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53/39 to compact conversion question

Old 04-27-05 | 08:06 PM
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53/39 to compact conversion question

I have been thinking about buying a compact for my Soloist. I just want it for my half-dozen trips up to the Blue Ridge Mountains each summer, and I am happy with the 53-39 almost all of the time around home. I already own a nice set of carbon cranks, and would prefer not to spend another $400 on a crank I will use 6 times per year, and I also don't want to put a piece of crap on one of the nicer bikes I own. My question is, is it possible to replace only the chainrings without replacing the entire crankset? It looks like the 50-34 might be pretty close in relation to the existing bolt pattern, so I'm not sure if it will fit. What do you guys think?

ps- Sorry if this has been covered. I searched and I wasn't able to come up with anything useful.
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Old 04-27-05 | 08:14 PM
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Probably won't work. The bolt circle diameter is too big to bolt a chainring smaller than 38 teeth onto.
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Old 04-27-05 | 08:32 PM
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Originally Posted by hoodlum
I have been thinking about buying a compact for my Soloist. I just want it for my half-dozen trips up to the Blue Ridge Mountains each summer, and I am happy with the 53-39 almost all of the time around home. I already own a nice set of carbon cranks, and would prefer not to spend another $400 on a crank I will use 6 times per year, and I also don't want to put a piece of crap on one of the nicer bikes I own. My question is, is it possible to replace only the chainrings without replacing the entire crankset? It looks like the 50-34 might be pretty close in relation to the existing bolt pattern, so I'm not sure if it will fit.
It won't. 38 is the smallest that can physically fit on a 130 mm BCD crank, and it's not worth the trouble for one measly tooth (2 1/2% difference from 39.)

It would be easier and cheaper to go to a bigger cassette (and a new chain.)

My "Century Special" 13-30 cassette is quite popular, and will almost certanly work with your existing derailers.

If you don't mind replacing the rear derailer, you could go for something bigger, such as one of my "Cyclotouriste" 1-34 or 14-34 cassettes.

See https://harriscyclery.com/9 for details.

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Old 04-27-05 | 08:34 PM
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Originally Posted by hoodlum
I have been thinking about buying a compact for my Soloist. I just want it for my half-dozen trips up to the Blue Ridge Mountains each summer, and I am happy with the 53-39 almost all of the time around home. I already own a nice set of carbon cranks, and would prefer not to spend another $400 on a crank I will use 6 times per year, and I also don't want to put a piece of crap on one of the nicer bikes I own.
For 6 times a year, I'd get over myself and get a nashbar compact and matching BB. Ritchey compacts can be had for well under $200 aren't cr@p and use the ultegra octalnk BB.Switching back and forth will require repositioning and readjusting the BB.
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Old 04-27-05 | 08:36 PM
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Oh my, I had no idea Sheldon "All The Answers" Brown frequented this forum.
Nice to meet you Sir.
Good info, and thanks.
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Old 04-27-05 | 08:44 PM
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Originally Posted by Sheldon Brown
It won't. 38 is the smallest that can physically fit on a 130 mm BCD crank, ....
chainrings.com has a 37 130BCD. I also saw a custom 36, made from a 36 110 that had had the holes redrilled. Was a bit lacking in material around the outer part of the bolt holes,but the guy was riding it....LOL
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Old 04-28-05 | 01:09 AM
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Sheldon Brown is THE ZEN MASTER GOD TO THE ZEN OF THE BIKE. HE IS THE BEST. I LOVE YOU SHELDON BROWN.
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Old 04-28-05 | 04:46 AM
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Thanks for all the input. I think I will just buy myself a set compact cranks. I really don't need all that much provocation to buy new bike stuff, and it gives me a good reason to work on the bike. I appreciate everyone's advice, but wow, Sheldon Brown! It's not every day you get your questions answered by a legend.
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