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I am getting a new bike and don't know how to compare the Shimano Compact Crank with a Triple. I have been told that they are very close and the the main difference is the compact reduces the gear overlap. I currently have a triple and need the granny on some mountains in colorado or when I am really tired. If someone could help me out with some information on this decision I would appreciate it.
 

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This topic has been discussed a lot. The choice depends on the gearing range you find most critical. I prefer a Campy triple for the Colorado mountains, because I don't lose any top gear for the descents and I get about 2-cogs worth of additional low ratios with the triple. Here's a link to a recent triple discussion.

http://forums.roadbikereview.com/showthread.php?t=53686&highlight=campy+triple

A 50/34 takes 6% from the top gear ratio and increases the low by 13%, for a net increase in range of 7%, which is slightly less than an average 8-9% 1-cog change. In other words, you can get the range of 11 cogs with 10, but NOT without some expense. The reduced overlap that you mentioned causes more cog shifting after every chainring shift. Most often, it requires one additional cog shift to maintain a uniform gearing progression, compared to a 53/39.

I use equivalent gears to compare gearing. With a shimano 50/34 compact the lowest gear would be a 34/27 (assuming a 12-27 cassette). This gear ratio is nearly identical to a 30/24, the next to lowest ratio on a shimano triple, so this standard triple only adds one additional lower ratio, the 30/27. It also has 4% or half-a-cog more top gear.
 
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