Beginner Question. Is a 31.6 front derailleur same as 31.8?
12-09-08, 08:32 AM
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Beginner Question. Is a 31.6 front derailleur same as 31.8?
Quick beginner question. Is a 31.6 front derailleur the same as using a 31.8? I'm in the midst of trying to piece together my first proper road bike and my lack of search skills has failed me. Is the 31.6 and 31.8 front derailleur options the same as having a 31.7 and 31.8 handlebar clamps (essentially the same)?
note: For a little more info. Im looking to buy a Motobecane Le Champion frame set to go with a SRAM Rival groupo. The Rival derailleur option is 31.8 and the frame set specifications list a 31.6 is needed.
note: For a little more info. Im looking to buy a Motobecane Le Champion frame set to go with a SRAM Rival groupo. The Rival derailleur option is 31.8 and the frame set specifications list a 31.6 is needed.
12-09-08, 08:49 AM
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Seat tube outside diameters come in 1-1/8" (28.6mm), 1-1/4" (31.8mm) and 1-3/8" (35mm) diameters.
Be sure that you are not reading the seat post diameter instead of the seat tube diameter.
I prefer to buy a clamp-on adapter and use a braze-on FD.
Be sure that you are not reading the seat post diameter instead of the seat tube diameter.
I prefer to buy a clamp-on adapter and use a braze-on FD.
12-09-08, 08:59 AM
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Thanks DaveSSS. Anyways, to quote the sales page of the frameset
"Front Derailleur: 31.6 mm Shimano Ultegra
Seat Post: 27.2 mm"
It comes with a Ultegra derailleur, but I wanted to be sure I could replace it with the Rival one Im getting (might as well keep everything uniform). As for a clamp on adapter, that sounds good. May I ask why you prefer the adapter as opposed to a built in clamp?
"Front Derailleur: 31.6 mm Shimano Ultegra
Seat Post: 27.2 mm"
It comes with a Ultegra derailleur, but I wanted to be sure I could replace it with the Rival one Im getting (might as well keep everything uniform). As for a clamp on adapter, that sounds good. May I ask why you prefer the adapter as opposed to a built in clamp?
12-09-08, 09:19 AM
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Thanks DaveSSS. Anyways, to quote the sales page of the frameset
"Front Derailleur: 31.6 mm Shimano Ultegra
Seat Post: 27.2 mm"
It comes with a Ultegra derailleur, but I wanted to be sure I could replace it with the Rival one Im getting (might as well keep everything uniform). As for a clamp on adapter, that sounds good. May I ask why you prefer the adapter as opposed to a built in clamp?
"Front Derailleur: 31.6 mm Shimano Ultegra
Seat Post: 27.2 mm"
It comes with a Ultegra derailleur, but I wanted to be sure I could replace it with the Rival one Im getting (might as well keep everything uniform). As for a clamp on adapter, that sounds good. May I ask why you prefer the adapter as opposed to a built in clamp?
12-09-08, 11:25 AM
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I've seen manufacturers list the FD clamp diametre as 31.6mm, 31.8mm and 32mm. They are all referring to 31.8mm.
Buying a braze-on derailleur with a clamp will allow your to swap your derailleur to a larger number of frames. If your new frame has a braze-on, just remove the clamp. If it's a 34.9mm clamp-on, just buy a new clamp.
Buying a braze-on derailleur with a clamp will allow your to swap your derailleur to a larger number of frames. If your new frame has a braze-on, just remove the clamp. If it's a 34.9mm clamp-on, just buy a new clamp.
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