hammer11

From center of BB. Where should this be for standard road position? Anyone got one they can measure?

Thanks in advance!

unterhausen

i don't think we usually call it a derailleur tab. What is it that the derailleur tab does?

Are you talking about the front derailleur bracket braze-on? If so, that's a little tricky, and you have to decide what range of chainrings you are going to accommodate. Shimano and Campagnolo both have technical drawings for their front derailleurs

Eric Estlund 

I often call it a derailleur tab.

Take a look at the published spec, as well as the dimensions of your particular braze on and balance those with the gearing range for the crank sets you hope to use.

unterhausen

depends on if you want to use both a 53 or a 50 (144 looks good), or if you think you will only ever use a 53 (146mm will center with a 53). These are shimano numbers. Campagnolo is a bit different.

e-RICHIE

for a typical outside ring of 53t the center to center measurement is 148mm-150mm.
it also depends on the changer you are using atmo.

Live Wire 

Many Shimano specs and tons of good info from Peter Verdone here:
https://pvdwiki.com/index.php?title=S...mebuilder_Info

hammer11

Perfect thanks.