It may not be a big weight difference but the Alu bike will feel faster and that's important. Now is the time to buy a cross frame before people start getting excited for the season. I'd do it and hold on to it or swap the parts from your volpe and build the volpe into a commuter.
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I'm not one for fawning over bicycles, but I do believe that our bikes communicate with us, and what this bike is saying is, "You're an idiot." BikeSnobNYC