I have a old style Cervelo P3 carbon. I just bought a set of Hed 3 rims. The original narrow ones. I know this has been discussed endlessly but I have searched all the threads I could find but I have never heard a answer to this question.

I know that these rims are best used with a 20c tire. My question is does anyone have a good idea of what my time loss over 40k would be using GP 4000s tires opposed to Supersonics? I know the Supersonic is probably the best tire for this rim but just how much is lost with the 4000s?

Thanks in advance for any information.