Our tandem rides like a dream and fits me like the proverbial glove. But, certain road conditions cause my hands to go numb. I'm light in the handlebars, keep pressure off the various nerves, etc. I was blaming it on a resonant frequency in my CF fork, but I find that there is no buzz closer to the stem. It's got to be the Bontrager Al bars acting as a bit of a tuning fork. Short of buying CF handlebars which should offer more damping what are my options? Fill the hollow handlebars with expanding foam? Other?