I own a cannondale synapse 54 and a felt z4 in 56. The felt i believe is closer to 55 in actual geometry. I like my felt fit so much better than the cannondale for comfort. Iv been swapping stems ect to get the cannondale right. still no success. couldnt be happier with the felt .
Originally Posted by
tahoeeddie
I didn't go and compare all of the geos on the bikes you listed, but very minor differences in measurements are noticeable to a rider. the materials for the build will also be noticeable. that's why you really need to go out and test ride a bike before you buy it, IMHO. I bought a bike last summer, and rode 18 different bikes that had the same base size, but slightly different geos, and they all rode differently. It's not just about the sizing though, the stiffness in the BB, the components, all of that contributes to a unique ride.
When going between levels of components, usually you'll be getting better precision and lighter weight. When you get into the upper reaches of the product lines, you may sacrifice some durability for performance. But between 105 and Tiagra, I wouldn't worry too much.