They do have the teeth on the outer ring , the pawls and springy bits sit in the middle. ok, blind conjecture time... I figure they're most likely to increase the engagement by adding offset pawls rather than trying to fit extra tooth thingies in. If you only relied on 2 pawls engaging at once you could do it easy - You could probably convert an eno to 108ep if you indulged in a bit of jiggery pokery with a grinder. edit: Ah yes, if you read the thread properly you can see that hobnobs already figured that out