Trust me, I geared down sufficiently, I was running 34 X 21.
When you hit around 155mm and below in crank length pretty much any normal riding becomes difficult as there isn't enough torque.
For a specific purpose, such as polo/pedal strike related issues, I fully recommend it.
However the OP stated that he was considering it as a way of getting rid of knee pain, in this case I think he'll find that he's wasted a lot of money buying 145 cranks, not getting on with them and having virtually no chance of re-selling them.
Trust me, I geared down sufficiently, I was running 34 X 21.
When you hit around 155mm and below in crank length pretty much any normal riding becomes difficult as there isn't enough torque.
For a specific purpose, such as polo/pedal strike related issues, I fully recommend it.
However the OP stated that he was considering it as a way of getting rid of knee pain, in this case I think he'll find that he's wasted a lot of money buying 145 cranks, not getting on with them and having virtually no chance of re-selling them.