Mick Kinane knows a bit about winning Melbourne Cups.

The Irish jockey made history when he guided Vintage Crop home in 1993 to become the first European to win the great race.

Kinane also rode So You Think's sire High Chaparral in all his six group one victories and believes So You Think will struggle with the 3200m of the Melbourne Cup.

"He's undoubtedly a horse with a lot of pace, he finds going quick very easy," Kinane told the Age at Tuesday's Breakfast With The Stars at Flemington.

Kinane is in Melbourne as a guest of the Victoria Racing Club, which has invited all living Melbourne Cup-winning jockeys to be at Flemington to celebrate the 150th running of the Melbourne Cup.

Kinane also doubted the chances of European runner Profound Beauty, trained by Dermot Weld for whom he won the Cup on Vintage Crop.

"He [So You Think] started his run very early [in the Cox Plate] and put the race to bed very quickly, which is always the hallmark of a good horse.

"But I doubt his ability to get the 3200m. He started to struggle the last 50m - he was at the top of his run.

"He'll have to change his style to last [the distance]."

Kinane is a great admirer of High Chaparral.

"He was a pretty strong staying horse. I'm not surprised he has been such a great success [at stud], because he was so tough."

Kinane said he doubted High Chaparral himself could have run 3200m. "But he was never asked to."

As Kinane was potting the chances of the A$6 million Melbourne Cup favourite, bookmakers were one by one also falling off the bandwagon.

So much so that the $3.20 price they rolled So You Think into after Saturday's Cox Plate victory, has disappeared and been replaced with quotes of $4.30 to $4.50.

Last year's Cup winner Shocking, who So You Think replaced at the top of the market, is back as favourite at around $4.20.

Shocking's supporters might have been studying the weather forecast, with the Victorian weather bureau tipping a wet Melbourne Cup.

Yesterday's AAP headlines in Melbourne screamed: "Heavy Rain Odds On For Derby Day."

The bureau is being specific, saying rain will set in at 10pm Friday and increase in intensity in the early daylight hours of Saturday and continue all day.

It said the bottom-end prediction is for 20mm and the top end 30mm to 50mm. Showers are expected to continue from Sunday through to Cup Day on Tuesday.

Given the forecast, a slow track for the Cup is being tipped, which will not harm Shocking's chances.

It will, however, probably mean a few entrants will drop out, possibly even So You Think.

It's difficult to imagine Bart Cummings will be prepared to risk sending So You Think around over 3200m in extremely testing conditions.

The forecast is good news for the connections of Cambridge stayer Harris Tweed.

He's not an absolute mudder, but can handle it and wet conditions would put a few out of business.