FD clamp size = ST OD?
02-08-12 | 02:17 PM
#1
Thread Starter
Senior Member
Joined: Aug 2011
Posts: 1,302
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From: NYC+NNJ
Bikes: i don't have a bike. a few frames, forks and some parts. that's all
FD clamp size = ST OD?
i know 28.6 is sorta 'generic' FD clamp size.
confused when i roughly measured the seat tube of my frame, the outside diameter appeared to be around 27mm? (didn't do it properly, but it was obviously not 28.6).
so what is the clamp size really relevant to?
thanks!
in case discussed previously, would appreciate the link as well.
confused when i roughly measured the seat tube of my frame, the outside diameter appeared to be around 27mm? (didn't do it properly, but it was obviously not 28.6).
so what is the clamp size really relevant to?
thanks!
in case discussed previously, would appreciate the link as well.
02-08-12 | 02:26 PM
#2
Senior Member
Joined: Nov 2004
Posts: 23,212
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A standard, C&V seat tube is 28.6mm except for French/metric, which is 28mm. Many older, non-derailleur equipped bicycles have 25.4mm seat tube. I'm assuming this is a measurement error and you do not have calipers. If so, cut a 5mm by 100mm strip of paper and wrap it tightly around the seat tube, in a cleaned area. Mark where the strip overlaps. Remove the strip, measure from the end to the mark and divide this measurement by 3.14 to get the diameter. Repeat to verify accuracy.
02-08-12 | 02:34 PM
#4
Thread Starter
Senior Member
Joined: Aug 2011
Posts: 1,302
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From: NYC+NNJ
Bikes: i don't have a bike. a few frames, forks and some parts. that's all
that's what i thought w no doubt.
i didn't use caliper. just eyeballed with my metal mm ruler.
will measure it properly again. hope it was just a mistake.
thanks!
i didn't use caliper. just eyeballed with my metal mm ruler.
will measure it properly again. hope it was just a mistake.
thanks!
02-08-12 | 05:46 PM
#5
multimodal commuter
Joined: Nov 2006
Posts: 19,810
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From: NJ, NYC, LI
Bikes: 1940s Fothergill, 1959 Allegro Special, 1963? Claud Butler Olympic Sprint, Lambert 'Clubman', 1974 Fuji "the Ace", 1976 Holdsworth 650b conversion rando bike, 1983 Trek 720 tourer, 1984 Counterpoint Opus II, 1993 Basso Gap, 2010 Downtube 8h, and...
If you don't have a caliper, you can measure the circumference and divide by pi.
02-08-12 | 07:02 PM
#6
Senior Member
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From: Thunder Bay, Ontario, Canada - burrrrr!
Bikes: 1958 Rabeneick 120D, 1968 Legnano Gran Premio, 196? Torpado Professional, 2000 Marinoni Piuma
Get a caliper! They come in handy time and again, plus you do not have to buy the best one on the shelf.
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02-08-12 | 08:44 PM
#8
Unimatrix Zero
Joined: Sep 2009
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mine was $10 shipped from amazon, and I've used it about 300 times in the past 3 months. fwiw, i'm using a 28.6 clamp on FD on a french frame... went around it with 2 layers of electrical tape first. it seems good so far.
