The depth of the rim determines how aerodynamic the tires are. But the difficulty is that the deeper the rim, the more the cross winds will push you around. The weight of the person riding the bike is also a key factor in determining the depth of the rim. The higher the weight the lower the measurement of the rim. The overall quality of the tire will also depend on the build quality. The weight of the person riding the bike is also a key factor. Therefore it is very important to and the rim quality. There are many companies online that sell these, but you have to make sure that these companies are going to be around later on to support you. It is important to not get taken in by cheap prices and going for a good brand that will support their product.easton ec90