Hey Monty,
Can you describe the differences between these cranks would make in a 3 port or 5 port - 15007T, 15009T and your 15009HT
Next question for you is what size is the rear bearing in the N21BF? 25,4 or 25,8 - I am guessing the 25,8 but there is not an exploded parts page any where for reference
Thanks!!