1987

I have mostly got old bikes, but on one from the 80s there is a peg/boss (I don't know what it's called) on the backside of the outer chainring.

When was this feature introduced?
What's it called?
Why? - protecting the chain from getting jammed behinde the crank arm?

Picchio Special

I believe the "pin" was introduced in 1978, with the CPSC changes made that year. And yes, my ubnderstanding is that it was intended to prevent the chain from being overshifted and jammed.

Chombi

I can live with those (CPSC mandated?) pins much better than those goofy front axle retainer clips and ramped dropout faces they forced on to bikes in the mid to late 80's pretty much overriding the quick release function of the front wheel.
I actually drilled and tapped an NOS chainring that didn't have one of those pins to transfer one from a worn ring before I installed it on my bike.

Chombi

fietsbob

51t and larger, perhaps, NGS rings did not , [perhaps.. not a <C> historian.]

I have a NGS 52 , flipped to be a middle on my 52,36t double .. no pin.

1987

Thanks
1978 CPSC modifications was also my guess. But the pin is not depicted in any catalog nor explained in text.

753proguy

The overshift pin was added around 1973 or so, I believe, way before the CPSC changes of 1977-1978.
Only road chainrings of 50 teeth or larger got the pin.

1987

Thanks 753proguy, interesting with another opinion and the best name for it so far "overshift pin". My vintage rides all dates before 1972 and those chainrings does not have the overshift pin. Can someone else get this time frame more narrow, right now it's 1972 (1973) - 1978.

If someone can find some reliable historical text source on the net.

Or can the overshift pin date from the same time as when Super Record was introduced, 1973 / 1974?
https://www.velobase.com/ViewComponen...m=122&AbsPos=8

Ex Pres 

I still think the pin came into use when the CPSC standards came out.
Reason? The crank arm was shifted slightly to the right away from the large ring in order to clear the CPSC mandated lip on the front derailleur cage. This provided the opportunity for a jammed chain.

(I've had an older crankset without the pin - but there's no telling the date of the rings on that crank, and it's no longer in my possession)

dbakl

My memory from the time was that it was originally a Super Record feature, but I could br wrong. I think its to keep the chain from getting caught between the chainring and the arm.

1987

Good points, both Ex Pres and dbaki. But we still don't have any real evidence.

Yes it could be a Super Record feature only, though I don't have any "modern" Nuovo Record chainrings for reference.

Campagnolo components catalog from 1982 (Olympic), has got these texts about CPSC modifications to the right crank arm and BB axles.
But no text about chainrings.





Unfortunately there is not much to read about the chainrings in the first catalog with Super Record, Campagnolo Catalogue 17 from 1974.

753proguy

Super Record was introduced in 1973. I've never seen a 50-tooth or larger Super Record road chainring without the pin. Has anyone? I'm sticking with my SWAG of 1973.

753proguy

The pin is most definitely present on both Record and Super Record road chainrings of 50 teeth or larger, beginning in (imo) 1973.

1987

Thanks 753proguy, you sound confident about this. And it's very likely that the pin was introduced with Super Record. Super Record had a lot of new features.

Otis

I'm pretty sure this was not a CPSC modification. For one thing, I've had a lot early-mid 70's cranksets go through my shop that did have the pin and the older style lettering on the webbing of the big ring. And second, it's a modification that actully makes sense and does not ruin the look of the ring so it can't be a CPSC mandate

1987

Thanks Otis. That has been my basic thought as well. The pin ads a feature, not like the CPSC stuff. 1973 is a good contender.

753proguy

I'll stick with 1973 unless someone can show me a Super Record road chainring of 50 teeth or larger without an overshift pin. I might even bet a half-million Lire on it....

I love it when I see an eBay auction for a 49-tooth 'Nuovo Record' 3/32" ring that says it is 'rare!!!' because it doesn't have the pin. The use of the word 'rare' (with exclamation points, of course) on feeBay is quite humorous to begin with, for that matter....

big chainring 

My '73 Motobecane LeChampion came with the chainring pin - Nouvo Record 52 tooth. It was a new Campy feature that year.

eschlwc

questions

should the pin on the big ring be facing outward, toward the arm and also hidden directly behind the arm? is that the correct position of the ring (with pin) on the spider? thanks.

repechage

Yes. The pin gets oriented there.

eschlwc

^ thanks.

Pars 

I had a post-CPSC NR crankset (bought new, around '84) that had the pin. My '73 NR crankset from my Raleigh (from an International) did not have it, though as mentioned it was probably older stock.

old's'cool

As an aside, I bought I believe it was a 48T Shimano W series ring off Ebay that had a pin on the same side that the chainring mounting holes were counterbored, so maybe it was meant to be an outer chainring. I installed it as an inner chainring, with the pin facing toward the frame, and was briefly puzzled when the pin hung up on the frame on the first test revolution. On the second revolution the pin was torn out of the chainring and I didn't worry about it any more.

eschlwc

^ ha!

Timlayla

The peg of pin was placed on the outside of the chainring so if you change gears and the chain goes over and off the chainring, rather than having to stop to put the chain back on the chainring, the peg or pin catches the chain and all you need to do is continue pedaling to get the chain back on the ring.

nomadmax 

2012