Well they both have Tange Prestige Concept mainframes, and I don’t think Tange changed Concept during its production lifetime, but there are a few differences. The most important of which of course is that only one of them has Explosif decals. Let’s face it, it is quite a good name for a bike.
Explosifs were usually made to a slightly higher specification than Kilaueas. For example the 93 Kilauea had the same stays as the Cinder Cone, whereas the Explosif had Concept stays (and your 91 Explosif may have Concept stays as well, but I don’t know). On the other hand, they improved the designs over the years, e.g., 1992 was the first year they said the Project Two was triple-butted, so I’d guess (I’ve never ridden a 91 Kona) that the 91 P2 may be slightly less sophisticated. So a 93 Kilauea could be pretty much equivalent in quality to a 91 Explosif overall.
The geometry was quite different between those two years. The 93 frames were smaller, with shorter top tubes and head tubes, as they began to accommodate the changes needed to suit the first suspension forks. 1993 was the transition year towards 1994, which established Kona hardtail geometry. They have never changed the geometry since 1994, which I think was the geometry that Joe Murray left them. Maybe one day they’ll get over him leaving them, but not quite yet you might think.
