crankset advice

  1. Rainbow Grease

    Crankset: 10 speed crank compatible with 9 speed Cassette?::

    HI: I want to upgrade my stock crankset with this SHIMANO 105: http://www.niagaracycle.com/product_info.php?products_id=405844 However it says is only compatible with 10 SPD chain, does this mean I also have to upgrade my 9SPD cassette to a 10 speed? Here is my current config...