Bike geometry charts can be fairly simple to understand but sometimes difficult to compare. It’s not uncommon for two bikes to have similar geometries but for the feel to be completely different from one bike to another.
To help consumers better compare the geometries of bikes in the same category, many manufacturers now publish the measurements commonly referred to as stack (frame stack height) and reach (frame reach).
Although these measurements have long been used in the triathlon world, their widespread use began in 2008, when some mountain bike companies started publishing this information. The goal of these measurements was to establish a new industry standard to allow comparisons between bikes from different manufacturers. It should be noted, however, that while frame stack and reach can help with comparisons, you still need to look at the bike’s overall geometry to get the full picture.
The basic idea behind these measurements is that the top tube length, a commonly used measurement for road bikes, does not give a real indication of how the bike will feel once you’re positioned on it. To provide a more accurate basis for comparison, manufacturers instead use the relationship between the pedals and the handlebar, and use frame stack and reach as measurements to explain this relationship. The latter is the horizontal distance between the center of the bottom bracket and the top of the head tube, while stack is the vertical distance between the center of the bottom bracket and the top of the head tube. By looking at a bike’s measurements, you can now get a much clearer idea of your position on another bike.
Comparing a few popular Scott and Devinci road models, we see that these two manufacturers use different approaches. You’ll feel a clearly different fit between the various Scott road models, for example, as the performance-oriented Addict is 0.3 inches (7.7 mm) longer than the more comfort-focused Solace. That may not sound like much, but since we’re talking about two bikes of the same size, the difference is obvious as soon as you sit on them. Devinci, on the other hand, generally offers the same position on its two carbon road models, the Leo SL and the Leo.
| Medium men’s bikes (mm) | Scott Addict | Scott Solace | Scott CR1 | Devinci Léo SL | Devinci Léo |
| Frame reach | 388 | 381 | 384 | 381 | 381 |
| Frame stack height | 549 | 572 | 564 | 556 | 556 |
If you have any questions or comments about bike sizing, don’t hesitate to send us a question!
