BCD - DURA ACE 7400 SERIES

Campag Nuovo/ Super Record era (70's) and the numerous copies that came about....

Shimano, afaik, has always been 130bcd apart from modern compact and old mtb which is 110bcd. Theres others in mtb range.
 
Early Campag had 151 and some Campag Gran Sport were 144 according to Velobase.

Certainly early Campag / steel 3 arm Campag were an odd size.

Shaun
 
so it's like most things retro, manufacturers produced to there own spec but changes where made as the decades went by, i.e 144 for high end campag in the 70's but changed to 135 from the 80's onwards?
 
changes made due to trying to out-do the competition and the advent of 6 / 7 / 8 & onwards for freewheels & cassettes?
 
oops forgot to say 144 for Campag copies like Sakae Royal, Sugino, Gipiemme, Omas, Ofmega....

The changes seemed to be driven by the need to avoid duplication of gears with standard 52/42 doubles when 7-8 casetes started to arrive, henve the change to a compact crankset where a larger differential between big / small chainrings.

Shaun
 
My knowledge only goes back so far but initially large spiders were for stiff chainsets and men were men and did not need little inner rings; the standard for 144bcd was 42, 52 afaik. Shimano came along and introduced 130mm allowing smaller inner rings although the standard of 42, 52 did stay for quite sometime but 39,53 became the norm. Campag followed Shimano's lead and introduced 135mm to allow for 39t inner.

The advent of 110mm compacts (Shimano and Campag) allows for tiny inner rings down to something like a 34t.

The above is not official just my own conclusion....
 
All very interesting and I suspect someone a lot smarter than me did a lot of maths to create all of this - lot's of variance but principally it's all lead to most manufacturers providing the same options circa 2013 - all seems a long way round to the same destination?!

However, I have noticed Mavic tried to cover both bases with 130 & 144 - I know this as I bought some spare Mavic chainrings on the assumption that they would fit my 631 cranks - but no - they are for the 630 cranks!! that's how simpletons like me get confused :oops:
 
Early Mavic were a Campag look-a-like so are 144. Later ones are a lot more practical with 130. 38t is definitely possible with 130 - I know, I use them! Anything to get a few more less inches in bottom gear. You could always buy a new TA or Stronglight (Spa Cycles stock loads) and get them anodised locally in black. People used to do this all the time BITD when it was fashionable.

Goodness knows how we used to climb mountains BITD with only 42x24!

EDIT - just remembered, we were a LOT younger!
 
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