It's the diameter of the handlebars that's different. Width wise, both measure same. My first road bike has a wider diameter handlebar, the second road bike the diameter is noticeably smaller. I'm almost paranoid about injuring my neck again. I was off work for weeks last spring and ended up with months of PT and massage therapy. I was pretty miserable and just felt like it was never going to heal. I still have the occasional tingling down my left arm. All caused by me riding an ill fitted bike and telling myself I just needed to get used to my new bike....Never again! I learned the hard way to be way more assertive during a bike fitting.