For those interested in the upcoming Belmont Stakes draw on June 1, as well as the upcoming establishment of morning line odds, it may be interesting to know that being the favourite in the betting for the final leg of the Triple Crown isn't all it's cracked up to be.
Since the turn of the 21st century, only four favourites in the betting have gone on to win the mile-and-a-half race at Belmont Park.
Nothing illustrates the unpredictable nature of horse racing than this statistic since one could assume that high-profile stakes races would be more likely to have results that closely reflect the inherent talent of the horses. Ultimately, however, morning line odds are simply a recommendation for bettors, and the actual post-time odds are determined by betting patterns, not so-called expert picks.

Triple Crown frustration in Belmont Stakes

From 2000 to 2014, six horses entered the Belmont Stakes with a chance of winning the Triple Crown, having won both the Kentucky Derby and the Preakness Stakes. All six were big favourites to complete the three-race sweep, but none of them were able to become the 12th Triple Crown winner and the first since Affirmed in 1978.
This did change, however, as favourites American Pharoah in 2015 and Justify in 2018 were able to finish the job.
The best explanation for this incidence of unpredictability at horse racing's highest level is that the Belmont Stakes is the longest race in the Triple Crown Series. Since 1926 (except for 2020, when it was shortened due to COVID-19), the race has been run at a distance of a mile-and-a-half, which at 12 furlongs is two more than the mile-and-a-quarter Kentucky Derby and two-and-a-half farther than the mile-and-three-sixteenths Preakness Stakes.

Most horses prepare for the Kentucky Derby and the other Triple Crown races by running in contests that are a mile-and-a-sixteenth and a mile-and-an-eighth in distance, so while past performances are helpful, they aren't conclusive due to the increase in the length of the Belmont Stakes. If a horse exhibits late closing speed in a shorter race but finishes out of the money despite making a significant move down the stretch, it probably won't be among the favourites in a longer race but could still be one of the strongest entries.

Belmont Stakes longshot successes are not necessarily surprises

This same phenomenon may help explain why 11 Belmont Stakes winners have left the starting gate with double-digit odds, including 70/1 longshot Sarava in 2002 when War Emblem was attempting to win the Triple Crown but faded to an eighth-place finish. Two years later, with Smarty Jones ready to break the 26-year Triple Crown drought, 36/1 Birdstone crashed the party.

Again in 2008, winner Da'Tara went off at 38/1, the longest odds in the field, while Kentucky Derby and Preakness Stakes winner Big Brown was the overwhelming favourite at odds of 1/4 but ended up trotting across the finish line in last place in the eight-horse field.

So beware of the odds in the Belmont Stakes, particularly as Essential Quality will be the likely favourite as he was in the Kentucky Derby, where he came in fourth.