Shims are rubber triangle thingys that they put in where the silver part of the brakes meet the hood.

The kind of brakes the bike has aren't suppose to be able to use the standard shims. But when I told my bike shop I was having trouble, one of the mechanics said to put in shims. Another mechanic said - you can't use them on those. You need this other kind of brake to use them. My guy rolled his eyes and said they can shaped and they'll work just fine. So he shaped them a tad and put 'em in. It took about 3 minutes. lol It cost me $5.

However they work it out for you, I hope it works well. Brakes are good things.

I'm excited for you. Getting a new bike is wonderful.