IW playing conditions were actually slower this year:
Please note this is a Court Pace Index and comes directly from Hawkeye data. So it's actually a true representation of the court speed for the speed of the court that year at each tournament. As it's an index it also factors in the climate / weather conditions not just the surface.
As for Miami, from what I can tell you the surface used -Laykold Cushion Plus- has a lower bounce than IW's Plexipave IW (it's still a medium-high bounce per se
), which means a lower COR, -coefficient of restitution-. This is a short explanation on how COR impacts on a court's pace:
Friction (COF) and vertical restitution (COR) are combined by ITF to give CPR -court pace rating-, using this equation:
We can infer that Laykold's CPR is higher than Plexipave IW's one as my observations are consistent with ITF's classification of boths surfaces:
- As a Cat. 1, slow-paced surface
, IW court's CPR is less than 29.
- As a Cat. 3, medium-paced surface
, Miami court's CPR is spread between 35 and 39.
But CPR is a limited index as it does not factor in the prevailing environmental conditions such as:
- Maximum and minimum temperature of the air, surface and test balls.
- Maximum and minimum relative humidity.
- Maximum and minimum atmospheric pressure.
- Condition of the surface, i.e. dry, damp, etc.
So I'm afraid we have to wait for Tennis tv next update of the CPI.