Campy Gran Sport RD - **********?
 

Does anyone have experience with getting a Campagnolo Gran Sport rear derailleur to work properly? Should I dump those old school idler pulleys? Any suggestions will prove helpful.

For the life of me, I could not get my sixties something Gran Sport rear derailleur to work. I could use a bit of advice, if someone knows what's up...
https://cimg7.ibsrv.net/gimg/bikefor...fcb33cab2a.jpg

As found, the derailleur worked just fine and was very quiet, under load, on this 13-17 freewheel...
https://cimg3.ibsrv.net/gimg/bikefor...2a54314d7a.jpg

Being unable to push those teeny-weeny gears, I opted for a 14-24 system and that is when the poo poo hit the fan...
https://cimg5.ibsrv.net/gimg/bikefor...ecbfde1def.jpg

Under even the slightest load, the noise was horrible and, for the life of me, I would have sworn that the noise was coming from the crank/chain engagement. I aligned the frame and drops. I aligned the derailleur hanger. I tried different wheel sets with different freewheels (14-24). Opened, checked and rebuilt bottom bracket. Tried a different crank set. Installed a new chain. No luck, the system was still very noisy.
https://cimg3.ibsrv.net/gimg/bikefor...bc714b1559.jpg

So, finally, just before I was about to forget about the project, I installed a different rear derailleur (Shimano SIS)...
https://cimg3.ibsrv.net/gimg/bikefor...a86d8aca3a.jpg

Perfect, noise gone and everything working smoothly...
https://cimg1.ibsrv.net/gimg/bikefor...133452b385.jpg

So, though a long ways from where I intend to go with the Torpado, it is working, road worthy and safe to ride. The bike is now fitted with a 700c fork (I replaced the "as found" after market 27" fork) and installed a set of 700c wheels. I really do like this bicycle but has it ever been a pain to get sorted out...
https://cimg7.ibsrv.net/gimg/bikefor...f643aa0ef4.jpg

From your pics there is a difference in the number of free links between the top idler pulley and the sprocket. It may be that the number is so few that the link contacting the sprocket tooth when it starts engaging has not yet become free of the idler pulley; you could well get a click every time that happened.

A trick you may not yet have tried is one of those hanger extender gizmos, that would get a longer chain run between the idler and the sprocket. It might also be possible to fiddle with the chain length and get a similar change.

I have had two of these rear mechs to play with and they both were loose in the knuckle pivots. Quieter when dirty (filled the voids); did you clean that as well?

randyjawa In the first picture, it looks like the spring is in backwards. the loop should be sliding along on the inside of the outer plate not the edge. Loop is oriented 180 off.
https://live.staticflickr.com/7369/1...0a5bca59_c.jpgLC_RrDrl_05 on Flickr

Try sliding the axle rearward to increase the distance between the sprocket and the jockey wheel.

FWIW, I have a Nuovo Record RD on my MK IV. It is a rider, not a show piece so right off I ditched the original Campy jockey wheels - almost no teeth and cracked anyway. I installed contemporary plastic wheels. I also ditched the old school chain and FW. Now has Suntour Ultra 6 spd 14-28 and a 9 spd chain. R wheel about in the middle of the DO slot. As reliable and quiet as a sunrise. Just snicks from gear to gear, up and down, with rarely any trim needed.

In in the past 6 years, no one has crouched down to inspect my drive train and berate me for non spec parts. I just enjoy the ride, often.

I gave up on mine on my 64 Frejus also. I swapped in some Japanese idlers to no avail. The chain wrap was also just at spec and no more as is not the case with other posters with better luck. I finally switched it out for a vintage Suntour 7 and quit fighting it. Oh well.

That's normal; Gran Sport spring has an extra loop so you can pop it out with your thumb, that's what you see. The load-bearing loop is inside where it should be.

Randy, your post provided the nudge I needed to update my Gran Sport pulley thread. You might want to look at my most recent post on that thread and check to see if your pulley slots are aligned with the nubs on the cage plates.

Also, these derailleurs are fifty plus years old. Some of them have lived a hard life. One of mine was giving me the sort of trouble you describe because the pulley cage was out of alignment. (two pulleys were not running in exactly the same plane) A rather crude adjustment to the lower pulley cage with a 10" crescent wrench quieted it right down.

Brent

I appreciate your educating me!

Another issue with the steel pulleys. The cones tighten up quite a bit when the pulley bolts are tightened. A pulley that spins nicely when out of the cage can stiffen to the point that it doesn't spin when it is installed in the cage and the bolt is tightened.
Brent

Indeed. Blame dyslexia?
The jockey wheels are... "worn" exchange for some decent Campagnolo plastic or Somafab replacements.
Then check the position of the jockey cage return spring, there are a few options, make note and try the one that helps best.
This is assuming there is little or no play in the mechanism.
But that Spring orientation....

You should probably do what many thousands of cyclists have done before you: Replace it with SunTour. Even the lowliest model will shift better. Or Shimano Crane if you want the early 70s upgrade.

I usually side with Suntour Neal, but I'm also wondering if one of those Wolf Tooth thingies would help with the bigger sprockets. That or a set of those repop Rally cages if they'd fit this RD. I can't remember which Gran Sport they'll fit.

