Can anyone please explain why different manufacturers use either 1/24 and 1/25 scales. Is there an important reason for this difference?

Depends on who you talk to. As a young modeler in jr high in the mid 50's (I know that makes me old and/or irrelevant, but I don't care),we were scale snobs. 1/25 was THE scale, everything else was too small(1/32)or too big(1/24)not to mention some of it came from Europe(eeewww)

This not to start anything, it was just how it was.

It was my understanding that the original "promos" in the US were all 1/25 at the suggestion of the auto manufacturers so as not to confused with toys and that an adult male could have a model of his car on his desk.

In the late 50's a numbers AMT,Revell and JoHan started producing kits with more detail than the promos and started including "custom parts" to allow the young builders to create their own customs in scale mirroring the full size craze popular at the time.

Over the years the "bi-scale" thing seems to be less important to modelers and some build in both scales and (horrors) even mix parts. I think it's a personal preference about the scale or where the kit came from. With plastics companies trading molds and outsourcing where it comes from becomes a moot point.

Wiki has a nice article on scales etc, that has way more info than I care to type.

Hope this answer your question. This is just MHO on the subject.

Jake

Thanks John for your info. I'll also check out wiki