bent eagle

Since I'm interested in upgrading to a nicer road bike, and also experience some issues with back pain, I wanted to try to find a way to quantify the geometry differences between some popular plush bikes.

After looking at the geometry numbers from several models, I came up with the following method of comparison, from the point of view of someone looking for a more upright riding position. I decided to calculate the ratio of head tube length to effective (horizontal) top tube length.

My rationale was that, while any bike can be somewhat customized with different stems and spacers, the starting point in terms of frame geometry would be fixed, and therefore an important basis for comparison. The idea is that a bike can place the rider into more of an upright position either by raising the head tube, shortening the top tube, or some combination of both.

Here are the results, sorted by ratio, starting with the most upright position. I used my frame size (58) in all cases, so I'm not sure if the ranking would match in other sizes.

Specialized Roubaix - .3866
Jamis Endura - .3621
Giant Defy Advanced - .3565
Cervelo RS - .3448
Cannondale Synapse - .3448

Obviously, if you want a plush bike with a less upright riding position, you might want to start at the bottom of this list and work your way up. Note that the Synapse and the RS are the least upright, and have exactly the same ratio.

Hope this helps somebody who is considering one of these bikes. If anybody wants to add to the list, feel free. I just took the closest size to a 58, and divided the head tube by the top tube (effective).