80's Campag Super/Nuovo Record Chainring/Sprocket Sizes

[Campaghunter]

I wonder if you guys can help with a few questions. I have a couple of early/mid 80's bikes I am restoring. Both Campag Super Record 1980's 52/42 front and 12 or 13 up to 21 max on the back. 5,6 & 7 speed, classic 80's Maillard, Regina etc.

As I am a bit older than I was, I was wondering about the lowest gears I can use, biggest difference on the front and max size on the back ? The mechs are Nuovo Record rear and Super Record Front, pat 81-83. I need as low as possible.

I also wondered if a later bottom bracket would work and the correct axle size ? Would a later C record, Chorus, Athena etc BB work ? The chainrings of some of these also look like they would fit and are smaller but has. Anyone done that ?

Sorry to ask so many questions but any thoughts much appreciated.

Thanks

 

[Midlife]

The smallest size chainring IIRC is a 41 for the Nuovo Record 144 BCD cranks, we ran 27 at the back. I think in theory the Nuovo record short cage could handle a 28 just........

Modern Campag are 130 BCD so can handle smaller chainrings but that means ditching those splendid 80's cranks.

Shaun

 

[Campaghunter]

Thanks Shaun, can you tell me what IIRC and BCD means please ?

Thanks

 

[Midlife]

IIRC means "If I Recall"......so from memory the smallest chainring is 41 from both Campag (never seen one) and Stronglight (seen them). As it's from memory it might not be correct. Google should throw up the correct answer

BCD is the size of the crank arms. The Older Campag is 144mm across and the follow on is 130mm across. The smaller crank arms mean you can use smaller chainrings.

Modern Compact cranks are 110 BCD and can take even smaller chainrings.......I have a feeling that my Basso has a 34 chainring but not sure as it's just a piece of 2012 machinery that gets me about LOL

Shaun

 

[torqueless]

BCD=(chainring) Bolt Centre Diameter. Distance from central axis of bottom bracket to centre of chainring bolt, x2
Yeah, you won't get much twiddlier than 42x28 with that combination of cranks/rear mech.

 

[bugloss]

You need a pair of these.....

 

[Campaghunter]

I do indeed.

Thanks for the info, very helpful

 

[Old Ned]

I think the cranks for use with the 41 tooth ring (like hen's teeth to find, very rare) had a groove across the top of the spider arm for the chain to sit on as the teeth are so low and close to the spider. A 28 is the max you would get to work in anything like a reasonable manner with Super Record (Nuovo Record can be better for some reason) but chain length can be critical as can the position of the wheel in the dropout and therefore the relationship of the large sprocket to the mech cage. Even with this the chain length might be to long for the little/little combination and might sag slightly. However, you never use this combination, do you. Some experimentation (ie, fiddling around) may be required.