Comment by Bedon292
15 days ago
I feel like perhaps this is a bit too nuanced of a critique. While I do see what you are saying on many images of bicycles, there are also many that that I do not see it on. Close to half of them, in a quick Google image search, have forks appear straight and the axle is dead center on the ends of them. If there is something there, I am not seeing it even when trying to specifically look for it.
I'll also note that, using a piece of paper as a straight edge against my screen, there is a very slight forward curve on the low and a bit more on the high responses. Medium does appear to be perfectly straight.
There are two things involved. What you are mentioning is the fork offset. Whether the wheel is mounted ahead of the steering axis. Either by the fork having a bend, or the mounting point of the wheel not being in the dead center of the fork. Note that this is measured in millimeters, and often not that visible in a picture. I'd say almost every bike except bmxes have it, but maybe not.
But even with zero offset, there is another thing in play. The steering axis is at an angle, a fork never points straight down. So even with zero offset, you still get a trail, which is the difference between the contact point of the wheel at the ground, and where the steering axis meets the ground. This trail is really what matters in the end, not how you get there.
See https://en.wikipedia.org/wiki/Bicycle_and_motorcycle_geometr...
But even better, play with (ctrl+f) "trail" in this simulation: https://ciechanow.ski/bicycle/
There you see the point. Even with zero offset, there is still a trail.