Mohamed,

Thanks for this!

I would prefer to use an override but am not sure the path. Does this look right?
/templates/TEMPLATENAME/html/mod_k2_tools/helper.php

AND

This code works for some but not all the catTitle.
example of site under construction

Try to decrease the value of $catTitleLimit

I have but that would not make sense.

If the first 2 sub-categories were truncated why was the last not?

The no-wrap attribute of .catlistmenu .catTitle causes this. But you have to specify a smaller limit as well.

PS. you can do the same with CSS as well.

text-overflow: ellipsis will do the trick.

text-overflow: ellipsis was the answer!