I've had these GS derailleurs on several bikes, and I think most of them probably had something like 14-24 freewheels. I don't recall having the noise problem you describe, but if the derailleur was quiet with the 13-17, but is noisy with the 14-24, then I would guess the upper jockey wheel is getting too close to the bigger freewheel cogs. The GS should be able to handle a 26, but it may require sliding the rear wheel all the way rearward in the dropout slots (remove the adjuster screws or at least the springs). Shortening the chain will also help, as this will pull the upper jockey wheel away from the freewheel as you shift onto the larger cogs. If neither of these changes helps, then maybe there is a jockey wheel alignment problem as someone has suggested, but then why did it work fine with the 13-17?

That Shimano is loads better than the Campagnolo one, so just leave it there. From the picture of the Campagnolo with the chain on the biggest cog, it looks like the top pulley is pushing the chain onto the cog, and the pressure is making the noise. Or something. But just take that derailleur and put it in a display case. Or donate it to the disraeligears guy to document and study.

As some of you might know, I always work towards "original when street restoring my bikes. Hence, my goal is full Gran Sport and working properly...

Now that is something that I did not look into. Great advice and easy enough to check. My intention is to rebuild the Gran Sport and, hopefully (definitely), use it. I have, honestly, never run into this problem before and the noise, telegraphed from the rd to the crank set, proved my nemesis - so far. What most amazed me, and still does, is the way the noise telegraphed from the rear derailleur to the crank area.

They don't fit on any GS without modification. Bob Freeman (previously of Elliott Bay Bicycles and Davidson) was the first person (that I know of) to make Rally repops, and he was the one who got Merry Sales to make and distribute them. IIRC, his original hand-made ones were for GS, and since then he has modified the Soma ones to mount to GS. He's officially retired (I believe) but still does this stuff as a hobby.

I haven't seen the ones he's modified for GS, but I assume it isn't too hard. The GS bolt is larger than a NR/SR, so you just need to drill the hole larger and tap it, then drill a small hole for the tail if the spring. A GS has 3 holes for different amounts of spring pre-load, so you could drill 3 (or more), or just one if you know where you want the spring to go.

If you want a stop to keep the cage from rotating too far when the wheel is taken out, then that's another task. But the stop isn't necessary at all while riding, so you can just leave it off. It's just a little more awkward putting the wheel back in if the cage has over-rotated.

Mark B in Seattle

Thanks for the detailed info. I'm going to archive it for when I use a Soma cage on one of my projects.
Do the modifications work for the original (early 60's) GS, or for Nuovo Gran Sport?

I suspect the 13-17 was the sweet spot, being a 1-tooth corncob. I’m talking about the Campy Gran Sport, not the Shimano GS models. I’m personally not one who likes to escape the originals if I can try to get more out of it. If you can play with sprockets, you might try to go up to 13-14-15-18-21 (or even 13-14-16-19-22 or 23), which would get you about 23% more mechanical advantage than the 13-17. In this case you’ll almost certainly need to optimize chain length, adding links. Campy has really good guidelines for chain length for index-era, but I haven’t seen the equivalent for our true vintage stuff. Maybe Sloan’s book or Tom Cuthbertson’s book has some good directions.

I’ve sometimes found that the chain length or the wheel position can be changed to rotate the cage so the upper wheel is farther away from the largest cog. This early Campy design was made for the racing setups of the day (mid 1950’s, I think), which were rather close ratio. Even the 52-42 with 13-26, which we often think of as nice for the 1970s (NR era) but unacceptable today, are probably too wide-range for this derailleur. This is not the Nuovo Record or the original Record, which have an offset cage to accomplish this. I’m certain the NR can handle 13-26, but not much more than that. Some riders have had good results with 28 tooth big, but I have not. But at my age I need more modern assistances, anyway.

I replaced worn original, but un-cracked, Campy pulleys in a beater Super Record rder with basic Shimano replacement pulleys, and shifting improved noticeably.

I had bought 2pr of the the Shimano pulleys for maybe $12? Then discovered I can buy a 10-pair bag for $22-$28/bag. A nice 10pr bag is now on the way, so for less than $2.50/pr I'm set for a few years of pulley replacements. The Shimano pulleys are black, not Campy gray, and they have "SHIMANO" molded into the plastic, so they won't pass muster at your next Concours d'Elegance, but they do the job.
https://www.treefortbikes.com/Shiman...hoCtI8QAvD_BwE

Crikeys! I paid $24 for my bag, but Tree Fort has a price match for $19. Foiled again!

I mis-spoke when I said no versions of the GS fit the Soma cage without modification. I always forget about the aluminum Nuovo GS -- it has the same lower pivot bolt thread as a NR/SR, so the Soma cage bolts right on.

I was talking about the original steel and bronze GS, that went through several versions, but all of them need the Soma cage modified.

Here's a Nuovo Gran Sport that I "upgraded" years ago. That's a real Rally cage, not a Soma, but functionally about the same. (The Soma cage is longer, wraps more chain, but the Rally is plenty long enough for most C&V builds)
https://cimg9.ibsrv.net/gimg/bikefor...12cb73539b.jpg
This mech doesn't really have any reason to exist, being just an uglier version of a NR, but this one was built up to go on a Bianchi Gran Sport I was selling. Seemed like having a GS mech on a bike named GS made sense. The Bianchi came to me with a Sportman (not Sport) rear derailer, that's pretty rare, so I kept it for "the museum" (my junque pile).

Mark B

I am learning and have another concern. Are the jockey wheels on the Gran Sport worth using. I have a brand new set on my Rabeneick 120d ans they worked OK.
https://cimg4.ibsrv.net/gimg/bikefor...c5391c55fc.jpg

https://cimg6.ibsrv.net/gimg/bikefor...bdd9d0eb1b.jpg