About what year did the rib front tires disappear?

Jimmy, I'm gonna make a guess at mid 70's, maybe a bit earlier, really hasn't been all that long ago, course when your my age, things are never what you think they are, or where they are, they say God does that, just to keep you moving around, so ya don't get fat, or lose your memory, and I don't need any more "fast" time, gimme what we used to have! You doin OK, hope to see your sorry butt this summer! Bob

I'm doing good Bob. Just tired of winter. Seems like the ribs just disappeared and it all something different. Your right, had to be middle 70's.