Have you been professionally fitted to the bike? If not, I would seriously consider it. Numbness in the hands can be caused by a variety of things - usually fit and fitness related. If the bike fits, then it could be a matter of conditioning. Your midsection handles a lot of the weight balancing and if it's not strong enough, the excess will go to the hands. Next time out after you've confirmed bike fit, consciously think about supporting your body through the middle while keeping the elbows slightly bent and the hands relaxed.

The good news is the numbness should subside as you put in more miles and get stronger.

55/Rad