Here is what I would do. Look on nashbar.com and see if you see a helmet you like. If you do note the price and then head to your nearest Performance bike to try it on if you can. If its one that fits, and if the price is cheaper at Nashbar Performance Bike will match it. Actually its a web presence for Performance bike so not sure if they are really the same company, but they do have a business relationship that will let them match the price.
IF the Performance bike isn't a viable option, measure your head and then call them to talk about fit. I wouldn't order till I could talk to them about fit and return policy. Helmet is usually something I would want to try on, but if your head isn't the size someone would typically carry that might not be an option.
A forum community dedicated to cycling and bike riders and enthusiasts. Come join the discussion about troubleshooting, maintenance, training, trails, racing, reviews, accessories, classifieds, and more!