I'm thinking about changing from the SRAM PG950 12-26T cassette to one that is 11-34T (brand or model not picked yet). The thing is that I find the 11-34 cassettes in the MTB sections of catalogs, not the road bike sections. Would there be any problems replacing my 12-26 cassette with an 11-34? I live in a fairly hilly/mountainous area and could use a lower end. I don't want to go to a triple crank. Oh, and any recommendations on brand/model number of cassette would be much appreciated. Thanks!