Originally Posted by
mack_turtle
sorry, but what does COA mean? not familiar with that term as it relates to bicycles.
I am not sure whether it's preferable to use a longer or shorter stem, or if at what point it matters. how short is too short for handling on a road-going bike? too long? that might be a bit subjective. it's also possible that a stem length outside of the norm on a conventional road bike is an indication that the rider chose a bike of the wrong size. in my case, I think I could make either of these bikes fit with a 70-100mm stem because the two sizes are not dramatically different.
The ETT on the longer bike is closer to what I have now, but the stack is a lot higher. either one could fit me. the larger one has less standover, but could offer a smoother ride and more room for bottle cages and stuff inside the main triangle. in the end, handling is more important to me. what handling characteristics should I expect from a smaller frame with a longer, higher stem, versus a big bike with shorter, lower stem? the BB, saddle, and handlebar will end up in the same position on each bike, but one will have a longer wheelbase.
Standover doesn't matter. I can't stand over any 29 inch wheeled mountain bike ever made without soft contact due to the sloping top tubes, even on a 15 inch frame. 17-18 inch mountain frames are what fit me, 54-56 road. I am 5'8" with a 32 inch inseam for reference. 20 years ago we thought smaller frames handled better, but the trend has steadily changed to longer top tubes and shorter stems. Longer stem isn't a big deal on the road, but it puts your weight further forward towards the front axle, and that can bite you on trails. 5mm stack height is not a lot of difference.