Have bike, will travel
Join Date: Feb 2006
Location: Lake Geneva, WI
Posts: 12,284
Bikes: Ridley Helium SLX, Canyon Endurance SL, De Rosa Professional, Eddy Merckx Corsa Extra, Schwinn Paramount (1 painted, 1 chrome), Peugeot PX10, Serotta Nova X, Simoncini Cyclocross Special, Raleigh Roker, Pedal Force CG2 and CX2
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Originally Posted by
Retro Grouch
15 is 27 (biggest cog) minus 12 (smallest cog).
The chain has to be long enough to safely cover the big/big combination. If it's too short, and you accidentally shift into that combination, the easiest thing is to bend the rear derailleur into your spokes. That can be real expensive and that's the only reason why I made a point of it.
For a customer bike, once the chain is long enough, I make sure the rear derailleur is able to take up all of the chain slack when in the little/little combination.
And that would be prudent and conservative but not a practical necessity.
Originally Posted by
Retro Grouch
For a personal bike I might "cheat" a little on that since I only use the granny chainring with the biggest 2 or 3 rear cogs. In other words, even though 41 > 38, the combination will almost surely work but I wouldn't send a customer bike out that way.
You should not have to "cheat" to get the result I recommend. Have you ever tried? Or do you just start a dispute anytime a result conflicts with your opinion?
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When I ride my bike I feel free and happy and strong. I'm liberated from the usual nonsense of day to day life. Solid, dependable, silent, my bike is my horse, my fighter jet, my island, my friend. Together we will conquer that hill and thereafter the world.
Last edited by Barrettscv; 10-11-12 at 12:39 PM.