Tom,
It's highly unlikely that bumps or even potholes are going to cause 1/4" (6mm) thick dropouts to get misaligned. Most likely they came that way from the factory. I've found very few frames with properly aligned dropouts, even from some of the most prestigious marques.
The fork and front axle form a triangle which is an extremely strong shape. The rear "triangle" is composed of multiple triangles.
Dropout alignment unless they are really far out has more effect on wheel bearings and axles than handling. Misaligned dropouts especially in the rear can result in bent or broken rear axles and premature bearing wear over time.
Chas. Colerich Oakland, CA USA
Tom Sanders wrote:
> Dmitry Yaitskov asked about what sort out of the ordinary tools members had
> found useful.
>
> I found that for a sort of an unusual tool, I got a lot of mileage out of a
> set of dropout alignment tools. Nearly all of my bikes were just a touch
> off. My hunch is that every bump into anything or pothole may move the
> dropouts a bit (Is this true? ) It's just a hunch on my part. I think 12
> out of 14 bikes I checked could have used a tweak. I frankly noticed no
> difference in riding them, however. Maybe I was just fascinated to have
> the tools like a kid with a new toy. Good lord! I see a set of them just
> went through E-Bay for $128! I sold mine for about half that. Ah well,
> somebody is enjoying them.
>
> Tom Sanders
>
> Lansing, MI USA