When to accelerate?

[Double C]

My backswing is slightly below my shoulder at the top. As I'm moving forward, I let gravity swing the ball down. I try to accelerate at the bottom of the swing. Is this correct? It's not massive. Sometimes it works...sometimes it doesn't.
Sometimes I just let it swing naturally, and feel like the ball hits the pins harder.

[RobLV1]

My backswing is slightly below my shoulder at the top. As I'm moving forward, I let gravity swing the ball down. I try to accelerate at the bottom of the swing. Is this correct? It's not massive. Sometimes it works...sometimes it doesn't.
Sometimes I just let it swing naturally, and feel like the ball hits the pins harder.

With modern bowling balls, less is more. Just let gravity do it's thing, and watch the ball do what it is designed to do: knock down all the pins with very little help from you other than getting it on line and letting it roll.

[Blomer]

It's all about being consistent. Sometimes it works, sometimes it doesn't isn't consistent. As mentioned, let the ball work for you. Don't work the ball.

[LOUVIT]

I have tried to raise my backswing but it throws me off a bit. <y speed is only like 12 mph with a 15lb ball (according to the house camera's) but it hooks a lot and carries. I'l like a bit more mph. What mph are you throwing?