I have been riding a 2006 specialized tricross comp with a 48/34 crankset, 35t/11t 9sp cassette and 25cc tires. Is it worth the cost to get a road bike or should I upgrade the front crank and cassette? I currently ride 175-250 miles per week and want to increase my spinning ability. I climb a lot of hills and average about 21mph on the flats. I am looking at a New 2006 scwinn fastback pro but have not ridden a lot of other road bikes yet. This has a 50/34 crankset and a 10sp 12/25 cassette(I think). Any input appreciated and I am on a fairly tight budget this would only set me back 1400$ Thanks.