People much bigger than you are enjoying the TW. What are the roads like on your commute? Is it city, country, highway? I ride to work everyday but it is only 4 miles of country road between 45-55 mph. If you need to go a long way on a busy highway everyday, I would get a bigger bike. There is really no reason you couldn't commute 70 miles a day on a TW though. A more comfortable seat or at least a seat pad may be in order.