Something else to consider: At 32 lbs you are close to the load capacity of an aluminum rack, assuming that you are using the stock rack that came on Miyatas. One of the biggest differences that I found on my touring bike was going from an aluminum rack to a steel Tubus. It's stiffer and less prone to flexing. On my tour down the Columbia River (see Picking the Scablands), I was amazed to watch the aluminum rack on my daughter's bike sway back and forth under the load as she pedaled. It was bad enough that we swapped out the old rack at some point for a better (but still aluminum) rack.

They are worth the investment.