# double or compact front sprokets/crank size



## Bizman (Apr 27, 2011)

Is there a "norm" that most of you follow for the front sprokets and front crank length on the Bianchi, double 54/39 or compact 50/34? I am working up the build on this Infinito and just not sure what may be best? 

The Ultegra version I test rode had the 50/34 and it seemed to spin up real nice, although not sure what the crank length was but assume 175mm?


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## Bizman (Apr 27, 2011)

I gave my proposed build to the LBS today. He said for our area the compact 50/34 would be the way to go as we have a lot of hils. I asked about the crank length and he thought 170 because its a 53 and thats the same I run on my mountainbike (Tallboy)


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## kbwh (May 28, 2010)

Yes.
Chainwheel sprockets should be chosen based on rider ability and terrain. Most recreational riders are just fine with a 50/36 for flattish and 50/34 for hillier terrain.
Crank arm length is mainly a function of leg length. 170 for a 53 frame is roughly ballpark. Here's a reference: http://www.cptips.com/crnklth.htm


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## Bizman (Apr 27, 2011)

If I go with the chart, I am in the 170mm crank range for "size of bike and inseam". I use a 170 mm crank on my med mountain bike, it seems to spin up good (for me)


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