I spent a significant amount of time riding side by side with friends on flat terrain, and as someone who pays close attention to power data, I feel confident that this bike doesn't come with an aero penalty. Based on what I've read about aerodynamics, the downtube is positioned in the 'dirty air' created by the front wheel, so having a slightly less aerodynamic shape doesn’t significantly impact performance.

I would also add that the biggest impact on aerodynamics comes from the cyclist and their position on the bike. However, it's true that I was looking for a stiff and lightweight frame, easy to handle on climbs. That said, with this bike, I’ve improved many of my personal records, even on flat terrain.

I love the Swiss flag

Do you have other road bike for comparison purposes? On the fence between this and SC-R55...

I own a 2018 BMC Roadmachine size 54 and a 2011 Kuota Karma. There is no comparison with the Kuota, whereas compared to the BMC, I can say that, in terms of ride quality, I haven't noticed any significant differences. In fact, I actually prefer the LCR017 because I built it to fit my measurements. The geometry has a slightly longer reach and a lower stack. Surprisingly, I feel more comfortable with the lower stack, which is about 3 cm lower. As for the reach, I compensated by shortening the stem.

The frame I received is of excellent quality, and the assembly went smoothly. The BB on the LCR017 is a T47-68 mm, which threads into the frame and is easy to handle, whereas the BB on the frame you're proposing is a press-fit type, which is a bit trickier to deal with.

I wouldn’t underestimate the issue with the rear hanger. If you do races and need to change wheels quickly, I think it's better to avoid the LC frame. Otherwise, the issue is almost negligible, though personally, it does bother me a bit.