Gearing with compact crank?



hjbiker43

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Aug 14, 2006
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I'll be installing my new compact crank (Ritchey WCS 50/34) here shortly. I presently have an Ultegra 9spd drive train with a 12-27 cassette. I'm just wondering if a 12-25 would be better reference big jumps when changing gears. However, I do live in the mountains so the lowest gearing would really be helpful! I know, a triple crank is an option, but I thought I'd give the compact system a try first. Any suggestions would be appreciated.
 

gclark8

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Apr 13, 2004
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Stay with a triple, however, plug both sets of gearing in here and print them out for a direct comparison: http://sheldonbrown.com/gears/

I live in flat country and fitted a 13-23 to the Felt, sometimes I do find the 42tooth a bit high, a 39t would be better.
 

ozelise

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Aug 12, 2005
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Why go with a triple ? Save some weight, go compact 50/34 and leave the 12/27 cassette. Virtually same ratios as triple with 12/23, but lighter and better chain line.
 

bobbyOCR

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Aug 31, 2005
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ozelise said:
Why go with a triple ? Save some weight, go compact 50/34 and leave the 12/27 cassette. Virtually same ratios as triple with 12/23, but lighter and better chain line.
Agreed. 34-27 should be low enough for anyone. I have a 39-27 and only use it up very steep climbs (River road, anyone from WA) But there are no real mountains here. I say get a SRAM Force or Rival 11-26 cassette from ebay. Then you have a very low gear and a very high one. (BTW, the SRAM cassette does improve shifting and makes it a hell of a lot quieter)
 

fitz

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Oct 10, 2005
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I use a 50/34 with 12-25 campag set-up. Gets me up most things in the high country with a bit of style. No - gets me up everything. In my mid 40s with average cycle fitness, its great. But if the fan collided with the excrement its always possible to change the front lower to a 34. If you cant work with this maybe you should take up diving!
 

fitz

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Oct 10, 2005
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fitz said:
I use a 50/34 with 12-25 campag set-up. Gets me up most things in the high country with a bit of style. No - gets me up everything. In my mid 40s with average cycle fitness, its great. But if the fan collided with the excrement its always possible to change the front lower to a 34. If you cant work with this maybe you should take up diving!
make that a 50/36. with the option to go to 34
 

dhk2

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Aug 8, 2006
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hjbiker43 said:
I'll be installing my new compact crank (Ritchey WCS 50/34) here shortly. I presently have an Ultegra 9spd drive train with a 12-27 cassette. I'm just wondering if a 12-25 would be better reference big jumps when changing gears. However, I do live in the mountains so the lowest gearing would really be helpful! I know, a triple crank is an option, but I thought I'd give the compact system a try first. Any suggestions would be appreciated.
The compact is a good way to get lower gears on an existing bike. I'd stay with the 12-27 for now; you can always change when it's worn out if you find you never use the 27. If you routinely climb seated at 5-6 mph, bet you'll want the bottom gear.

A buddy of mine just got a new bike with compact gearing (34/23 low), and he now actually wants to climb 15% grades he's always avoided. I'm trying to teach him that he doesn't need to jump out of the saddle now, that he can use gears and not make every steep grade a life-or-death attempt to break the stem off the bike.

The question for me isn't whether you can "make it up the hill" in a macho gear, but what gearing will give me the best finish time on the mountain challenge centuries.
 

Bob Ross

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Jun 22, 2006
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I've got a 50/34 up front with a 12-27 in back.

Regarding jumps between gears: in the smaller cogs where it seems to matter most, they're all 1 tooth increments. Where those become 2 tooth increments is right about the point where you're starting to think "er, ****, gotta get up this rise" at which point it seems to me that the arguement for jump-less shifting is moot.

(Or were you talking about jumps when shifting between the front chainrings?)

As for climbing in a compact versus a triple: I'm 45, only been riding "seriously" since March of this year, and there's almost no hill I've come upon that I can't get up with this compact. In fact, I've only had to get in my lowest 34+27 combination twice. The only time I've ever wished I had easier gears than that was (perhaps ironically) yesterday, when, 15 minutes after doing a 3 mile sprint at >30mph, I came upon a 0.8 mile section of 9.9% grade. I managed to putter up it at 5 or 6mph, and I'm pretty confident I could take that hill much quicker if I hadn't blown my legs out in the sprint, but yesterday I found myself wishing I still had the old hybrid with the 22 tooth granny gear up front!
 

gclark8

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Apr 13, 2004
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I suggest the compact crank (50/34) and wide range cassette (12-27) has an echo of MTB gearing without the inner chainring.

Many Perth riders have tried compact and gone back to "normal" to loose the large jumps between the gears. Personally, below 21t, I will not ride with more than a 1 tooth jump, and above 21t a 2 tooth jump, it drops the cadence too much. :)
 

ksalzberg

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Mar 24, 2006
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I got a compact for the first time this spring - in preparation for a trip to the Pyranees. Got a 50-34, and 13-29. While I didn't end up using my new bike overseas, the bike I rented had a low of 30-25, which is very close to the low I've got (34-29). If I were spending a lot of time climbing long steep climbs (in the Pyranees, or Alps, or Rockies), I'd be quite happy with my present setup. The low is low enough, and the high is high enough.
However, next spring I'm going to get a 12-25 or an 11-23, to get closer ratios for my normal riding - which is not, malheureusement, in the Alps.
 

fitz

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Oct 10, 2005
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gclark8 said:
I suggest the compact crank (50/34) and wide range cassette (12-27) has an echo of MTB gearing without the inner chainring.

Many Perth riders have tried compact and gone back to "normal" to loose the large jumps between the gears. Personally, below 21t, I will not ride with more than a 1 tooth jump, and above 21t a 2 tooth jump, it drops the cadence too much. :)
Im sure many Perth riders have - but the climbing here in victoria is a little different to say the least and it is here a compact comes into its own. I find it a slight pain on the flat days and use a 50/36 with 11-23 and in the hills 12-25. Ive never wished for anything bigger than 50 12 either even on the fastest decents
 

hjbiker43

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Aug 14, 2006
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Thanks for all of your responses. Very useful advice. I will try the 12-27 in the rear with the option of going to a 12-25. I'm really looking forward to tackling some of the climbs around here with this set up. Should be a good test! Thanks again.