Are braze-ons standardized?
08-06-09, 05:29 PM
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Are braze-ons standardized?
I have a quick question that I think is pretty straight forward. Searched the forums and couldn't find an answer so here goes.
Are front derailleur braze-ons the same across all bikes and derailleurs? I have an older Cannondale that had a brazed on FD. It was attached by two vertically aligned screws, maybe about a half inch apart. I am buying a 105 FD braze-on and want to make sure it'll fit appropriately. Thanks!
Are front derailleur braze-ons the same across all bikes and derailleurs? I have an older Cannondale that had a brazed on FD. It was attached by two vertically aligned screws, maybe about a half inch apart. I am buying a 105 FD braze-on and want to make sure it'll fit appropriately. Thanks!
08-06-09, 06:22 PM
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08-06-09, 06:39 PM
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Compact (road double) crank versus standard (road double) crank.
Standard road crank has (typically) a 39 tooth small chainring and a 53 large, with a bolt circle diameter (BCD) of 130mm.
A Compact crank has (typically) a 34 tooth small ring and a 50 large, with a BCD of 110mm.
If you buy a road bike that uses a braze on front derailer hanger and has a standard road crank, the position of the braze on hanger and the front derailer is set to allow correct derailer position for that particular BCD crank.
If you attempt to change to a compact crank, you need to lower the front derailer for correct shifting. Having a braze on hanger set to standard may not allow the derailer to be positioned low enough for the derailer to work.
Sheldon has this to say:
https://sheldonbrown.com/glossary-b.html
Steve B.
Standard road crank has (typically) a 39 tooth small chainring and a 53 large, with a bolt circle diameter (BCD) of 130mm.
A Compact crank has (typically) a 34 tooth small ring and a 50 large, with a BCD of 110mm.
If you buy a road bike that uses a braze on front derailer hanger and has a standard road crank, the position of the braze on hanger and the front derailer is set to allow correct derailer position for that particular BCD crank.
If you attempt to change to a compact crank, you need to lower the front derailer for correct shifting. Having a braze on hanger set to standard may not allow the derailer to be positioned low enough for the derailer to work.
Sheldon has this to say:
https://sheldonbrown.com/glossary-b.html
Steve B.
