 32mm or 35mm???(6 posts)

Front derailleur clamp size - 32mm or 35mm???jamie brown
Jun 10, 2002 2:06 PM
Replacing my front derailleur on a three year old Serotta Colorado. Anyone know (off the top of your head ) what the clamp size is?

Is it the inside diameter of the clamp that is measured, or the diameter of the seat tube, or what?

re: Front derailleur clamp size - 32mm or 35mm???Jekyll
Jun 10, 2002 2:21 PM
Measure the OD of the seat tube where the derailleur will sit.
Measure the seat tube diameter.the dad
Jun 10, 2002 2:22 PM
That's always safer than taking the word of somebody you don't know.
1 1/8" = 28.6mm
1 1/4" = 31.8mm
1 3/8" = 35.0mm
Measure the seat tube diameter.jamie brown
Jun 10, 2002 3:08 PM
Excellent - thank you.
If you don't have a caliper,the dad
Jun 10, 2002 3:13 PM
take a big crescent wrench and gently close the jaws around the seat tube. It doesn't have to be perfect, we're talking 1/8" here. Then you can measure the distance between the jaws with an ordinary rule.
measure circum. then get DiameterOld_school_nik
Jun 10, 2002 4:22 PM
Take some dental floss (or string if you live in England) and wrap it around your seat tube where the old der was mark the length on the string with a pen then stretch out along a ruler and measure it. If you only have Inches times by 2.54 to get metric or 25.4 to get mm

Diameter = Circ ÷ 3.14

there you have it