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· No Crybabies
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Discussion Starter · #1 ·
I have lots of chainrings and just about every cassette for Campy 10 speed possible, so I thought I would experiment, especially since we have big, steep climbs (and descents) around here, and a very wide gear range is useful.

The SRM/FSA crankset came with 2 sets of rings, 50/34 and 53/38. So, on a whim, I threw on the 53 and the 34, and combined this with my custom 11-29 cogs, 11, 12, 13, 15, 17, 19, 21, 23, 26, 29. This is with a newer Record short cage rear derailleur and a Record front derailleur designed for compact crankset, shifted with Record Ergopower.

You get the following gear inches, but I would avoid the * ones:

53 34
11 128.2 82.2*
12 117.5 75.4*
13 108.4 69.6
15 94.0 60.3
17 82.9 53.2
19 74.2 47.6
21 67.1 43.1
23 61.3 39.3
26 54.2* 34.8
29 48.6* 31.2

That gives the following meaningful gear inches, rounded:

31, 35, 39, 43, 48, 53, 60, 61, 67, 70, 74, 83, 94, 108, 118, 128.

It works amazing well. The front shifts as well as any set up I've ever had. The only limitation is that in the 34x11 combo, which you would not want to do anyway, the chain rubs the big ring and can catch on the shifting pins. The low gear is also lower than a 30x25 triple low gear.

The rear works perfectly fine, too, with the one serious limitation that you cannot shift to the big/big, 53x29 combo. It is not foolproof, because if you do that, you could do some serious derailleur damage. But, as long as you avoid that, the whole thing works as well as any system I've used.

Many might question giving up the 14 and 16. Doing so creates about a 10 rpm jump between gears, which to me is about right for everything except a flatter, short time trial. Sure, in a time trial I'd like to have 5 rpms or less between gears, and I do have that on my TT bike, but that's not what this is for. This is for going up and down mountains, typically the kind of ride where you are climbing or descending for 5 miles or more at a time.

Anyway, for those looking for an option for a very large range, but not a triple, this may work for you. It shouldn't work, but I can say from experience that it does. Rode 75 miles with 8,000 feet climbing, with 18% grades, on it yesterday.
 

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thoughts...

Of course you need a medium cage RD, then you'd have plenty of wrap capacity.

When I tried making a 12-29 with the 12-15 from a 12-25 and the 17-29 from my 13-25, the 15-17 shift was lousy.

Do you know the specific cog letter designation that you have at the 15-17?
 

· No Crybabies
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11,692 Posts
Discussion Starter · #3 · (Edited)
cogs

C-40 said:
Of course you need a medium cage RD, then you'd have plenty of wrap capacity.

When I tried making a 12-29 with the 12-15 from a 12-25 and the 17-29 from my 13-25, the 15-17 shift was lousy.

Do you know the specific cog letter designation that you have at the 15-17?
I used the bottom half of an 11-25 and the top half (6, joined in pairs) from a 13-29. I think these were both Chorus (all steel) cassettes. I've given up on Ti for the most part, with premature wear issues, especially with the cost of them these days. I save them for racing only. My confidence level that this is precisely what I'm using is only about 80%, as I have about 10 Campy cassettes, and some may have gotten mixed up.

I suppose what is critical is the spacer between the 15 and 17. Not sure which one I used, but it works. As you know, there are about 5 or 6 different spacers Campy uses in its cogsets, and some are very similar but not quite the same. Might try to experiment.


Added: I'll check the specific cogs and spacers and let you know.
 

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Discussion Starter · #5 ·
minor

FatTireFred said:
how bad? is it a minor annoyance or recipe for chainsuck?
No suck at all. Just a little noise and a little hiccup now and then. Nonetheless, I shift right away.
 

· duh...
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Fixed said:
No suck at all. Just a little noise and a little hiccup now and then. Nonetheless, I shift right away.


how long are the chainstays on your bike? I imagine it could be worse w/shorter, or perhaps 'better' w/longer
 

· No Crybabies
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11,692 Posts
Discussion Starter · #7 ·
short

FatTireFred said:
how long are the chainstays on your bike? I imagine it could be worse w/shorter, or perhaps 'better' w/longer
It's 55 cm Bianchi 928 SL racing bike. About as short as it gets.
 
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