Alex Rodriguez writes:

In article , says...
I have heard that using a tire with an aramid bead on an old non-hook
rim is a bad idea. Is this true? If so, could someone explain to me
how the aramid bead behaves differantly than a steel bead?
Also, what exactly is the purpose of the "hook?" Is this documented
somewhere?
A google search of the group only turns up some vague references to
not use kevlar beads on non hook rims, but no explanation.

Steel or non-steel bead, if the tire requires a hook bead rim, you should
use a hook bead rim. If you look at the tire closely you can see that
the bead has 'bump' on it that fits neatly under the hook on the rim. That
helps keep the tire on the rim under high pressure.

I just looked at the tires I have (pasela TG 27x1-1/4) and they don't
have that bump. They are smooth from the bead to the mold line which
sits just above the rim when mounted. Does this mean they are made
with hookless rims in mind?