I am doing L'Eroica (205km) in October this year. The chosen (pre-1987) bike is a Colnago Super with super record group set.
Issue - the chain set is 52/48 (i.e. road set up) and even with the highest sprocket rear block (28) i can find, I will be walking up more hills than I would like, which with old style shoes and cleats is not good for comfort or time.
Talking to Spa cycles in Harrogate, they inform me that there are no lower chainring options for the SR group set - their solution (quite good) was to remove the SR chainset and for this event, use a cheap (£34) stronglight compact (48/34).
This lack of "period" chainset is niggling me - I wondered if there were any grey beards out there who might have another take on this? Surely there are campag chain sets that were made with lower ratios?
T

well, if you want it to stay vintage get a vintage compact crankset. or, run a campy rally rear mech with a 34t large cog.

You can definitely get a 42T inner ring, which will help a lot. Whether that would be a Super Record ring or not, I don't know. But it will look the part.

You could get a period-correct TA compact double-- they made them throughout the Campy SR period, and it would open up a lot of gearing options. I recently replaced the Campy NR 52/42 chainset on my Mercian with a period TA 48/36 setup. It still looks the part, but more importantly, the bike better fits my needs.

If you are willing to let someone put a drill to your vintage Campagnolo crankset, Elliot Bay Bicycles can also make a triple out it: https://www.flickr.com/photos/8379107...7622574585267/. Or you can also hope to find some TA triplezer rings, as discussed in this thread: https://www.bikeforums.net/showthread...riplizer-rings. In either case, you'll need a longer spindle, and a long-cage RD as well. If the gearing is sufficient for regular use, a cheap compact crankset is probably a good temporary solution for L'Eroica. Have fun! I'd love to be able to do this event some time.

Like others have said, you can get a 42 on there. There are even 41's, but they are somewhat rare and expensive. Last year my lowest gear was a 42x28 using Campi NR. I cleared all of the steep stuff, but I was pretty close to my limit, and I am an active Cat 2 racer when I'm not being a retro rider. The two guys I went with also cleared the hills, one had the same gear as me, the other had a 39x31 on some old DA stuff. Both of them are flyweight climbers. Most people were walking the worst hill. It is a series of 7 very steep ramps a bit after the mid-point of the ride. My friends are planning to return next year. They are going to cheat and use a Velo Orange compact.

Get a period-correct Zeus crank, which will accommodate down to 36T ring. Here's mine set up with 48-36 rings:

Thanks for the help/reassurance. Will look for 42 inner ring which with 28 rear block should (with grunt force) be enough. T

Probably a good choice. The L'Eroica organizers are pretty strict re the use of modern components I think. Would really suck to get there and find your bike is ineligible.

Any chance of seeing your L'Eroica Colnago in pictures?