Stap, When I bought my Klein it came with a Standard road crank and a 12x23 rear cassette. I was so impressed with all the Dura Ace stuff on the bike I didn't want to change anything. The cassette was even a Dura Ace. I headed to a local little 13 percent hill about 3/4 mile long. Just before the bottom of the climb I shifted into 38x12 spun as fast as I could go and attacked. I didn't get 300 feet before I was in 38x23. I got to the top of the hill and almost fell off of the bike sucking air so hard I was afraid I would suck gravel off of the ground. I still have the cassette but it isn't mounted to any wheel set.