Here’s a follow up to this topic.

I went back and carried out the same test on my database for each of the other race classes, and here are the results. All of these are average races times for 1200 meters on a track Rated as good.

Maidens: 71.605
Class 1: 71.0216
Class 2: 70.861
Class 3: 70.481
Class 4: 70.405
Class 5: 70.1266
Class 6: 69.8976

Now if you draw a graph of these figures you’ll see an almost linear reduction in race times between classes. (About .28s between each class on average.) We could say that if a Class 2 race was run at the Class 3 times then the leading runners could be said to have performed at the higher class level.

In a typical race, the race times are split between the start to home turn section and the home turn to the finish sections of a race. The latter being run at a “flat out” pace and the earlier section is referred to the race pace, where jockeys attempt to get their mounts into the best position ready for the finish run.

My big question is how much weight will cause a runner to perform .28s worse?

I think it was Rem Plante or Don Scott that created an Acceleration-Deceleration graph that showed that adding weight slowed a horse down, but taking weight off didn’t normally increase its speed.

I know that weight is most effective in the last 400m home turn to the finish of a race and if you watch a runner that’s carrying 59kg or more, you will almost always see that’s it’s unable to sprint in the final stages of the race and usually gets beaten.

So, the question is, what weight increase represents 0.28 seconds of race time. A 1200 meter race is run in 71 seconds, so the speed is 16.9 meters per second. So 0.28s = 4.732 meters, a horse is 2.4384m so 0.28 seconds represents 1.94 lengths, say 2 lengths.

Now if the Rem Plante, Don Scott or Paul Sagar’s are correct 1.5 kg = 1 length at 1200 meters, so the answer is 3Kg between classes. But racing has changed a lot since the 1960-1970’s so is the 1.5kg = 1 length still valid?