Compact crankset with NR groupset

[cgolvin]

Revisiting a previous thread now that I've got everything assembled.
Background: replaced my standard NR crankset with a compact Veloce (concession to steep climbs on Eroica).
Freewheel is a 7 speed 13-28.
Chain is KMC 9-speed.
Looking for insight on both derailleurs. I've only tested it on the stand, will try to take it out for a shakedown ride later this week.

I finally put the chain on yesterday and did fine tuning on derailleurs. Using OP's trusty small-small chain length guidance, on my first try there was not enough clearance between the upper pulley and the 28, though all other combinations seemed good. Since I'm looking for low end that wasn't acceptable so I took out one more link. It's now good in the 34-28 but clearly too short for the 50-28…that's ok, wouldn't use that anyway but I need to remember not to.

The front will shift up to the 50 but only at the very end of the shifter's range and that shift is not very smooth. I suspect I will have to shift somewhat gingerly. The derailleur is mounted with the bare minimum of clearance for the big ring and in the 34-13 the chain rubs slightly along the back of the derailleur. Again, don't need that combo and it's a good reminder to just avoid both cross-chain combinations. My guess is that a 16 tooth gap is at the extreme end of what the NR FD is able to do so I should be happy that it works with these limitations.

Interested in any feedback, especially from anyone who has been able to make this configuration work better than I've described my setup. Thanks.

[stien]

Here's an exhaustive thread on the classic and vintage forum about this very topic:

https://www.bikeforums.net/classic-v...roblems-2.html

I love those guys.

I seemed to recall that there was no b-screw on the NR RD, you only have chain length, spacers behind freewheels, and horizontal dropouts to play with.

I would certainly account for being able to shift into the big-big without destroying things.

As for the front, you mention that it's at the end of the shifter range, is there enough cable slack to take some up so it shifts earlier in the lever range?

[cgolvin]

Originally Posted by stien

Here's an exhaustive thread on the classic and vintage forum about this very topic

I seemed to recall that there was no b-screw on the NR RD, you only have chain length, spacers behind freewheels, and horizontal dropouts to play with.

Thanks; though with the exception of one comment on using a triple they all seem to be using a standard (52/42) crankset.
My wheel is already as far back into the dropouts as possible (should have mentioned that, sorry).

Originally Posted by stien

I would certainly account for being able to shift into the big-big without destroying things.

As for the front, you mention that it's at the end of the shifter range, is there enough cable slack to take some up so it shifts earlier in the lever range?

At this point, I'll trade off being able to use the 34-28 with remembering to avoid 50-28.

There's no slack in the front cable at all.

[stien]

Roger that. Is there enough gap between the 13 and the dropout to try a spacer behind the cluster?

[cgolvin]

Originally Posted by stien

Roger that. Is there enough gap between the 13 and the dropout to try a spacer behind the cluster?

Doubt it — I guess I could try to find a 6 speed with a 28, but given that Eroica is 13 days away I don't relish the thought of changing the freewheel.

[stien]

You could always try throwing a washer on the RD mounting bolt.

[David Benson]

Ive successfully run Nuovo Record deraillers with 47/34 TA cranks, and also Zeus 49/36.
Its easier with the long 1010 dropouts that allow you to slide the wheel back behind and away from the derailler.

50/34 with 13-28 is a few teeth more than the capacity of the derailler. Rather than risking disaster in the event you accidentally shift ino 50x28, I suggest letting the chain run slack in 34x13.

This is on the Masi with 49/36 rings that I rode at Eroica last year. Sorry for the extra-low fidelity.

[cgolvin]

Originally Posted by David Benson

Rather than risking disaster in the event you accidentally shift ino 50x28, I suggest letting the chain run slack in 34x13.

Thanks. But based on my first try, I think slack in 34x13 would bring the upper pulley back into contact with the cog in 34x28.

[sg8357]

You need a vintage solution,

https://store.somafab.com/sonuredecapl.html

Long cage for the NR derailleur, note this gives you front ring range,
not big cogs in back. 13-25 in back 46/32 in front using a Stronglight 49a
and VeloOrange copy.

[mtechnica]

I put an IRD defiant on my girlfriends super record equipped bike and have this exact problem. She likes the big ring so I have it set up to go loose in the small smalls, but I think it could be better - glad there’s some ideas in here.

[David Benson]

Originally Posted by cgolvin

Thanks. But based on my first try, I think slack in 34x13 would bring the upper pulley back into contact with the cog in 34x28.

Can you move the wheel back further in the dropout?
I understand that youve posted about this previously but it might help if you could reiterate what frame you have, and what dropouts.

[cgolvin]

Originally Posted by David Benson

Can you move the wheel back further in the dropout?
I understand that youve posted about this previously but it might help if you could reiterate what frame you have, and what dropouts.

It's buried earlier in the thread, but the wheel is already as far back as it will go.

It's a 1978 Gios Super Record with Campy dropouts: https://forums.thepaceline.net/showthread.php?t=196689

[stien]

I’ll reiterate the washer on the mounting bolt suggestion. If the upper pulley does indeed follow a non-straight path across the cogs towards the largest, it might buy you the clearance you need.

It also goes without saying that you oughta check your rd hanger with an alignment tool.

[muz]

I think your easiest path is to use a different crankset, e.g. a vintage TA using smaller rings, like 40-28. You will not need a taller gear than 40/13 unless you are racing it; just tuck and coast.

[choke]

I have one bike with a 35/48 Victory crank and a 13-28 rear with NR derailleurs. I can shift to every combo but it's pretty tight in the 48/28.

As for the front derailleur, another bike has a 30/46 TA crank and a 13-28 rear with a NR FD and a Rally RD. The FD shifts that 16 tooth difference just fine and obviously the extra length on the RD cage means there's no problem at the back.

I'd agree that probably the best solution is to put a Soma cage on the RD.