A penetrometer is an instrument that measures how firm a horse racing track is by driving a probe into the turf and recording how far it goes in. Racing Australia's track conditions pages print the reading in a Penetrometer column beside the track rating.
The reading is evidence for the rating, not the rating itself.
How a penetrometer works
The Brisbane Racing Club describes its own. A 1kg weight, released by a trigger, falls 1 metre down a shaft and drives a 1cm square rod into the soil, marked in 1cm steps to show how deep it went. The rod is driven three times at each of 60 positions around the track, and the reading is the total divided by the 180 drops. A higher number means softer ground and a lower one firmer.
In illustrative numbers, 180 drops that add up to 810 give a reading of 810 / 180 = 4.5.
How readings become a track rating
The club takes readings at least two days before a meeting, to plan the track work, and again on race morning, when the readings and a visual inspection decide the rating it posts. It also uses a Going Stick, and it says the rating is not assessed strictly to a scale of the penetrometer or Clegg hammer.
The rating lands on Racing Australia's 1 to 10 turf scale: Firm 1 to 2, Good 3 to 4, Soft 5 to 7 and Heavy 8 to 10. Track ratings explained covers each step of the scale and when ratings are updated.
Why readings vary around a track
One average covers the whole circuit, and the ground under it need not be even, which is why the drops are spread over 60 positions. Sections wear and drain differently: the strip by the rail takes the most traffic until the rail moves, and low ground holds water after rain. With illustrative averages for four sections of 45 drops each:
| Section | Average of its drops |
|---|---|
| Home straight | 5.4 |
| Home turn | 4.6 |
| Back straight | 3.8 |
| Far turn | 4.2 |
| Whole track | (5.4 + 4.6 + 3.8 + 4.2) / 4 = 4.5 |
The published 4.5 hides a home straight 0.9 softer than average, where races finish.
Between tracks the numbers need not line up: with illustrative figures, one track can be rated Soft 5 on a reading of 6.5 and another Soft 6 on 5.7, since inspections also shape a rating. Caulfield's entry on Racing Australia's Victorian page for its 10 October 2026 meeting (checked 8 October 2026) listed Going Stick, penetrate and shear figures instead of a penetrometer reading.
Using a reading when you price a race
Two mistakes turn a reading into the wrong price:
- Pricing on the reading instead of the rating. The official rating is what the race is run on.
- Treating a morning figure as the afternoon's ground. Racing Australia prints rainfall for the last 24 hours and 7 days, and irrigation, beside each rating, and rain after the inspection changes the ground.
A rating change moves every runner's chance at once, from the topweight down. Wet track form covers repricing runners when it comes, and how to read a form guide shows how to read each runner's record by rating.
Risk: Betting involves risk. Track readings are a snapshot taken hours before a race, and ground that changes after them can turn any form read on its head. See responsible gambling for help.
Where B337 fits
B337 does not rate tracks or runners. The Terminal's flucs show which runners firmed and which drifted after a rating change, beside prices from 40+ bookmakers across racing and sports, read on a repeating cycle. A free account opens a limited view of the Terminal with live odds.
Risk: Betting involves risk. A drift or firm after a rating change is other punters' read of the new ground, not your price. See responsible gambling.