Old Campy Freewheel and Derailleur
 

I own a 40-year old CIOCC 'Designer 84' that I ride occasionally just for grins. I want to replace the original 6 speed freewheel (13-20) with something a bit bigger such as 13-26 or 13-28. Three questions for you classic bike lovers:

1. Will the original Campy rear derailleur (see pics) accommodate the wider range? There are no serial numbers or identifiers on the derailleur that might help me look this up, so it seems I have to simply eyeball the length of the cage.

2. Could I go up to a 7 speed freewheel? The rear spacing of the dropouts and the downtube shifters will be ok. I wonder if the derailleur could handle the wider range.

3. Lastly, do you know of Campy-compatible manufacturers? Original Campy stuff from this era is insanely expensive. Specifically, I'm looking at this Interloc.

https://www.modernbike.com/product-2...iABEgLJEfD_BwE

Many thanks,
Kevin

That looks like a second Gen C Record RD. I don’t see a cable adjuster so assume you’re using friction shifting which makes things easier.

I don’t have experience with that particular RD, but have used 1st Gen C Record; however never pushed it harder than a 39-26 big small. I have used several Super Record RD’s set up with 39 or 42 ring up to 28 rear without any problems and on one bike even have a compact 34 chainring on a 26 rear. In your shoes I’d give it a go on the 13-28 but might have to be careful on big ring big cog shifts.

Secondly I’m not a huge fan of the IRD freewheels. They tend to have a reputation for short lifespans and this was born out with a very low mileage (<200) one making death screech noises on second day of Cino (admittedly harsh conditions). I’m partial to the older Suntour and Shimano freewheels, Dura Ace being my favorite. 6 to 7 speed depends mostly on the frame, most of the time it’s fine, but sometimes I’ll get chain rub on the chainstay on the small cog. I mostly use 8 speed chains, KMC as they’re cheap, come with a master link and friction shifting is pretty smooth.

Re:
 

As I recall, using a then-standard 42/52 crankset, the derailleur should have a cog size limit of 28 teeth. Any six-speed freewheel should work. If a seven-speed freewheel will fit the hub and frame spacing then it should also work but may require a thin profile chain like the Suntour "Ultra" line or popular "Sedissport" chains of the time. I'm not sure if a more modern 8-speed or 9-speed chain would work because the chains may be too narrow to fit over the cogs of a freewheel.

In my experience a 7s freewheel may require a longer axle and a spacer for the chain to clear the rear dropout. You may have to re-dish the wheel.

Both of you have been enormously helpful. All of your advice makes perfect sense and I'm grateful. I am embarrassed that I forgot to give you the chain ring details that have a huge impact on the RD. It is a 52/ 42, which should probably allow the RD to go to 28 in the rear. Many thanks, guys.

Measure between the dropouts, if 126mm you are golden for 7 speed. I seem to recall the C-Record being okay with up to 28 teeth, same as the other Super and Nuovo Record derailluers. A used or NOS SunTour, Shimano, or Regina freewheel shouldn't break the bank and will work perfectly with what you have, just pair it with an 8spd chain like Spaghetti Legs recommends.

A Campagnolo freewheel was extremely rare and very expensive in the 80s and known to be somewhat fragile. If that's what is on the bike, and it still works, I would remove it for safekeeping.

You will need the proper tool to remove whichever freewheel you have and end up with. Just a heads up, they are even less standardized than current BBs. I couldn't make out what you have from your pictures, but the brand is usually stamped on the outer cone of the freewheel.

I ran that very derailer with an 8s, 11-28t cassette, and it worked surprisingly well.

So using a 7s freewheel having modern HG-type tooth features can give very good shifting across a 13-28t range which is currently offered by Sunrace.

You will likely need a longer chain, and I believe there may be an adjustment feature at the mounting bolt which will adjust the "B-tension" to accomodate the 28t cog.
You won't have a lot of leeway in terms of chain length with which to alter the chain gap between the pulley and largest cog, but adjusting the axle position in the dropout will possibly allow either some chain length choice or at least some fine-tuning of the chain gap.

Some of the chromed Sunrace freewheels are very good-looking, here's a 13-25t:
https://live.staticflickr.com/5276/7...949e31c5_c.jpg

And here's a 13-28t made by Giang, axle spaced for only 124mm spacing:
https://live.staticflickr.com/7076/7...a4baae22_c.jpg

You can use your existing crankset with a 39 tooth front chainring, and a 7 speed rear freewheel from Dura Ace which might give you a largest rear cog of 28. This, paired with a new SRAM PC-870 chain should give you more range.

Other than my fixed gear bike, and my modern road bike, most of my riding over the years has been on Campagnolo C Record gear, so it's been a challenge to get much of gear range when limited by the short cage rear derailleur.

Lot's of good advice offered already, so hope this adds to it! If you need a smaller chainring send me a PM, might have an extra.

Thanks everyone. This has been great. There is a vintage bike shop here in Pittsburgh and he is now attaching a 13-28. New chain is on the way as well. I'll stick with the 51-41 up front for now. Also, I've decided to stick with the 6 speed setup. If I can get that 28 to work, that will make a world of difference on this bike. As I may have said, this is not my main steed. My regular rides are on modern bikes. But there is just something about this old CIOCC that I like to take it out from time to time, even on a reasonably fast group ride. It always attracts admirers.

Wisconsin19 offered an interesting idea about fitting a 39 on the chainring. I PM'd them but could not send them a photo (in PM) of the current chainring. My concern is whether there is a 39 that would fit the bolt pattern (see attached). I do not want to abandon this crankset if possible.

Thanks to all of you. Your advice might help my 70 year-old legs ride this bike around Pittsburgh a bit more often.

If I'm remembering correctly, that's 144 bcd. I think a 41t is the smallest you'll find. With a 135 bcd you can get a 38t

Pay attention to bolt ring diameter (BCD). Yours is 144mm. 39's are 135mm or smaller

Unfortunately no, that is a 144 bcd Super Record crank. TA makes a 41 tooth ring but that is the smallest you’ll get on there. I’ve cheated on some of my old bikes and put vintage looking alloy compact cranks on.

Maybe not quite what you're asking for, but there are special chainrings that can convert that 144mm BCD double crank into a triple crank with a 74mm inner BCD. Although a 74mm BCD can fit a inner chainring as small as 24 tooth, for best front shifting performance you'd probably want an inner chainring more like 32 teeth.

Here's one of the special "triplizer" chainrings from Red Clover:

https://www.redclovercomponents.com/..._42_Teeth.html

You'd likely also need a new front derailleur to handle a triple, but judging by the current derailleur you have friction shifters, which would work just fine with a triple front derailleur.

Once again, everyone, great advice. Thank you so much. I think I will keep it as is for now. A triple is an interesting option I had not thought of.