Campagnolo Triple - front chainring needs lower gears

[Mick F]

Good decision.
I would do the same.

[johnb]

DIY job from way back;



from here;

http://www.hetchins.org/504g.htm

nice bike, but not for riding down farm tracks....

cheers

Now that is evidence if any were needed of an absolute bike boffin. Brucey you are in pole position for the May 2012 white coat award with 531Colin and Mickf vying for second place.

Update. Just been on the juddering thread and I see Niggle is now in contention also.

[Mick F]

And Brucey has won for his Campag hub, Campag QR, Campag NR rear mech, and Campag dropout.
This is not to mention his Campag outer cable and his chrome rear triangle.

Maybe these aren't his?


Mind you, the chain isn't Campag.

[johnb]

No, not his.

Award is for the knowledge of such material not ownership.

[Brucey]

Vibrant Hetchins + campy mech mine? -nooo....

I do have an entire NR gruppo stashed away plus odd bits of SR, choice of LF and SF hubs, and a rather nice vintage Holdsworth with chrome campag ends to put it all on, too. But it ain't built up. It used to be my roadbike gruppo years ago....

I do, though, have various DIY'd derailleurs kicking about including ones not a million miles away from the one pictured.

I also have a design for one that has all the benefits of the duopar etc but without the slop-inducing extra pivots. I've been sitting on this for about twenty years....has it passed its time? Put it this way, if you were offered a NR style (medium-long cage) rear mech that performed like a modern one (or better) would it be of interest?

cheers

[aoxomoxoa]

A quick update...

I've fitted the 24T ring at the front, very straightforward as suggested. Changing between the new inner and the middle ring is fine, although changing up is slightly more awkward than it was when I had a 30T inner ring, and changing down requires a bit more care when pushing hard. The new set-up gives a noticeably lower gearing if the need arises, but when changing down from the middle to the inner I'm finding it helps to drop a couple of sprockets at the rear at the same time to avoid having to big a gap between the gears - if that makes sense.

Anyway, I now feel confident that I'll be able to go low enough on the really steep sections in the Pyrenees.

Thanks to one and all for the input.

[Whippet]

I hope you don’t mind me resurrecting an old thread: I’d like to lower the gearing on my 9 speed Campy triple. I see the inner is 74 BCD and middle and outer 135mm. I’d like to go: 26, 36, 46 chainrings ( so hopefully keeping the jump between them to just 10 teeth ). Inner and outer seem available, but I can’t seem to find a middle lower than 39T. Any advice appreciated thanks.

[tatanab]

I can’t seem to find a middle lower than 39T.

You will not, a 39 is the smallest that can fit the 135 PCD. I reckon a 39 is pushing it and the chain rides on the crank spider, so I prefer a 40. On my Record triple I used to use 50/40/24.

[Whippet]

Thanks, might just get a 26T inner then and see how it goes.

[De Sisti]

I run Campag on my bikes, but have Stonglight chainsets. With the Campag front mech I have the following front ratios
without any shifting problems:
50/34/26
48/34/26
46/34/24.

Campag 10s ergo levers 9 or 10s front/rear mechs and Shimano hubs with 9s cassettes.

[scottg]

soma-nuova-retro-derailleur-cage-plates-1.gif (17.12 KiB) Viewed 470 times

Campag triple cage plates for old timey mechs. NR,SR etc
The also have jockey wheels.
http://store.somafab.com/sonuredecapl.html

[Brucey]

I can’t seem to find a middle lower than 39T.

You will not, a 39 is the smallest that can fit the 135 PCD. I reckon a 39 is pushing it and the chain rides on the crank spider, so I prefer a 40. On my Record triple I used to use 50/40/24.

FWIW I think the shifting on and off the middle ring is better if it is a 39 or 40 than if it were a 36T.

cheers

[Whippet]

Cheers guys, I’ll let you know how I get on with the 26T inner and existing 40T middle.

[Whippet]

Time for an update on this.

As I have some hills looming in the near future I thought I’d finally get around to fitting the 26T inner to go with my 40/50 middle and outer. With my mid cage Racing T rear mech the chain is either going to be too loose or too tight at either extreme. If I was dumb enough to select big chain ring and biggest cassette sprocket something would break. Otherwise, it seems to shift from 40 to 26 pretty well on the workstand, bigger test coming up next week. I’ll probably change the big chainring from 50 to 48 at some point just to remove the risk of damage, although having rather uneven steps of 14 and 8 teeth might be annoying. In the future, I may just bite the bullet and move away from the restrictive 135 BCD and fit a more appropriate chain set with 26/36/46.

Thanks for the advice, I’ll let you know how it performs in the wild when I do a hilly Audax around the Isle of Man this week.

[Brucey]

FWIW with setups of this sort I don't trust myself not to select the big-big combination in moments of, erm, 'duress' so I always make the chain is long enough to allow this combination to be used. The chain may run slack on some of the small-small combinations, but these gears should not be used anyway, and (unlike a short chain) this doesn't automatically break stuff.

Campag stuff doesn't lend itself to particularly low/wide range gearing; if you proceed down this route you can end up ditching the campag chainset altogether, or perhaps converting it to an alpine double (super-compact double in modern parlance).

cheers