Subtle gear changes can often turn a horse's form around but Bart Cummings has gone all out with Roman Emperor ahead of Saturday's BMW at Rosehill.The AJC Australian Derby winner of last year has been sluggish since his second to Viewed in the Caulfield Cup in the spring and measures have been taken to sharpen him up.Off come the blinkers, Norton bit and nose roll, on go winkers and a cross-over nose band for the first time with the return of a lugging bit and a tongue tie.He may need all the he

Subtle gear changes can often turn a horse's form around but Bart Cummings has gone all out with Roman Emperor ahead of Saturday's BMW at Rosehill.

The AJC Australian Derby winner of last year has been sluggish since his second to Viewed in the Caulfield Cup in the spring and measures have been taken to sharpen him up.

Off come the blinkers, Norton bit and nose roll, on go winkers and a cross-over nose band for the first time with the return of a lugging bit and a tongue tie.

He may need all the help he can get to beat Theseo who is the favourite to go one better than he did last year and break through at 2400 metres.

The distance is of no concern for Roman Emperor but he would prefer the track to be better than slow.

He will start from the outside barrier which part-owner Rosemary Mula believes is an omen.

"I drew the barrier for the Derby and he came up with 16 of 16," Mula said.

"I drew the barrier for the BMW and he got 12 of 12. I think it could be an omen."

Michael Rodd will be hoping it is with the jockey puzzled by his lacklustre finish in the Ranvet Stakes.

"He tracked up really nicely and I thought I was a chance of winning on straightening up he let down so well, but then he petered out," Rodd said.

"Maybe he is not quite genuine but he is a very big horse and might have needed the fitness run as well.

"But it wouldn't surprise me if he came out and won."

Theseo and noted wet tracker Speed Gifted dominate betting with Roman Emperor at $17 with TAB's fixed odds on Friday but around $11 on the tote.

His stablemate Moatize, who ran a cracking third in the Australian Cup, is at $13 on both.

Moatize was injured after his third to Theseo in last year's Ranvet and had almost a year off.

He finished in front of his stablemate in this year's Ranvet and his patient part-owner Veronica King is hopeful more than confident of an upset.

"His Australian Cup run showed he was back and the 2400 metres suits him, but the rain is no good for us," she said.

"But he did run third on a slow track in the Queensland Derby so there is some form there."

One horse who can handle a wet track and has no worries with the distance is New Zealander Harris Tweed.

He won the Tulloch Stakes at the corresponding meeting last year before running a close second to Roman Emperor in the Derby.

He tackled the best stayers in the spring with a solid fifth in the Melbourne Cup and comes to Sydney third-up from a spell and off a Group One second in the New Zealand Stakes.

"He goes on any type of track, if it's wet it just means it's going to knock out a couple of the others," co-trained Bjorn Baker said.

"His form coming over to Australia, for once, is Group One form and he's holding his condition well."

Ominously, so if Theseo with trainer Gai Waterhouse declaring him ready and able.

"He is like a pig in mud at the moment," she said.

"He's just a warhorse and he'll be extremely difficult to beat.

"People say, will he handle the wet, will he run the 2400 metres? I have a very happy horse and when you have a happy horse that's half the battle."