Actually, you can use pretty much as large an FW as you want, as long as you get the right chain length. The problem is that the RD must wrap the chain length difference between the Small-small combo and the large-large combo. So if you use a smaller large chainring, you can use a larger large FW cog and still shift OK. So a smaller outer chainring does make a difference.
As to 41T 144 BCD chainrings, they do most definitely exist. In fact, TA currently makes a very nice 41T 144 chainring. I have a couple in use on Campy NR cranks now, and they work fine. Genuine Campy 41T NR/SR rings also exist, although they are much rarer. I have one of these also. I have heard that the Campy 41T ring was originally produced for tandem cranksets, but I've never confirmed that.
Regards,
Jerry Moos Big Spring, Republica de Tejas
John Betmanis <johnb@oxford.net> wrote:
Kurt Sperry wrote:
> Most cranks are at or near the limit constrained by the BCD
> on the inner ring, so for most on topic bikes the only way to broaden
> the range down low is to use larger freewheel cogs.
That's exactly why a 40.5" bottom gear is the limit with the Nuovo Record with a 42T small ring and 28T big cog. I have heard of a 41T small ring for the 144mm BCD, but haven't seen one.
John Betmanis
Woodstock, Ontario
Canada